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Gibel carp (Carassius gibelio) possesses a special ability to integrate exogenous sperm genome or chromosome fragments into its eggs for co-development, but the spontaneous formation probability is very low in allogynogenetic offspring. In this study, white crucian carp (C. cuvieri) sperm were treated by 0.25%, 0.5%, 1%, 2% and 4% trypsin solution for 10 minutes, or by 1% trypsin solution for 5, 10, 15, 20 and 25 minutes respectively, and then fertilized with mature eggs of allogynogenetic gibel carp clone A+. By comparing the changes of sperm structure and motility between control group and different treatment groups, also considering reproductive indexes, such as fertilization rate, hatching rate and survival rate, as well as occurrence rate of allo-octoploids, an effective method was established to integrate exogenous sperm genome into allogynogenetic gibel carp eggs to create allo-octoploids. The average survival rate and octoploid rate were (2.4±0.7)% and (16.3±0.5)% respectively when the eggs of gibel carp clone A+ were fertilized with white crucian carp sperm treated by 1% trypsin solution for 15 minutes. The effective method developed in this study will be a valuable way for creating novel genetic resources with excellent economic traits in gibel carp genetic breeding. Subsequently, 57 allo-octoploid adults were obtained by batch processing and flow cytometry screening from 6-month-old offspring, which can be used as core population for breeding of novel gible carp varieties with faster growth and or higher disease-resistance.
Gibel carp (Carassius gibelio) possesses a special ability to integrate exogenous sperm genome or chromosome fragments into its eggs for co-development, but the spontaneous formation probability is very low in allogynogenetic offspring. In this study, white crucian carp (C. cuvieri) sperm were treated by 0.25%, 0.5%, 1%, 2% and 4% trypsin solution for 10 minutes, or by 1% trypsin solution for 5, 10, 15, 20 and 25 minutes respectively, and then fertilized with mature eggs of allogynogenetic gibel carp clone A+. By comparing the changes of sperm structure and motility between control group and different treatment groups, also considering reproductive indexes, such as fertilization rate, hatching rate and survival rate, as well as occurrence rate of allo-octoploids, an effective method was established to integrate exogenous sperm genome into allogynogenetic gibel carp eggs to create allo-octoploids. The average survival rate and octoploid rate were (2.4±0.7)% and (16.3±0.5)% respectively when the eggs of gibel carp clone A+ were fertilized with white crucian carp sperm treated by 1% trypsin solution for 15 minutes. The effective method developed in this study will be a valuable way for creating novel genetic resources with excellent economic traits in gibel carp genetic breeding. Subsequently, 57 allo-octoploid adults were obtained by batch processing and flow cytometry screening from 6-month-old offspring, which can be used as core population for breeding of novel gible carp varieties with faster growth and or higher disease-resistance.
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A 8-week growth experiment was conducted to investigate the effect of dietary replacement of fish meal protein with meat and bone meal (MBM) on growth performance, feed utilization, blood physiological and biochemical indices, muscle chemical composition and texture characteristics in juvenile Furong crucian carp (Furong carp♀× red crucian carp♂) [initial body weight of (17.47±2.56) g]. Three isonitrogenous (Crude protein: 38%) and isolipidic (Crude lipid: 6.5%) diets were formulated with 0, 50% and 100% dietary fish meal protein replaced by MBM (Named FM, T1 and T2). The results showed that, no significant differences were found in weight gain rate (WGR), specific growth rate (SGR) and feeding rate (FR) between the FM, T1 and T2 groups (P>0.05), while the feed conversion ratio (FCR) of FM group was significantly higher than that of the T2 group (P<0.05). There was no significant difference in blood physiological and serum biochemical indices, except for the hemoglobin (HGB) and aspartic amino transferase (AST). The content of HGB in T1 and T2 group were significantly higher than that of the FM group (P<0.05). On the other hand, AST showed a downward trend with the increasing proportion of dietary MBM, and AST of T2 group was significantly higher than that of FM group. The crude lipid content of the dorsal muscle in T1 group was significantly lower than that in FM group. Meanwhile, with dietary fish meal substituted by MBM, the Asp, Glu, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, ΣEAA, ΣDAA and ΣTAA contents of dorsal muscle were decreased, while the elasticity and adhesion of dorsal muscle were increased. In summary, MBM is an acceptable alternative animal protein source for Furong crucian carp, and 100% dietary fish meal could be replaced by MBM without significantly adverse on growth of Furong crucian carp.
A 8-week growth experiment was conducted to investigate the effect of dietary replacement of fish meal protein with meat and bone meal (MBM) on growth performance, feed utilization, blood physiological and biochemical indices, muscle chemical composition and texture characteristics in juvenile Furong crucian carp (Furong carp♀× red crucian carp♂) [initial body weight of (17.47±2.56) g]. Three isonitrogenous (Crude protein: 38%) and isolipidic (Crude lipid: 6.5%) diets were formulated with 0, 50% and 100% dietary fish meal protein replaced by MBM (Named FM, T1 and T2). The results showed that, no significant differences were found in weight gain rate (WGR), specific growth rate (SGR) and feeding rate (FR) between the FM, T1 and T2 groups (P>0.05), while the feed conversion ratio (FCR) of FM group was significantly higher than that of the T2 group (P<0.05). There was no significant difference in blood physiological and serum biochemical indices, except for the hemoglobin (HGB) and aspartic amino transferase (AST). The content of HGB in T1 and T2 group were significantly higher than that of the FM group (P<0.05). On the other hand, AST showed a downward trend with the increasing proportion of dietary MBM, and AST of T2 group was significantly higher than that of FM group. The crude lipid content of the dorsal muscle in T1 group was significantly lower than that in FM group. Meanwhile, with dietary fish meal substituted by MBM, the Asp, Glu, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, ΣEAA, ΣDAA and ΣTAA contents of dorsal muscle were decreased, while the elasticity and adhesion of dorsal muscle were increased. In summary, MBM is an acceptable alternative animal protein source for Furong crucian carp, and 100% dietary fish meal could be replaced by MBM without significantly adverse on growth of Furong crucian carp.
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To investigate the expression and function of Trachinotus ovatus cathepsin B (TroCatB) gene in response to bacterial stimulation, TroCatB cDNA was cloned by RT-PCR and RACE technology and it was 2181 bp in length with a 391 bp 5' UTR, a 797 bp 3'UTR and an 993 bp ORF encoding of 330 amino acid residues. The estimated molecular mass and theoretical isoelectric point were 36.37 kD and 5.73, respectively. The TroCatB protein has a signal peptide (1Met-18Ala), a precursor peptide (25Leu-64Gly) and a typical papain family cysteine domain, containing 107Cys, 277His, 297Asn catalytic activity sites. Homology analysis showed that the homology of the TroCatB protein with other vertebrates was 67.0—90.9%, and the homology of the mature peptide region with other vertebrates was 73.7—92.4%. The N-J phylogenetic tree revealed that the scorpionfish and other fish clustered together, closest to the corpus callosum. Real-time quantitative PCR indicated that TroCatB mRNA expressed in various tissues with the highest level in spleen. Vibrio alginolyticus infection significantly induced the expression of TroCatB gene in spleen with peak level at 6h and head kidney tissues (P<0.05) with peak level at 12h. These results indicated that the domain and catalytic active sites of TroCatB protein are conserved during genetic evolution. The TroCatB gene regulates the physiological activities of the organism against bacterial immunity, and plays an important role in the innate immune defense of ovate to elucidate the function of TroCatB in the immune process and the pathogenesis of pathogens.
To investigate the expression and function of Trachinotus ovatus cathepsin B (TroCatB) gene in response to bacterial stimulation, TroCatB cDNA was cloned by RT-PCR and RACE technology and it was 2181 bp in length with a 391 bp 5' UTR, a 797 bp 3'UTR and an 993 bp ORF encoding of 330 amino acid residues. The estimated molecular mass and theoretical isoelectric point were 36.37 kD and 5.73, respectively. The TroCatB protein has a signal peptide (1Met-18Ala), a precursor peptide (25Leu-64Gly) and a typical papain family cysteine domain, containing 107Cys, 277His, 297Asn catalytic activity sites. Homology analysis showed that the homology of the TroCatB protein with other vertebrates was 67.0—90.9%, and the homology of the mature peptide region with other vertebrates was 73.7—92.4%. The N-J phylogenetic tree revealed that the scorpionfish and other fish clustered together, closest to the corpus callosum. Real-time quantitative PCR indicated that TroCatB mRNA expressed in various tissues with the highest level in spleen. Vibrio alginolyticus infection significantly induced the expression of TroCatB gene in spleen with peak level at 6h and head kidney tissues (P<0.05) with peak level at 12h. These results indicated that the domain and catalytic active sites of TroCatB protein are conserved during genetic evolution. The TroCatB gene regulates the physiological activities of the organism against bacterial immunity, and plays an important role in the innate immune defense of ovate to elucidate the function of TroCatB in the immune process and the pathogenesis of pathogens.
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To investigate the epidemiology and etiology of eel viral diseases, and isolate, cultivate and identify the eel virus, a new cell line (EEK) was established by tissue explant method from european eel anguilla anguilla. EEK cells were fibroblast-like cells and were maintained and subcultured 38 generations over a 12-months period. The optimization of medium, serum concentration and temperature was conducted. EEK cells can grow and proliferate normally in DMEM/F12 and L15, but cannot proliferate in MEM. The growth rate enhanced with the increased Fetal Bovine Serum (FBS)in the range of 5%—15%, and it decreased with more than 20% FBS and less then 5% FBS. The cells grew well in a temperature range of 22—27℃, but the growth rate reduced at the temperature below 17℃ or above 32℃. The virus sensitivity test revealed that the cell line was susceptible to the infection of Anguillid herpesvirusv (AnHV) and has obvious cytopathic effect. The establishment of a kidney cell line from european eels has increased the variety of fish cell lines, providing important experimental material for the diagnosis of eel viral diseases, the study of viral etiology and the development of virus vaccine.
To investigate the epidemiology and etiology of eel viral diseases, and isolate, cultivate and identify the eel virus, a new cell line (EEK) was established by tissue explant method from european eel anguilla anguilla. EEK cells were fibroblast-like cells and were maintained and subcultured 38 generations over a 12-months period. The optimization of medium, serum concentration and temperature was conducted. EEK cells can grow and proliferate normally in DMEM/F12 and L15, but cannot proliferate in MEM. The growth rate enhanced with the increased Fetal Bovine Serum (FBS)in the range of 5%—15%, and it decreased with more than 20% FBS and less then 5% FBS. The cells grew well in a temperature range of 22—27℃, but the growth rate reduced at the temperature below 17℃ or above 32℃. The virus sensitivity test revealed that the cell line was susceptible to the infection of Anguillid herpesvirusv (AnHV) and has obvious cytopathic effect. The establishment of a kidney cell line from european eels has increased the variety of fish cell lines, providing important experimental material for the diagnosis of eel viral diseases, the study of viral etiology and the development of virus vaccine.
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The study was conducted to evaluate the effects of dietary protein on condition factors, body composition and serum biochemical indices of juvenile Sinilabeo decorus Tungting(Nichols).Five isolipidic and isoenergetic diets were formulated containing 32.57%, 37.58%, 42.76%, 47.83% and 52.22%, respectively. A total of 450 juvenile S. decorus Tungting with the average initial weight of (14.10 ± 1.08) g were randomly distributed into five groups with three replicates per group containing 30 juvenile S. decorus Tungting per replicate for 60 days. The results indicated that the survival ratio (SR) and the feed conversion ratio (FCR) had no significant differences among groups (P>0.05). Protein efficiency declined with increased dietary protein levels (P<0.05). The weight gain rate (WGR) and the specific growth rate (SGR) of 52.22% group were significantly lower than those of 32.57% and 42.76% groups (P<0.05). The condition factor (CF) and the intestine length ratio (ILR) decreased with increased dietary protein levels, in which 52.22% group were significantly lower than 32.57% group (P<0.05). There was no significant difference in body chemical composition, except muscle crude protein and ash. With the increase of dietary protein level, the muscle crude protein increased. Seventeen amino acids were found in fish muscle. The contents of Met, Ile,Leu,Asp, Ser,Glu, Ala, Arg, ƩEAA, ΣDAA and ΣTAA in dorsal muscle of 32.57% group were significantly lower than those in 52.22% group. With the increase of dietary protein level, the triglyceride (TG) and very low-density lipoprotein cholesterol(VLDL-c) in serum were increased, except the 37.58% group. The optimum level of dietary protein for juvenile S. decorus Tungting is estimated to 37.58%—42.76% under the current experimental condition. Broken-line of SGR estimated that protein requirements for the maximum growth was about 42.91% for juvenile S. decorus Tungting.
The study was conducted to evaluate the effects of dietary protein on condition factors, body composition and serum biochemical indices of juvenile Sinilabeo decorus Tungting(Nichols).Five isolipidic and isoenergetic diets were formulated containing 32.57%, 37.58%, 42.76%, 47.83% and 52.22%, respectively. A total of 450 juvenile S. decorus Tungting with the average initial weight of (14.10 ± 1.08) g were randomly distributed into five groups with three replicates per group containing 30 juvenile S. decorus Tungting per replicate for 60 days. The results indicated that the survival ratio (SR) and the feed conversion ratio (FCR) had no significant differences among groups (P>0.05). Protein efficiency declined with increased dietary protein levels (P<0.05). The weight gain rate (WGR) and the specific growth rate (SGR) of 52.22% group were significantly lower than those of 32.57% and 42.76% groups (P<0.05). The condition factor (CF) and the intestine length ratio (ILR) decreased with increased dietary protein levels, in which 52.22% group were significantly lower than 32.57% group (P<0.05). There was no significant difference in body chemical composition, except muscle crude protein and ash. With the increase of dietary protein level, the muscle crude protein increased. Seventeen amino acids were found in fish muscle. The contents of Met, Ile,Leu,Asp, Ser,Glu, Ala, Arg, ƩEAA, ΣDAA and ΣTAA in dorsal muscle of 32.57% group were significantly lower than those in 52.22% group. With the increase of dietary protein level, the triglyceride (TG) and very low-density lipoprotein cholesterol(VLDL-c) in serum were increased, except the 37.58% group. The optimum level of dietary protein for juvenile S. decorus Tungting is estimated to 37.58%—42.76% under the current experimental condition. Broken-line of SGR estimated that protein requirements for the maximum growth was about 42.91% for juvenile S. decorus Tungting.
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To assess the water quality of Pearl River, the second largest river in China, water samples were collected from 43 sites in Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River during wet season and dry season, respectively, to analyze the molecular diversity of planktonic microbial eukaryotes as well as relationships between their community structures and physicochemical factors based on the terminal restriction fragment length polymorphism (T-RFLP). The results revealed that water bodies of Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River were seriously polluted by nitrogen and phosphorus, and the water were in poor quality. The diversity indexes of planktonic microbial eukaryotes in Guangdong Reach of Xijiang River were higher than those in Guangzhou Reach of Pearl River. The Shannon - Wiener indexes of samples collected in wet season were lower than those in dry season. There were significant differences in community structures of microbial eukaryotes from different seasons and regions. The community structures of planktonic microbial eukaryotes in Pearl River were affected by chemical oxygen demand, permanganate index, ammonia nitrogen, total nitrogen and total phosphorus. However, correlation coefficients between community structures and physicochemical factors were different depending on seasons and regions. In addition, one T-RF and six T-RFs were selected as possible sensitive species (Cystobasidium sp. or Protostelium nocturnum) and pollution - tolerant species (Acanthamoeba hatchetti, Babesia bicornis, Blastocystis sp., Botryosphaerella sudetica, Candida caryicola, Coccomyxa simplex, Cryptomonas ovata, Filos agilis, Stenophora robusta, Sulfonecta uniserialis and Theileria sp. etc.), respectively.
To assess the water quality of Pearl River, the second largest river in China, water samples were collected from 43 sites in Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River during wet season and dry season, respectively, to analyze the molecular diversity of planktonic microbial eukaryotes as well as relationships between their community structures and physicochemical factors based on the terminal restriction fragment length polymorphism (T-RFLP). The results revealed that water bodies of Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River were seriously polluted by nitrogen and phosphorus, and the water were in poor quality. The diversity indexes of planktonic microbial eukaryotes in Guangdong Reach of Xijiang River were higher than those in Guangzhou Reach of Pearl River. The Shannon - Wiener indexes of samples collected in wet season were lower than those in dry season. There were significant differences in community structures of microbial eukaryotes from different seasons and regions. The community structures of planktonic microbial eukaryotes in Pearl River were affected by chemical oxygen demand, permanganate index, ammonia nitrogen, total nitrogen and total phosphorus. However, correlation coefficients between community structures and physicochemical factors were different depending on seasons and regions. In addition, one T-RF and six T-RFs were selected as possible sensitive species (Cystobasidium sp. or Protostelium nocturnum) and pollution - tolerant species (Acanthamoeba hatchetti, Babesia bicornis, Blastocystis sp., Botryosphaerella sudetica, Candida caryicola, Coccomyxa simplex, Cryptomonas ovata, Filos agilis, Stenophora robusta, Sulfonecta uniserialis and Theileria sp. etc.), respectively.
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The growth and propagation of aquatic plants will be greatly suppressed if the water level rises promptly. Some aquatic plants, especially for some emergent plants, can form floating mats to avoid the effects of deep flooding. We studied the species composition and distribution pattern of floating mat to find which species could form floating mats more easily and survive in the process of increasing water level in Lake Erhai in 2017. A total of twenty-six aquatic species (attached to fifteen families and nineteen genera) were recorded. The concentrations of total nitrogen (TN), total phosphorus (TP) and total dissolved phosphorus (TDP) in the water under the floating mat were greater than those in the open water, while the concentration of dissolved oxygen (DO) was vice versa. The results showed that both species richness and biomass of the floating mat were positively correlated with the area of floating mat (P<0.01), and that the mean biomass of the floating mat was not significantly correlated with the area of floating mat (P>0.05). The longest root of the floating mat was significantly correlated with the area of floating mat in summer (P<0.01) but not in winter (P>0.05). Most of the floating mats distributed in the region within an offshore distance of sixty meters and the water depth less than 2 meters. The area of the most floating mats was less than 600 m2 (87% for summer and 95% for winter), and the number of species in the floating mats is less than 10, the longest root in the floating mats ranged from 40 to 120 centimeters. The frequency and relative biomass of Zizania latifolia were the greatest among all recorded species on the floating mats in two seasons (frequency: 73.33% in summer and 66.67%in winter; relative biomass: 43.38% in summer and 41.91% in winter). These results indicated that Z. latifolia was easier to form floating mats in escape of the stress of deep water than the other emergent species to explain its sino-dominance in the emergent community. The mechanism that Z. latifolia is easier to form floating mats than the other emergent plants deserves further investigations.
The growth and propagation of aquatic plants will be greatly suppressed if the water level rises promptly. Some aquatic plants, especially for some emergent plants, can form floating mats to avoid the effects of deep flooding. We studied the species composition and distribution pattern of floating mat to find which species could form floating mats more easily and survive in the process of increasing water level in Lake Erhai in 2017. A total of twenty-six aquatic species (attached to fifteen families and nineteen genera) were recorded. The concentrations of total nitrogen (TN), total phosphorus (TP) and total dissolved phosphorus (TDP) in the water under the floating mat were greater than those in the open water, while the concentration of dissolved oxygen (DO) was vice versa. The results showed that both species richness and biomass of the floating mat were positively correlated with the area of floating mat (P<0.01), and that the mean biomass of the floating mat was not significantly correlated with the area of floating mat (P>0.05). The longest root of the floating mat was significantly correlated with the area of floating mat in summer (P<0.01) but not in winter (P>0.05). Most of the floating mats distributed in the region within an offshore distance of sixty meters and the water depth less than 2 meters. The area of the most floating mats was less than 600 m2 (87% for summer and 95% for winter), and the number of species in the floating mats is less than 10, the longest root in the floating mats ranged from 40 to 120 centimeters. The frequency and relative biomass of Zizania latifolia were the greatest among all recorded species on the floating mats in two seasons (frequency: 73.33% in summer and 66.67%in winter; relative biomass: 43.38% in summer and 41.91% in winter). These results indicated that Z. latifolia was easier to form floating mats in escape of the stress of deep water than the other emergent species to explain its sino-dominance in the emergent community. The mechanism that Z. latifolia is easier to form floating mats than the other emergent plants deserves further investigations.
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Ptychobarbus dipogon is endemic to China and has been threatened by overfishing and biological invasion. To examine 956 individuals collected from Lhaze to Nyemo of Yarlung Zangbo River, the population resources and fishery management policies of this species were studied by using per-recruit models from October 2008 to September 2009, April 2012 to July 2012 and in March 2013 respectively. The total instantaneous annual mortality (Z) of female and male P. dipogon were 0.52/ and 0.70/year, respectively. The range of natural mortality (M) of female and male P. dipogon were 0.10—0.17/year and 0.14—0.24/year, respectively. The range of current fishing mortality (Fcur) was 0.35—0.42/year for females and 0.46-0.56/year for males. The range of spawning potential ratio of P. dipogon was 3.1%—6.7% for females and 9.8%—18.2% for males, both of which were all significantly lower than the threshold reference point (25%). These results indicated that the stock of P. dipogon had been over-exploited under the current fishery management policy. To evaluate protective effect of capture age and seasonal closure, 14 different fishery management policies were simulated. The results show that raising the fishing age to not less than 15 years or setting the season closure time from February to June can effectively protect the population of the diagonal nematode.
Ptychobarbus dipogon is endemic to China and has been threatened by overfishing and biological invasion. To examine 956 individuals collected from Lhaze to Nyemo of Yarlung Zangbo River, the population resources and fishery management policies of this species were studied by using per-recruit models from October 2008 to September 2009, April 2012 to July 2012 and in March 2013 respectively. The total instantaneous annual mortality (Z) of female and male P. dipogon were 0.52/ and 0.70/year, respectively. The range of natural mortality (M) of female and male P. dipogon were 0.10—0.17/year and 0.14—0.24/year, respectively. The range of current fishing mortality (Fcur) was 0.35—0.42/year for females and 0.46-0.56/year for males. The range of spawning potential ratio of P. dipogon was 3.1%—6.7% for females and 9.8%—18.2% for males, both of which were all significantly lower than the threshold reference point (25%). These results indicated that the stock of P. dipogon had been over-exploited under the current fishery management policy. To evaluate protective effect of capture age and seasonal closure, 14 different fishery management policies were simulated. The results show that raising the fishing age to not less than 15 years or setting the season closure time from February to June can effectively protect the population of the diagonal nematode.
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To discover the causes of sick black seabass, bacterial strain ZS201807 was isolated from the cultured Centropristis striata with the symptoms of white spots in gill and visceral organs. The biochemical and physiological characteristics of the isolated strain were studied by using conventional method, such as API 20 and 16S rDNA gene sequence.The bacteria were identified as Edwardsiella tarda. The artificial infection experiment indicated that the strain was the causative agent of sick Centropristis striata. Histopathological analysis revealed that the spleen and kidney were the main target organs with serious infection, such as a large number of erythrocyte infiltration in the spleen tissue, serious blood stasis, gill filaments capillary dilation, renal tubular cavity stenosis, glomerular enlargement, epithelial cell swelling and cell cavitation. Ultrastructural pathology showed that there was a large accumulation of rod bacteria in the spleen and head kidney tissue of the sick fish. The drug susceptibility test showed that the bacterium was sensitive to 14 kinds of drugs such as ciprofloxacin (per 5 μg), tetracycline (per 30 μg) and enrofloxacin (per 5 μg), and resistant to 13 kinds of drugs such as penicillin (per 10U), azithromycin (per 15 μg) and amikacin (per 30 μg). It was confirmed that the pathogen of the disease and death of the black seabass was slow Edwardsiella tarda.
To discover the causes of sick black seabass, bacterial strain ZS201807 was isolated from the cultured Centropristis striata with the symptoms of white spots in gill and visceral organs. The biochemical and physiological characteristics of the isolated strain were studied by using conventional method, such as API 20 and 16S rDNA gene sequence.The bacteria were identified as Edwardsiella tarda. The artificial infection experiment indicated that the strain was the causative agent of sick Centropristis striata. Histopathological analysis revealed that the spleen and kidney were the main target organs with serious infection, such as a large number of erythrocyte infiltration in the spleen tissue, serious blood stasis, gill filaments capillary dilation, renal tubular cavity stenosis, glomerular enlargement, epithelial cell swelling and cell cavitation. Ultrastructural pathology showed that there was a large accumulation of rod bacteria in the spleen and head kidney tissue of the sick fish. The drug susceptibility test showed that the bacterium was sensitive to 14 kinds of drugs such as ciprofloxacin (per 5 μg), tetracycline (per 30 μg) and enrofloxacin (per 5 μg), and resistant to 13 kinds of drugs such as penicillin (per 10U), azithromycin (per 15 μg) and amikacin (per 30 μg). It was confirmed that the pathogen of the disease and death of the black seabass was slow Edwardsiella tarda.
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Licorice (Glycyrrhiza cyrrhiza uralensis Fiseh) is known as the " king of all herbs” because of its characteristics of harmonizing various medicines. It is a common cheap medicine in China and is therefore used in aquaculture. Its main active components are polysaccharides, glycosides, alkaloids, organic acids and volatile oil. In aquaculture, the common methods of licorice administration include feeding, perfusing, injecting, soaking and sprinkling, by which way are used for immune conditioning, disease control and other purposes for aquatic animals. However, there are also some problems in use of licorice, such as unstable quality of medicinal materials, extensive use methods, less standardized prescriptions, and inaccurate naming and description. In this paper, the fishery value of licorice was reviewed.
Licorice (Glycyrrhiza cyrrhiza uralensis Fiseh) is known as the " king of all herbs” because of its characteristics of harmonizing various medicines. It is a common cheap medicine in China and is therefore used in aquaculture. Its main active components are polysaccharides, glycosides, alkaloids, organic acids and volatile oil. In aquaculture, the common methods of licorice administration include feeding, perfusing, injecting, soaking and sprinkling, by which way are used for immune conditioning, disease control and other purposes for aquatic animals. However, there are also some problems in use of licorice, such as unstable quality of medicinal materials, extensive use methods, less standardized prescriptions, and inaccurate naming and description. In this paper, the fishery value of licorice was reviewed.
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To search suitable reference genes for normalization of quantitative Real-Time PCR (qRT-PCR) in Moina macrocopa, we tested three reference genes of β-actin, 16S rRNA and 12S rRNA by using four analysis methods: (1) expression level of the genes (cycle threshold value); (2) GeNorm; (3) NormFinder; and (4) BestKeeper. The results showed that the Ct values of the β-actin, 16S rRNA and 12S rRNA genes remained unchanged in M. macrocopa treated with different concentrations of phenol, and the order of the stability was 16S rRNA>12S rRNA>β-actin. GeNorm analysis revealed that the order of the stability was 16S rRNA=β-actin>12S rRNA. Both NormFinder and Bestkeeper software analysis demonstrated that the order of the stability was 16S rRNA>β-actin>12S rRNA. These results indicated that 16S rRNA was the best-fit reference gene for qRT-PCR in M. macrocopa, at least under phenol treatment, which provide useful information for future functional investigations of target gene expressions in M. macrocopa in response to environmental stress.
To search suitable reference genes for normalization of quantitative Real-Time PCR (qRT-PCR) in Moina macrocopa, we tested three reference genes of β-actin, 16S rRNA and 12S rRNA by using four analysis methods: (1) expression level of the genes (cycle threshold value); (2) GeNorm; (3) NormFinder; and (4) BestKeeper. The results showed that the Ct values of the β-actin, 16S rRNA and 12S rRNA genes remained unchanged in M. macrocopa treated with different concentrations of phenol, and the order of the stability was 16S rRNA>12S rRNA>β-actin. GeNorm analysis revealed that the order of the stability was 16S rRNA=β-actin>12S rRNA. Both NormFinder and Bestkeeper software analysis demonstrated that the order of the stability was 16S rRNA>β-actin>12S rRNA. These results indicated that 16S rRNA was the best-fit reference gene for qRT-PCR in M. macrocopa, at least under phenol treatment, which provide useful information for future functional investigations of target gene expressions in M. macrocopa in response to environmental stress.
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To study the individual biology of chum salmon, 447 samples were collected in Dongning section of the Suifen River from 2012 to 2017. The results showed that the age groups of samples were 1+—5+, of which 3+ and 2+ age are dominant for females and males respectively. The relationships between body weight and body length of male and female salmon were as follows: W=0.0082×L3.0604; W=0.0076×L3.0746, which were all belonged to the type of uniform growth. Von Bertalanffy growth function was used in simulating the fork length growth of chum salmon. The fork length growth equations of male and female chum salmon aged 3+ years were\begin{document}${L_{t,F}} = 141.64 \times {e^{ - 0.11 \cdot \left( {t + 1.55} \right)}}$\end{document} ![]()
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\begin{document}${L_{t,M}} = 119.51 \times {e^{ - 0.13 \cdot \left( {t + 1.45} \right)}}$\end{document} ![]()
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To study the individual biology of chum salmon, 447 samples were collected in Dongning section of the Suifen River from 2012 to 2017. The results showed that the age groups of samples were 1+—5+, of which 3+ and 2+ age are dominant for females and males respectively. The relationships between body weight and body length of male and female salmon were as follows: W=0.0082×L3.0604; W=0.0076×L3.0746, which were all belonged to the type of uniform growth. Von Bertalanffy growth function was used in simulating the fork length growth of chum salmon. The fork length growth equations of male and female chum salmon aged 3+ years were
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As a representative lake in Momoge Wetland Reserve, White Crane Lake is facing the risk of salinization and eutrophication.In order to slow down the salinization trend and provide research basis for the restoration of submerged vegetation and survival of species diversity of White Crane Lake, this study investigated physiological indexes of Ceratophyllum demersum in different alkalinity (0, 7, 10 and 17 mmol/L) and mixed saline-alkaline (salinity of 0.3, 0.6, 1, 2 and 4 g/L, corresponding alkalinity of 1.9, 3.8, 6.3, 12.6 and 25.2 mmol/L). The results showed that when the salinity was below 1.5 g/L, alkalinity had no effect on C. demersum. Within the range of the alkalinity gradient set in the experiment, C. demersum grown normally. Although C. demersum peroxidase (POD) and proline showed gradient change, C. demersum was still able to tolerate the alkalinity conditions below 17 mmol/L. With the increase of mixed saline-alkaline concentration, the growth of C. demersum showed a trend from flourish to decline. Under the condition of salinity of 0.6 g/L and alkalinity of 3.8 mmol/L, C. demersum had the best growth with the high-promoting and low-inhibiting ability. With the increase of salinity to 2 g/L and alkalinity to 12.6 mmol/L, C. demersum were under stress and survived partially, and the POD content increased sharply and the difference between plants was large. When salinity increased to 4 g/L and alkalinity reached 25.2 mmol/L, all C. demersum died after 21 days explained by the high concentration of mixed saline-alkaline and the low removal rate of nitrogen and phosphorus that are negatively correlated. This study provides reference for the restoration of submerged vegetation in salinized lakes.
As a representative lake in Momoge Wetland Reserve, White Crane Lake is facing the risk of salinization and eutrophication.In order to slow down the salinization trend and provide research basis for the restoration of submerged vegetation and survival of species diversity of White Crane Lake, this study investigated physiological indexes of Ceratophyllum demersum in different alkalinity (0, 7, 10 and 17 mmol/L) and mixed saline-alkaline (salinity of 0.3, 0.6, 1, 2 and 4 g/L, corresponding alkalinity of 1.9, 3.8, 6.3, 12.6 and 25.2 mmol/L). The results showed that when the salinity was below 1.5 g/L, alkalinity had no effect on C. demersum. Within the range of the alkalinity gradient set in the experiment, C. demersum grown normally. Although C. demersum peroxidase (POD) and proline showed gradient change, C. demersum was still able to tolerate the alkalinity conditions below 17 mmol/L. With the increase of mixed saline-alkaline concentration, the growth of C. demersum showed a trend from flourish to decline. Under the condition of salinity of 0.6 g/L and alkalinity of 3.8 mmol/L, C. demersum had the best growth with the high-promoting and low-inhibiting ability. With the increase of salinity to 2 g/L and alkalinity to 12.6 mmol/L, C. demersum were under stress and survived partially, and the POD content increased sharply and the difference between plants was large. When salinity increased to 4 g/L and alkalinity reached 25.2 mmol/L, all C. demersum died after 21 days explained by the high concentration of mixed saline-alkaline and the low removal rate of nitrogen and phosphorus that are negatively correlated. This study provides reference for the restoration of submerged vegetation in salinized lakes.
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Largemouth bronze gudgeon (Coreius guichenoti) is a potamodromous and endemic fish in the upper reaches of Yangtze River. An epidemic was found in largemouth bronze gudgeon at a farm in Luzhou, Sichuan province, southwest China, at the end of March 2012. In this study, we reported the first observation of furunculosis found in largemouth bronze gudgeon. One dominant bacteria strain, YTL1, was isolated from the liver of diseased largemouth bronze gudgeon, and a series of methods including morphological observation, biochemical tests, and phylogenetic analysis of 16S rRNA and six housekeeping genes were used to identify the pathogen. The strain was finally identified as A. salmonicida subsp. salmonicida based on the results. Antimicrobial susceptibility tests were carried out by the standard Kirby-Bauer disc diffusion method to screen effective drugs for the therapy of the disease, with results showing that YTL1 was sensitive to thirteen antibiotics such as florfenicol, norfloxacin, and ampicillin, resistant to 6 antibiotics such as bacitracin, streptomycin, and kanamycin, and mid-sensitive to erythromycin. Accordingly, florfenicol was added into diets to control furunculosis in largemouth bronze gudgeon with a good result. Artificial infection experiments in grass carp fingerlings and zebrafish resulted in the similar symptoms as diseased largemouth bronze gudgeon. In conclusion, our study demonstrated that multilocus sequence typing based on six housekeeping genes is an effective method to identify A. salmonicida strains to the subspecies level, confirmed that A. salmonicida infection is one of the greatest threats to artificial breeding and aquaculture of largemouth bronze gudgeon, and has expanded the susceptible hosts of A. salmonicida subsp. salmonicida to more cyprinid fishes.
Largemouth bronze gudgeon (Coreius guichenoti) is a potamodromous and endemic fish in the upper reaches of Yangtze River. An epidemic was found in largemouth bronze gudgeon at a farm in Luzhou, Sichuan province, southwest China, at the end of March 2012. In this study, we reported the first observation of furunculosis found in largemouth bronze gudgeon. One dominant bacteria strain, YTL1, was isolated from the liver of diseased largemouth bronze gudgeon, and a series of methods including morphological observation, biochemical tests, and phylogenetic analysis of 16S rRNA and six housekeeping genes were used to identify the pathogen. The strain was finally identified as A. salmonicida subsp. salmonicida based on the results. Antimicrobial susceptibility tests were carried out by the standard Kirby-Bauer disc diffusion method to screen effective drugs for the therapy of the disease, with results showing that YTL1 was sensitive to thirteen antibiotics such as florfenicol, norfloxacin, and ampicillin, resistant to 6 antibiotics such as bacitracin, streptomycin, and kanamycin, and mid-sensitive to erythromycin. Accordingly, florfenicol was added into diets to control furunculosis in largemouth bronze gudgeon with a good result. Artificial infection experiments in grass carp fingerlings and zebrafish resulted in the similar symptoms as diseased largemouth bronze gudgeon. In conclusion, our study demonstrated that multilocus sequence typing based on six housekeeping genes is an effective method to identify A. salmonicida strains to the subspecies level, confirmed that A. salmonicida infection is one of the greatest threats to artificial breeding and aquaculture of largemouth bronze gudgeon, and has expanded the susceptible hosts of A. salmonicida subsp. salmonicida to more cyprinid fishes.
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To understand the role of zebrafish finTRIM in antiviral innate immunity, the zebrafish ftr56 gene was cloned and analyzed for its effect on the proliferation of spring viremia of carp virus (SVCV). Primers were designed according to the zebrafish FTR56 sequence. The FTR56 CDS region was amplified by PCR and ligated into the eukaryotic expression vector pcDNA4.0-His to construct the eukaryotic expression plasmid pcDNA4.0-FTR56-His and conducted bioinformatics analysis. Real-time quantitative PCR (qRT-PCR) was used to detect the expression of FTR56 mRNA in SVCV-infected zebrafish embryo fibroblasts (ZF4). Phylogenetic tree analysis showed that the zebrafish FTR56 was individually clustered. The amino acid sequence alignment showed that the similarites with TRIM56 of chimpanzees, cattle and mice were 22%—23%. The FTR56 secondary structure has one RING finger domain, one B-box domain, one coiled-coil region and one B30.0 domain. The FTR56 mRNA level increased significantly at 24h after SVCV infection. After overexpression of FTR56, the mRNA and protein levels of G protein of SVCV reduced significantly at 12h and 24h compared with the control group associated with significantly decreased SVCV titers in the culture supernatant, indicating that FTR56 inhibited SVCV proliferation. This study provide a reference for further revealing the immunoregulatory mechanism of finTRIM in fish viral diseases.
To understand the role of zebrafish finTRIM in antiviral innate immunity, the zebrafish ftr56 gene was cloned and analyzed for its effect on the proliferation of spring viremia of carp virus (SVCV). Primers were designed according to the zebrafish FTR56 sequence. The FTR56 CDS region was amplified by PCR and ligated into the eukaryotic expression vector pcDNA4.0-His to construct the eukaryotic expression plasmid pcDNA4.0-FTR56-His and conducted bioinformatics analysis. Real-time quantitative PCR (qRT-PCR) was used to detect the expression of FTR56 mRNA in SVCV-infected zebrafish embryo fibroblasts (ZF4). Phylogenetic tree analysis showed that the zebrafish FTR56 was individually clustered. The amino acid sequence alignment showed that the similarites with TRIM56 of chimpanzees, cattle and mice were 22%—23%. The FTR56 secondary structure has one RING finger domain, one B-box domain, one coiled-coil region and one B30.0 domain. The FTR56 mRNA level increased significantly at 24h after SVCV infection. After overexpression of FTR56, the mRNA and protein levels of G protein of SVCV reduced significantly at 12h and 24h compared with the control group associated with significantly decreased SVCV titers in the culture supernatant, indicating that FTR56 inhibited SVCV proliferation. This study provide a reference for further revealing the immunoregulatory mechanism of finTRIM in fish viral diseases.
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We used living observation, protargol impregnation and silver staining methods to investigate the nuclei morphology and position, infraciliature, and oral apparatus of two oligohymenophorean ciliates: Paramecium primaurelia and Tetrahymena mimbres, which collected from hot springs of Tibet. SSU rDNA and COXⅠ genes of these two species were sequenced, and the phylogenetic analysis revealed that P. primaurelia is clustered in Paramecium aurelia complex, and T. mimbres is clustered in Tetrahymena borealis group. These two species are newly recorded in China from the hot springs of Tibet. The study of these two newly recorded species not only provides new methods and insights for the discovery of protozoa resources in the Tibetan hot springs, but also provides basic information for the study of protozoa environmental adaptation.
We used living observation, protargol impregnation and silver staining methods to investigate the nuclei morphology and position, infraciliature, and oral apparatus of two oligohymenophorean ciliates: Paramecium primaurelia and Tetrahymena mimbres, which collected from hot springs of Tibet. SSU rDNA and COXⅠ genes of these two species were sequenced, and the phylogenetic analysis revealed that P. primaurelia is clustered in Paramecium aurelia complex, and T. mimbres is clustered in Tetrahymena borealis group. These two species are newly recorded in China from the hot springs of Tibet. The study of these two newly recorded species not only provides new methods and insights for the discovery of protozoa resources in the Tibetan hot springs, but also provides basic information for the study of protozoa environmental adaptation.
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This study investigated annual variations of fish communities in different sections along the longitudinal gradient of the near-natural river based on the data collected from 2007 to 2016. A total of 134 fish species, belonged to 7 orders, 20 families and 84 genera, were collected. Among these species, Acipenser dabryanus and Myxocyprinus asiaticus have been enlisted as class Ⅰ and II protected species in China, while other 36 species endemic to the upper Yangtze River. The number of fish species increased along the longitudinal gradient, which increased from 47 in Chishui Town Section to 90 in the Chishui City Section and to 120 in the Hejiang County Section. Cluster analysis and non-metric multidimensional scaling (nMDS) ordination analysis revealed that the fish communities in all sections were varied significantly over time. The relative abundance of large and medium-sized economic fishes, such as S. sinensis and O. sima, declined continuously, while the small-sized fishes such as H. labeo, S. argentatus and R. giurinus showed the opposite trends. Additionally, the abundance of some endemic fish species, such as H. tchangi and C. guichenoti, declined markedly. The induced reasons included local overfishing, navigation, channel regulation and hydropower development, as well as changes of aquatic environment in the mainstream of the upper Yangtze River. In order to effectively protect fish stocks, it is recommended to strictly manage fisheries and water activities. Further strengthen long-term monitoring and timely detect changes in fish mix structure.
This study investigated annual variations of fish communities in different sections along the longitudinal gradient of the near-natural river based on the data collected from 2007 to 2016. A total of 134 fish species, belonged to 7 orders, 20 families and 84 genera, were collected. Among these species, Acipenser dabryanus and Myxocyprinus asiaticus have been enlisted as class Ⅰ and II protected species in China, while other 36 species endemic to the upper Yangtze River. The number of fish species increased along the longitudinal gradient, which increased from 47 in Chishui Town Section to 90 in the Chishui City Section and to 120 in the Hejiang County Section. Cluster analysis and non-metric multidimensional scaling (nMDS) ordination analysis revealed that the fish communities in all sections were varied significantly over time. The relative abundance of large and medium-sized economic fishes, such as S. sinensis and O. sima, declined continuously, while the small-sized fishes such as H. labeo, S. argentatus and R. giurinus showed the opposite trends. Additionally, the abundance of some endemic fish species, such as H. tchangi and C. guichenoti, declined markedly. The induced reasons included local overfishing, navigation, channel regulation and hydropower development, as well as changes of aquatic environment in the mainstream of the upper Yangtze River. In order to effectively protect fish stocks, it is recommended to strictly manage fisheries and water activities. Further strengthen long-term monitoring and timely detect changes in fish mix structure.
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Intermuscular bones (IBs) are common in the lower teleost and its morphology types and numbers are varied among different fish species. In this study, we documented the number, morphology, and distribution of IBs in Coilia nasus. The morphology of IBs in C. nasus was not different with Cyprinidae species; however, the distribution of IBs was quite different. Besides epineurals, epicentrals, and epipleurals, we found two others categories of IBs in C. nasus, which are located in the dorsal and ventral parts on both sides of the vertebrae. According to the reference, we called them dorsal and ventral myorhabdoi, respectively. These types of IBs were also identified in C. brachygnathus. The morphology of these IBs showed non-forked type (" 1” or " (”). The number of IBs in C. nasus ranged from 492 to 543, and the number of dorsal myorhabdoi, epineurals, epicentrals, epipleurals and ventral myorhabdoi ranged from 92 to 135 (\begin{document}$\bar x$\end{document} ![]()
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Intermuscular bones (IBs) are common in the lower teleost and its morphology types and numbers are varied among different fish species. In this study, we documented the number, morphology, and distribution of IBs in Coilia nasus. The morphology of IBs in C. nasus was not different with Cyprinidae species; however, the distribution of IBs was quite different. Besides epineurals, epicentrals, and epipleurals, we found two others categories of IBs in C. nasus, which are located in the dorsal and ventral parts on both sides of the vertebrae. According to the reference, we called them dorsal and ventral myorhabdoi, respectively. These types of IBs were also identified in C. brachygnathus. The morphology of these IBs showed non-forked type (" 1” or " (”). The number of IBs in C. nasus ranged from 492 to 543, and the number of dorsal myorhabdoi, epineurals, epicentrals, epipleurals and ventral myorhabdoi ranged from 92 to 135 (
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The genetic diversity of fish is seriously inferred from human disturbance factors such as water pollution and habitat destruction. Recent studies on the genetic diversity of fishes in small and medium-sized rivers in eastern China have focused on simple species, but there has been less comprehensive evaluation of fish genetic diversity and its causes. In this study, Cao’e River was selected as the representation of middle and small rivers in East China to evaluate the general genetic diversities of its fishes using mitochondrial cytochrome b gene. The results showed that the haplotype diversity indices (h) of Cyt b from the 21 species and 26 population were ranged from 0.074 to 0.987, and their nucleotide diversity indices (π) were ranged from 0.00019 to 0.00520. The genetic diversities among different species were large. Comparing the genetic diversities of fishes in different sections of Cao’s River, the haplotype diversity indices (h) of fishes decreased gradually from the estuary to upstream (P<0.05). The haplotype diversity indices (h) in species populations from Cao’e River were significantly lower than that of same species from large rivers such as the Yangtze River and Yellow River (P<0.05). The haplotype diversity indices (h) of sensitive fishes were significantly lower than those of middle tolerance fishes (P<0.05). Both the haplotype diversity indices (h) and nucleotide diversity indices (π) of three species, Pseudorasbora parva, Pelteobagrus nitidus and Mastacembelus aculeatus, in the populations from the upstream sampling site of Jinling were lower than those in the populations of same species from the sampling site of middle and lower reaches, Xianyan. This result implied that the overall genetic diversities of fishes from Cao’e River lied in middle or even low level, and that water pollution and overfishing might be the mainly reasons to reduce the genetic level of Cao’e River. In summary, our results provided an important theoretical basis for the management, protection, exploitation and utilization of fish resource of Cao’e River, and even of the middle and small rivers in East China.
The genetic diversity of fish is seriously inferred from human disturbance factors such as water pollution and habitat destruction. Recent studies on the genetic diversity of fishes in small and medium-sized rivers in eastern China have focused on simple species, but there has been less comprehensive evaluation of fish genetic diversity and its causes. In this study, Cao’e River was selected as the representation of middle and small rivers in East China to evaluate the general genetic diversities of its fishes using mitochondrial cytochrome b gene. The results showed that the haplotype diversity indices (h) of Cyt b from the 21 species and 26 population were ranged from 0.074 to 0.987, and their nucleotide diversity indices (π) were ranged from 0.00019 to 0.00520. The genetic diversities among different species were large. Comparing the genetic diversities of fishes in different sections of Cao’s River, the haplotype diversity indices (h) of fishes decreased gradually from the estuary to upstream (P<0.05). The haplotype diversity indices (h) in species populations from Cao’e River were significantly lower than that of same species from large rivers such as the Yangtze River and Yellow River (P<0.05). The haplotype diversity indices (h) of sensitive fishes were significantly lower than those of middle tolerance fishes (P<0.05). Both the haplotype diversity indices (h) and nucleotide diversity indices (π) of three species, Pseudorasbora parva, Pelteobagrus nitidus and Mastacembelus aculeatus, in the populations from the upstream sampling site of Jinling were lower than those in the populations of same species from the sampling site of middle and lower reaches, Xianyan. This result implied that the overall genetic diversities of fishes from Cao’e River lied in middle or even low level, and that water pollution and overfishing might be the mainly reasons to reduce the genetic level of Cao’e River. In summary, our results provided an important theoretical basis for the management, protection, exploitation and utilization of fish resource of Cao’e River, and even of the middle and small rivers in East China.
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Nitrite, a common pollutant in aquaculture, is an intermediate product of nitrogen cycle in ecosystem. To explore the mechanisms of sodium nitrite-induced cell apoptosis, grass carp liver cell (L8824) were exposed to four concentrations of sodium nitrite (0, 5 mg/L, 20 mg/L and 50 mg/L) with or without treatments of phosphoinositide receptor antagonist 2-APB and IRE1 inhibitors STF-083010. Cell apoptosis related gene expression of jnk, bcl-2, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and the cytoplasmic calcium ion concentration were assessed. The results showed that nitrite significantly increased the apoptosis rate, cytoplasm calcium ion concentration and mRNA levels of jnk, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and significantly decreased bcl-2 mRNA level, which were reversed by the STF-083010 treatment. Besides, both 2-APB and STF-083010 reduced the sodium nitrite-induced cytoplasmic calcium ion. These results indicate that endoplasmic reticulum stress-related IRE1 pathway plays pivotal role nitrite-mediated L8824 cell apoptosis and calcium dyshomeostasis.
Nitrite, a common pollutant in aquaculture, is an intermediate product of nitrogen cycle in ecosystem. To explore the mechanisms of sodium nitrite-induced cell apoptosis, grass carp liver cell (L8824) were exposed to four concentrations of sodium nitrite (0, 5 mg/L, 20 mg/L and 50 mg/L) with or without treatments of phosphoinositide receptor antagonist 2-APB and IRE1 inhibitors STF-083010. Cell apoptosis related gene expression of jnk, bcl-2, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and the cytoplasmic calcium ion concentration were assessed. The results showed that nitrite significantly increased the apoptosis rate, cytoplasm calcium ion concentration and mRNA levels of jnk, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and significantly decreased bcl-2 mRNA level, which were reversed by the STF-083010 treatment. Besides, both 2-APB and STF-083010 reduced the sodium nitrite-induced cytoplasmic calcium ion. These results indicate that endoplasmic reticulum stress-related IRE1 pathway plays pivotal role nitrite-mediated L8824 cell apoptosis and calcium dyshomeostasis.
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In order to explore the food composition of Procambarus clarkia and the food web structure in two different systems (crayfish-only system and integrated rice-crayfish symbiosis farming (IRCSF) system), we analyzed carbon and nitrogen stable isotope ratios (δ13C and δ15N) of sources and consumers, food web structure by SIBER and the food composition of P. clarkia by SIAR. The results showed that among the 19 collected species, the δ13C value of the consumer was between –34.22‰ to –25.34‰, the δ15N value was between2.33‰ to 8.05‰, and the trophic level was between1.46 to 3.64. The trophic level of P. clarkia in crayfish-only system was higher than that in IRCSF system. The metrics of food web reflected that the isotope niches in two systems using P. clarkia were similar. In IRCSF system, the trophic diversity in the food web was higher than that in crayfish-only system, and the niche overlap of each species and trophic redundancy in food web were lower than those in crayfish-only system. The significant positive correlation between the body length/weight and δ15N value of P. clarkia mean that P. clarkia prefer animal baits in two systems. The food contribution for P. clarkia was uniform and the proportion of plant baits was higher in IRCSF system compared with the crayfish-only system. The results indicated that the transfer loss of energy from sources to P. clarkia is higher in crayfish-only system, and the P. clarkia in IRCSF system was more herbivorous.
In order to explore the food composition of Procambarus clarkia and the food web structure in two different systems (crayfish-only system and integrated rice-crayfish symbiosis farming (IRCSF) system), we analyzed carbon and nitrogen stable isotope ratios (δ13C and δ15N) of sources and consumers, food web structure by SIBER and the food composition of P. clarkia by SIAR. The results showed that among the 19 collected species, the δ13C value of the consumer was between –34.22‰ to –25.34‰, the δ15N value was between2.33‰ to 8.05‰, and the trophic level was between1.46 to 3.64. The trophic level of P. clarkia in crayfish-only system was higher than that in IRCSF system. The metrics of food web reflected that the isotope niches in two systems using P. clarkia were similar. In IRCSF system, the trophic diversity in the food web was higher than that in crayfish-only system, and the niche overlap of each species and trophic redundancy in food web were lower than those in crayfish-only system. The significant positive correlation between the body length/weight and δ15N value of P. clarkia mean that P. clarkia prefer animal baits in two systems. The food contribution for P. clarkia was uniform and the proportion of plant baits was higher in IRCSF system compared with the crayfish-only system. The results indicated that the transfer loss of energy from sources to P. clarkia is higher in crayfish-only system, and the P. clarkia in IRCSF system was more herbivorous.
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Miniature inverted-repeat transposable elements (MITEs), a group of short and non-autonomous DNA transposons, are widely present in eukaryotic genomes. The location of the MITEs distribution would affect the host. In this study, MITEs in 33 fish genomes of the agnatha, chondrichthyes, sarcopterygii and actinopterygii were predicted and analyzed using bioinformatics approach. Ultimately, 2433 MITEs were identified in 33 fish genomes. MITEs content in 33 fish genomes varied from 0.11% to 21.18%, and MITEs content was positively correlated with fish genome size. MITEs were classified into 10 super families according to different terminal inverted repeats (TIRs) and target site duplications (TSDs) with the largest family of TC1-Mariner superfamily. The insertion of MITEs into the fish genome was mainly happened 4-0 million years ago, and most species had an explosive expansion between 2-0.5 million years ago. A number of fish MITEs were inserted into or near the genes, which may play an important role in the regulation of gene expression.
Miniature inverted-repeat transposable elements (MITEs), a group of short and non-autonomous DNA transposons, are widely present in eukaryotic genomes. The location of the MITEs distribution would affect the host. In this study, MITEs in 33 fish genomes of the agnatha, chondrichthyes, sarcopterygii and actinopterygii were predicted and analyzed using bioinformatics approach. Ultimately, 2433 MITEs were identified in 33 fish genomes. MITEs content in 33 fish genomes varied from 0.11% to 21.18%, and MITEs content was positively correlated with fish genome size. MITEs were classified into 10 super families according to different terminal inverted repeats (TIRs) and target site duplications (TSDs) with the largest family of TC1-Mariner superfamily. The insertion of MITEs into the fish genome was mainly happened 4-0 million years ago, and most species had an explosive expansion between 2-0.5 million years ago. A number of fish MITEs were inserted into or near the genes, which may play an important role in the regulation of gene expression.
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This study used Sepiella japonica as the research object to establish and optimize the acquisition method of high-turbidity water DNA (environmental DNA, eDNA) in Zhoushan offshore by absolute quantitative technique. The results indicated that the eDNA yield by ethanol precipitation method is 1.76-2.53 times higher than that of filtrating method, but the limitations of the collection volume, treatment requirement and supporting equipment make the ethanol precipitation method difficult to employ in practice. Filter screen with small aperture have no filtering effect on sediment. The size of filter aperture has a great effect on eDNA yield only when small volume water samples were collected. Precipitation treatment to water sample enhanced the yield of eDNA, but it also increased the variation of eDNA yield. Cationic surfactant significantly inhibited eDNA degradation. The effect of the membrane removal method is better than the membrane method, and it is recommended to increase the centrifugation time when the membrane removal method was used. Although the phenol extraction method can not improve the eDNA yield, it can significantly improve the purity of the product. This study is the first to establish an optimal method for obtaining eDNA of macro-organisms from Zhoushan offshore water, which provides reference for water sample collection and eDNA extraction in similar waters.
This study used Sepiella japonica as the research object to establish and optimize the acquisition method of high-turbidity water DNA (environmental DNA, eDNA) in Zhoushan offshore by absolute quantitative technique. The results indicated that the eDNA yield by ethanol precipitation method is 1.76-2.53 times higher than that of filtrating method, but the limitations of the collection volume, treatment requirement and supporting equipment make the ethanol precipitation method difficult to employ in practice. Filter screen with small aperture have no filtering effect on sediment. The size of filter aperture has a great effect on eDNA yield only when small volume water samples were collected. Precipitation treatment to water sample enhanced the yield of eDNA, but it also increased the variation of eDNA yield. Cationic surfactant significantly inhibited eDNA degradation. The effect of the membrane removal method is better than the membrane method, and it is recommended to increase the centrifugation time when the membrane removal method was used. Although the phenol extraction method can not improve the eDNA yield, it can significantly improve the purity of the product. This study is the first to establish an optimal method for obtaining eDNA of macro-organisms from Zhoushan offshore water, which provides reference for water sample collection and eDNA extraction in similar waters.
ISOLATION, IDENTIFICATION AND DETOXIFICATION OF A TRICHLORPHON- TOLERANT RHODOBACTERSPHAEROIDES XR12
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To explore the microbial resources to control trichlorphon pollution, a potential trichlorphon-tolerant bacterium XR12 was isolated and screened from the aquaculture sediment according to the physiological-biochemical characteristics and 16S rRNA gene sequence analysis, and its antibiotic resistance and its safety and detoxification effect were evaluated. The results indicated that strain XR12 exhibited the maximum tolerance concentration of 7680 mg/L trichlorphon. The strain XR12 was identified as Rhodobacter sphaeroides through phenotypic characterization and phylogenetic analysis based on 16S rRNA sequences. Its 16S rRNA sequence had homology of 98%－100% with strains of R. sphaeroides from GenBank, and showed the closest relation to R. sphaeroides strain RSF1 (GenBank accession number: KF606891). In addition, XR12 exhibited high sensitivity to kanamycin, roxithromycin, pipram, amoxicillin, florfenicol, polymyxin B, neomycin, gentamycin, ofloxacin, enrofloxacin, norfloxacin, streptomycin, tetracycline, netilmicin, intermediate sensitivity to doxycycline and resistance to bacitracin, nalidixic acid and sulfamethoxazole. XR12 had a LC50 of >109 cfu/mL for zebra fish, and could significantly enhance the LC50 of trichlorfon to zebrafish from 26.06 mg/L to 59.51 mg/L, indicating a good detoxification effect on trichlorfon. This study indicates that XR12 had the potential for trichlorfon detoxification in aquaculture water.
To explore the microbial resources to control trichlorphon pollution, a potential trichlorphon-tolerant bacterium XR12 was isolated and screened from the aquaculture sediment according to the physiological-biochemical characteristics and 16S rRNA gene sequence analysis, and its antibiotic resistance and its safety and detoxification effect were evaluated. The results indicated that strain XR12 exhibited the maximum tolerance concentration of 7680 mg/L trichlorphon. The strain XR12 was identified as Rhodobacter sphaeroides through phenotypic characterization and phylogenetic analysis based on 16S rRNA sequences. Its 16S rRNA sequence had homology of 98%－100% with strains of R. sphaeroides from GenBank, and showed the closest relation to R. sphaeroides strain RSF1 (GenBank accession number: KF606891). In addition, XR12 exhibited high sensitivity to kanamycin, roxithromycin, pipram, amoxicillin, florfenicol, polymyxin B, neomycin, gentamycin, ofloxacin, enrofloxacin, norfloxacin, streptomycin, tetracycline, netilmicin, intermediate sensitivity to doxycycline and resistance to bacitracin, nalidixic acid and sulfamethoxazole. XR12 had a LC50 of >109 cfu/mL for zebra fish, and could significantly enhance the LC50 of trichlorfon to zebrafish from 26.06 mg/L to 59.51 mg/L, indicating a good detoxification effect on trichlorfon. This study indicates that XR12 had the potential for trichlorfon detoxification in aquaculture water.
MACRO-PATTERNS OF SPECIES DIVERSITY AND STANDING CROPS OF MACROZOOBENTHOS IN THE YANGTZE RIVER BASIN
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We summarize macro-patterns of macrozoobenthos in the Yangtze River Basin in this paper. A total of 1033 taxa (species/genus) belonging to 3 phyla, 7 classes, 162 families and 513 genera have been recorded from the Yangtze River Basin, including 121 annelids, 318 molluscs and 594 arthropods. In terms of taxa distributions, the species/genus number of annelids and of molluscs in the middle reaches were highest, while that of arthropods in the upper reaches was highest; the species/genus number of annelids and of molluscs in the lakes were highest, while that of arthropods in the tributaries was highest; the species/genus number of macrozoobenthos in the middle mainstem sub-basin ranked first, and that of the upper mainstem sub-basin, of the Jinshajinag sub-basin, of the Lake Dongting sub-basin and of the Lake Poyang sub-basin second. The total density of macrozoobenthos in the Yangtze River Basin was 672 ind./m2, and insects were predominant; the total biomass was 34.22 g/m2, and molluscs were predominant. In terms of standing crops distribution, the total density of macrozoobenthos in the middle reaches was the highest, the total biomass in the lower reaches the highest, while the total standing crop in the upper reaches was the lowest; the total density and biomass of macrozoobenthos in the lakes ranked first, those in the tributaries second, and those in the mainstem last; the total density of macrozoobenthos in the Lake Taihu sub-basin was the highest, and the total biomass in the Lake Poyang sub-basin was the highest. Our study indicates that the upper and middle mainstem sub-basins, the Jinshajiang sub-basin, the Lake Dongting sub-basin and the Lake Poyang sub-basin are important distribution regions for macrozoobenthos. By integrating more information of aquatic organisms, we should make comprehensive and systematic conservation plans of the Yangtze River system and implement them as soon as possible.
We summarize macro-patterns of macrozoobenthos in the Yangtze River Basin in this paper. A total of 1033 taxa (species/genus) belonging to 3 phyla, 7 classes, 162 families and 513 genera have been recorded from the Yangtze River Basin, including 121 annelids, 318 molluscs and 594 arthropods. In terms of taxa distributions, the species/genus number of annelids and of molluscs in the middle reaches were highest, while that of arthropods in the upper reaches was highest; the species/genus number of annelids and of molluscs in the lakes were highest, while that of arthropods in the tributaries was highest; the species/genus number of macrozoobenthos in the middle mainstem sub-basin ranked first, and that of the upper mainstem sub-basin, of the Jinshajinag sub-basin, of the Lake Dongting sub-basin and of the Lake Poyang sub-basin second. The total density of macrozoobenthos in the Yangtze River Basin was 672 ind./m2, and insects were predominant; the total biomass was 34.22 g/m2, and molluscs were predominant. In terms of standing crops distribution, the total density of macrozoobenthos in the middle reaches was the highest, the total biomass in the lower reaches the highest, while the total standing crop in the upper reaches was the lowest; the total density and biomass of macrozoobenthos in the lakes ranked first, those in the tributaries second, and those in the mainstem last; the total density of macrozoobenthos in the Lake Taihu sub-basin was the highest, and the total biomass in the Lake Poyang sub-basin was the highest. Our study indicates that the upper and middle mainstem sub-basins, the Jinshajiang sub-basin, the Lake Dongting sub-basin and the Lake Poyang sub-basin are important distribution regions for macrozoobenthos. By integrating more information of aquatic organisms, we should make comprehensive and systematic conservation plans of the Yangtze River system and implement them as soon as possible.
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Myostatin propetide (MSTNpp) of Macrobrachium nipponenese was expressed in Bacillus subtilis and its effect on the growth and creatine kinase activity was investigated. The MSTNpp gene sequence was optimized to synthesize BsMSTNpp according to the B. subtilis preference codon, and the recombinant expression plasmid pGJ105-BsMSTNpp was obtained. After the transformation and fermentation of recombinant B. subtilis, the supernatant was collected and identified by Western blot. The results showed that the molecular weight of the recombinant protein was 36.0 kD. The level of recombinant BsMSTNpp increased over time, and the expression level at 100h was 10 times than that in 24h. To verify the biological activity of the recombinant BsMSTNpp, the healthy freshwater shrimp with an average body weight of 1.52 g and average body length of 4.55 cm were randomly divided into 4 groups with 3 replicates per group and 200 shrimps per replicate for a 30-days trial.The experimental group 1 and experimental group 2 were fed the basal diet supplemented with recombinant pGJ105-BsMSTNpp at the dose of 0.5×106 CFU/g and 1.0×106 CFU/g respectively. The control group 1 was fed the basal diet, and the control group 2 was fed the basal diet with pGJ105 at the dose of 1.0×106 CFU/g. The results showed that the growth ratios of the experimental groups were significantly higher than that of the control group 1 (P<0.05), and there was no significant difference between experimental groups and the control group 2. The creatine kinase activities of the experimental groups were higher than those of control groups (P<0.05). The results revealed that recombinant BsMSTNpp could enhance the activity of creatine kinase to improve the myocyte proliferation and differentiation to increase the muscle growth rate of Macrobrachium nipponenese. The results provide technical support to study the function of MSTNpp and its application in shrimp aquaculture.
Myostatin propetide (MSTNpp) of Macrobrachium nipponenese was expressed in Bacillus subtilis and its effect on the growth and creatine kinase activity was investigated. The MSTNpp gene sequence was optimized to synthesize BsMSTNpp according to the B. subtilis preference codon, and the recombinant expression plasmid pGJ105-BsMSTNpp was obtained. After the transformation and fermentation of recombinant B. subtilis, the supernatant was collected and identified by Western blot. The results showed that the molecular weight of the recombinant protein was 36.0 kD. The level of recombinant BsMSTNpp increased over time, and the expression level at 100h was 10 times than that in 24h. To verify the biological activity of the recombinant BsMSTNpp, the healthy freshwater shrimp with an average body weight of 1.52 g and average body length of 4.55 cm were randomly divided into 4 groups with 3 replicates per group and 200 shrimps per replicate for a 30-days trial.The experimental group 1 and experimental group 2 were fed the basal diet supplemented with recombinant pGJ105-BsMSTNpp at the dose of 0.5×106 CFU/g and 1.0×106 CFU/g respectively. The control group 1 was fed the basal diet, and the control group 2 was fed the basal diet with pGJ105 at the dose of 1.0×106 CFU/g. The results showed that the growth ratios of the experimental groups were significantly higher than that of the control group 1 (P<0.05), and there was no significant difference between experimental groups and the control group 2. The creatine kinase activities of the experimental groups were higher than those of control groups (P<0.05). The results revealed that recombinant BsMSTNpp could enhance the activity of creatine kinase to improve the myocyte proliferation and differentiation to increase the muscle growth rate of Macrobrachium nipponenese. The results provide technical support to study the function of MSTNpp and its application in shrimp aquaculture.
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To study the effects of fishmeal level and stocking density on the growth and immunity of juvenile black carp, a two-factor design of fishmeal level (10%, 20%) × culture density (50, 100, 200 tails / box) was applied. The young black carp (2.50 ± 0.02) g were divided into 6 groups of L50, L100, L200, H50, H100 and H200 with 3 replicates in each group using reservoir cages (1.5 m × 1.5 m × 1.5 m). In the early stage of experiment (week 8), the weight gain rate of black carp increased at first and then decreased with the increase of the stocking density, and the weight gain rate of the H200 group was higher than that of the L200 group (P>0.05), while it was significantly lower than that of the L200 group in the later stage (week 16) (P<0.05). The survival rate of the L200 group was lower than that of the L50 group (P>0.05). The stocking density and fishmeal levels showed an interactive effect on the survival rate and the weight gain rate (P<0.05). In the early stage, levels of lysozyme (LSZ) and serum glucose (GLU) of the low-fishmeal group decreased firstly and then increased with the increase of density, and intestinal secretory immunoglobulin A (S-IgA) increased. The levels of LSZ, complement C4, immunoglobulin M (IgM), S-IgA and cortisol of the H200 group were higher than those of the L200 group, while the GLU of the H200 group was lower than that of the L200 group (P>0.05). In the later stage, the level of C4 in the high and low fishmeal groups decreased at first and then increased with the increase of density (P>0.05). In the H200 group, the IgM and cortisol levels were higher than those of the L200 group, and the level of GLU was lower than that of the L200 group (P>0.05). In summary, high-density culture negatively regulate the growth performance, body’s immunity and anti-stress ability. The increased fishmeal level reversed the effects of high-density culture on growth performance, the immunity and anti-stress ability in the early stage. However, in the later stage, the increased fishmeal level only reduce high-density culture-mediated the survival rate without rescuing the growth performance and immune function.
To study the effects of fishmeal level and stocking density on the growth and immunity of juvenile black carp, a two-factor design of fishmeal level (10%, 20%) × culture density (50, 100, 200 tails / box) was applied. The young black carp (2.50 ± 0.02) g were divided into 6 groups of L50, L100, L200, H50, H100 and H200 with 3 replicates in each group using reservoir cages (1.5 m × 1.5 m × 1.5 m). In the early stage of experiment (week 8), the weight gain rate of black carp increased at first and then decreased with the increase of the stocking density, and the weight gain rate of the H200 group was higher than that of the L200 group (P>0.05), while it was significantly lower than that of the L200 group in the later stage (week 16) (P<0.05). The survival rate of the L200 group was lower than that of the L50 group (P>0.05). The stocking density and fishmeal levels showed an interactive effect on the survival rate and the weight gain rate (P<0.05). In the early stage, levels of lysozyme (LSZ) and serum glucose (GLU) of the low-fishmeal group decreased firstly and then increased with the increase of density, and intestinal secretory immunoglobulin A (S-IgA) increased. The levels of LSZ, complement C4, immunoglobulin M (IgM), S-IgA and cortisol of the H200 group were higher than those of the L200 group, while the GLU of the H200 group was lower than that of the L200 group (P>0.05). In the later stage, the level of C4 in the high and low fishmeal groups decreased at first and then increased with the increase of density (P>0.05). In the H200 group, the IgM and cortisol levels were higher than those of the L200 group, and the level of GLU was lower than that of the L200 group (P>0.05). In summary, high-density culture negatively regulate the growth performance, body’s immunity and anti-stress ability. The increased fishmeal level reversed the effects of high-density culture on growth performance, the immunity and anti-stress ability in the early stage. However, in the later stage, the increased fishmeal level only reduce high-density culture-mediated the survival rate without rescuing the growth performance and immune function.
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The Yangtze (Changjiang) river-floodplain is one of the most important ecosystems in China and the world, but is seriously threatened by multiple stresses. Thus, it is crucial and urgent to rehabilitate and conserve the river-floodplain. This paper reviews ecological studies conducted on the Yangtze river-floodplain, and presents suggestions for conservation and rehabilitation. First, basic concepts and research advances of riverscape and hydrological connectivity are introduced. Second, the history and current status of the Yangtze River system are summarized. Before 23 Ma, the Yangtze River cut through the Three Gorges, forming the river much like the modern one. Numerous rivers, streams, lakes (the total area 15,770 km2 at present) and wetlands are distributed in the mid-lower Yangtze river-floodplain. Such a river-lake complex ecosystem holds a unique and diverse biota, and is the most important fishery area of China. Third, main threats to the Yangtze river-floodplain ecosystem are identified, i.e., a) habitat loss, including river channelization, sharp shrinkage of lake area (ca. 10,000 km2 since the 1950s), degradation of lakeshore zones and sand over-mining; b) alternations of hydrological regimes, including construction of ca. 47,000 reservoirs and disconnection of most lakes from the mainstem; c) water pollution, including eutrophication, heavy metals, organic pollutants and microplastic; d) overexploitation of biological resources, including overfishing and intensive pen culture. Fourth, effects of river-lake disconnection on lake ecosystems are summarized. It was found that a) disconnection is one of the main causes of lake eutrophication; b) species diversity, biomass and production of macrophytes and macrobenthos reach maxima at some levels of intermediate river connectivity; c) disconnection greatly reduces fish species richness of each habitat guild, and natural fish larvae is severely depleted; d) disconnection simplifies macroinvertebrate food web structure, and trophic basis is more heavily relied on detritus in disconnected lakes. Last, conservation strategies are proposed. Since the Yangtze river-floodplain is a huge integrated system, the biodiversity conservation must be conducted on the whole basin scale. By establishing species-area models of fishes, the minimum protected area of Yangtze-connected lakes is estimated to be ca. 14,400 km2. It means that at least 8,900 km2 of disconnected lakes should be reconnected with the Yangtze mainstem, and ecohydrological operation of dams and sluices is the feasible approach. Based upon our studies on environmental flow requirements, the following measures are suggested: a) lower water levels during spring to improve germination of macrophytes, and control rising rates of water levels during spring-summer to ensure development of macrophytes; b) open sluice gates to restore migration routes for juveniles migrating into lakes during April-September, and for adults migrating back to the Yangtze mainstem during November-December.
The Yangtze (Changjiang) river-floodplain is one of the most important ecosystems in China and the world, but is seriously threatened by multiple stresses. Thus, it is crucial and urgent to rehabilitate and conserve the river-floodplain. This paper reviews ecological studies conducted on the Yangtze river-floodplain, and presents suggestions for conservation and rehabilitation. First, basic concepts and research advances of riverscape and hydrological connectivity are introduced. Second, the history and current status of the Yangtze River system are summarized. Before 23 Ma, the Yangtze River cut through the Three Gorges, forming the river much like the modern one. Numerous rivers, streams, lakes (the total area 15,770 km2 at present) and wetlands are distributed in the mid-lower Yangtze river-floodplain. Such a river-lake complex ecosystem holds a unique and diverse biota, and is the most important fishery area of China. Third, main threats to the Yangtze river-floodplain ecosystem are identified, i.e., a) habitat loss, including river channelization, sharp shrinkage of lake area (ca. 10,000 km2 since the 1950s), degradation of lakeshore zones and sand over-mining; b) alternations of hydrological regimes, including construction of ca. 47,000 reservoirs and disconnection of most lakes from the mainstem; c) water pollution, including eutrophication, heavy metals, organic pollutants and microplastic; d) overexploitation of biological resources, including overfishing and intensive pen culture. Fourth, effects of river-lake disconnection on lake ecosystems are summarized. It was found that a) disconnection is one of the main causes of lake eutrophication; b) species diversity, biomass and production of macrophytes and macrobenthos reach maxima at some levels of intermediate river connectivity; c) disconnection greatly reduces fish species richness of each habitat guild, and natural fish larvae is severely depleted; d) disconnection simplifies macroinvertebrate food web structure, and trophic basis is more heavily relied on detritus in disconnected lakes. Last, conservation strategies are proposed. Since the Yangtze river-floodplain is a huge integrated system, the biodiversity conservation must be conducted on the whole basin scale. By establishing species-area models of fishes, the minimum protected area of Yangtze-connected lakes is estimated to be ca. 14,400 km2. It means that at least 8,900 km2 of disconnected lakes should be reconnected with the Yangtze mainstem, and ecohydrological operation of dams and sluices is the feasible approach. Based upon our studies on environmental flow requirements, the following measures are suggested: a) lower water levels during spring to improve germination of macrophytes, and control rising rates of water levels during spring-summer to ensure development of macrophytes; b) open sluice gates to restore migration routes for juveniles migrating into lakes during April-September, and for adults migrating back to the Yangtze mainstem during November-December.
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Nearly 90% of the hydropower resources in the Yangtze River basin are concentrated in the upper reaches of the Yangtze River. The cascaded hydropower dams and river channelization have caused habitat fragmentation and loss of fish diversity, which has aggravated the contradictions between hydropower development and environmental protection. This paper collected data on aquatic reserves (i.e. natural reserves and aquatic germplasm resources conservation zones) and cascade dams in the upper reaches of the Yangtze River, and vectorized the data in ArcGIS. Taking into account the diversity, richness and distribution of fish, we analyzed the changes in fish resources and the problems in the construction and management of the upper reaches of the Yangtze River. Therefore, several strategies have been proposed to reduce the conflicts between hydropower development and aquatic ecosystem protection, including conducting reserve census, evaluating management effectiveness of the protected areas for spatial optimization of the reserve networks, implementing the ecological restoration of essential fish habitats, implementing the rescue action plan for the upper Yangtze endangered endemic fish, establishing an efficient ecological compensation mechanism, and strengthening scientific monitoring and related research. These recommendations will provide a scientific basis for the coordinated development of hydropower exploitation and river ecological protection in the upper Yangtze River.
Nearly 90% of the hydropower resources in the Yangtze River basin are concentrated in the upper reaches of the Yangtze River. The cascaded hydropower dams and river channelization have caused habitat fragmentation and loss of fish diversity, which has aggravated the contradictions between hydropower development and environmental protection. This paper collected data on aquatic reserves (i.e. natural reserves and aquatic germplasm resources conservation zones) and cascade dams in the upper reaches of the Yangtze River, and vectorized the data in ArcGIS. Taking into account the diversity, richness and distribution of fish, we analyzed the changes in fish resources and the problems in the construction and management of the upper reaches of the Yangtze River. Therefore, several strategies have been proposed to reduce the conflicts between hydropower development and aquatic ecosystem protection, including conducting reserve census, evaluating management effectiveness of the protected areas for spatial optimization of the reserve networks, implementing the ecological restoration of essential fish habitats, implementing the rescue action plan for the upper Yangtze endangered endemic fish, establishing an efficient ecological compensation mechanism, and strengthening scientific monitoring and related research. These recommendations will provide a scientific basis for the coordinated development of hydropower exploitation and river ecological protection in the upper Yangtze River.
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Sinibotia reevesae, an endemic fish, lives only in the upper reaches of the Yangtze River. This study explored the structure characteristics of Sinibotia reevesae brain and effects of the ecological habits on the central nervous system. The results showed that S. reevesae brain was composed of five parts of telencephalon, diencephalon, mesencephalon, cerebellum and myelecephalon. The olfactory lobe was a typical spindle shape and the preoptic nucleus of the brain was arranged in a cord-like manner without large preoptic nucleus and small cell group. The corpus mamillare and parasympathetic nucleus were visible in the diencephalon, meanwhile, saccus vasculosus and inferior lobeis were well developed. There were five layers in the tectum opticum of the mesencephalon and three layers in the cerebellum. The myelecephalon located in the end of the brain and differentiated into facial lobes and developed vagal lobes. Histological observations revealed that olfactory, auditory, tactile sensation, taste, motor centers and athletic ability of S. reevesae were well-developed. To sum up, the S. reevesae mainly depend on the sense of smell, hearing, touch, and taste to forage and to evade the natural enemies.
Sinibotia reevesae, an endemic fish, lives only in the upper reaches of the Yangtze River. This study explored the structure characteristics of Sinibotia reevesae brain and effects of the ecological habits on the central nervous system. The results showed that S. reevesae brain was composed of five parts of telencephalon, diencephalon, mesencephalon, cerebellum and myelecephalon. The olfactory lobe was a typical spindle shape and the preoptic nucleus of the brain was arranged in a cord-like manner without large preoptic nucleus and small cell group. The corpus mamillare and parasympathetic nucleus were visible in the diencephalon, meanwhile, saccus vasculosus and inferior lobeis were well developed. There were five layers in the tectum opticum of the mesencephalon and three layers in the cerebellum. The myelecephalon located in the end of the brain and differentiated into facial lobes and developed vagal lobes. Histological observations revealed that olfactory, auditory, tactile sensation, taste, motor centers and athletic ability of S. reevesae were well-developed. To sum up, the S. reevesae mainly depend on the sense of smell, hearing, touch, and taste to forage and to evade the natural enemies.
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To reveal the relationships between spawning activities of pelagophil fish and environmental factors in the Three Gorges Reservoir (TGR), fish eggs and larvae were sampled at Zhongxian section, from May to July in 2016 and 2017. 60 fish species including 30 pelagophil fishes were sampled. Hemiculter bleekeri and Squalidus argentatus were the dominant species in eggs, and Hemiculter and Pseudolaubuca were abundant in larvae. In 2016, 7.041 billion eggs and 103.763 billion larvae drifted through the sampling section, and in 2017, 3.454 billion eggs and 34.427 billion larvae drifted through the sampling section. The amount of eggs and larvae of the four major Chinese carps reached 2.909 billion in 2016 and 2.117 billionin in 2017. Spawning activities of pelagophils fish varies temporally in different river reaches, which mainly occurred after early-June in the river reach from Zhongxian to Fuling but begun in mid-May in the river reach upstream of Changshou. Fish eggs and larvae from the river reach upstream of Changshou provided a large resource for recruitment to the fishery in TGR. Classification and regression trees (CART) analysis explored that spawning activities of the four major Chinese carps were favord when water discharge was rasing. But, spawning activities of Hemiculter bleekeri and Squalidus argentatus had no relationship with water discharge. In order to protect the spawning grounds and meet environmental requirements for natural reproduction of pelagophils fish, we propose ecological regulation of the cascade hydro-power projects in the Jinsha River and maintenance of large free-flowing stretches upstream of TGR.
To reveal the relationships between spawning activities of pelagophil fish and environmental factors in the Three Gorges Reservoir (TGR), fish eggs and larvae were sampled at Zhongxian section, from May to July in 2016 and 2017. 60 fish species including 30 pelagophil fishes were sampled. Hemiculter bleekeri and Squalidus argentatus were the dominant species in eggs, and Hemiculter and Pseudolaubuca were abundant in larvae. In 2016, 7.041 billion eggs and 103.763 billion larvae drifted through the sampling section, and in 2017, 3.454 billion eggs and 34.427 billion larvae drifted through the sampling section. The amount of eggs and larvae of the four major Chinese carps reached 2.909 billion in 2016 and 2.117 billionin in 2017. Spawning activities of pelagophils fish varies temporally in different river reaches, which mainly occurred after early-June in the river reach from Zhongxian to Fuling but begun in mid-May in the river reach upstream of Changshou. Fish eggs and larvae from the river reach upstream of Changshou provided a large resource for recruitment to the fishery in TGR. Classification and regression trees (CART) analysis explored that spawning activities of the four major Chinese carps were favord when water discharge was rasing. But, spawning activities of Hemiculter bleekeri and Squalidus argentatus had no relationship with water discharge. In order to protect the spawning grounds and meet environmental requirements for natural reproduction of pelagophils fish, we propose ecological regulation of the cascade hydro-power projects in the Jinsha River and maintenance of large free-flowing stretches upstream of TGR.
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, doi: 10.7541/2019.128
Abstract:
This study re-described Myxobolus wulii (Wu & Li) Landsberg & Lom, 1991 and compared its strains in different sections of Yangtze River Basin (Chongqing strain, Hubei strain and Jiangsu strain) based on morphological and molecular (18S rDNA) data. The results showed that the spores and polar capsules of Chongqing strain were slightly smaller than those of Hubei strain, and that polar capsules and spores of Chongqing strain were equal in size while they were unequal for Hubei strain. The similarities and genetic distances among the three strains of M. wulii were 99.2%—99.9% and 0.002—0.007, respectively. Phylogenetic analysis showed that the sequences of M. wulii formed a poor geographical structure as well as poor host-original structure, but a strong parasitic site structure. The sequences of M. wulii clustered into two lineages: gill-parasites clade and hepatopancreas-parasites clade, indicating that the individuals of M. wulii have closer relationship with the same site of host. Moreover, the gill-parasites clade diverged earlier than hepatopancreas-parasites clade, which might be related to the evolution of external-parasites to internal-parasites. These data inferred that the gill-parasites population might be the earliest migrates of M. wulii.
This study re-described Myxobolus wulii (Wu & Li) Landsberg & Lom, 1991 and compared its strains in different sections of Yangtze River Basin (Chongqing strain, Hubei strain and Jiangsu strain) based on morphological and molecular (18S rDNA) data. The results showed that the spores and polar capsules of Chongqing strain were slightly smaller than those of Hubei strain, and that polar capsules and spores of Chongqing strain were equal in size while they were unequal for Hubei strain. The similarities and genetic distances among the three strains of M. wulii were 99.2%—99.9% and 0.002—0.007, respectively. Phylogenetic analysis showed that the sequences of M. wulii formed a poor geographical structure as well as poor host-original structure, but a strong parasitic site structure. The sequences of M. wulii clustered into two lineages: gill-parasites clade and hepatopancreas-parasites clade, indicating that the individuals of M. wulii have closer relationship with the same site of host. Moreover, the gill-parasites clade diverged earlier than hepatopancreas-parasites clade, which might be related to the evolution of external-parasites to internal-parasites. These data inferred that the gill-parasites population might be the earliest migrates of M. wulii.
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Habitat quality can directly affect population abundance and distribution of the Yangtze finless porpoise. This study investigated habitat status of both south and north banks of the main stem of the Yangtze River by taking high-resolution digital photos systematically during the 2017 Yangtze Freshwater Dolphin Expedition from November 10th to December 17th, 2017. The survey area covered the entire middle and lower reaches of the Yangtze River from Yichang to Shanghai (1669 km in length) and a total of 794 photo samples were collected. We recorded 318 sightings with 631 individuals of the Yangtze finless porpoise. The Chi-squared goodness of fit test revealed that proportions of observed frequency are significantly higher than the expected frequency in natural river banks (χ2=69.81, P<0.001). Whereas the result is opposite in the semi-natural and solidified river banks (χ2=39.26, P<0.001; χ2=12.15, P<0.001), indicating that the natural river banks were the preferred habitat of the Yangtze finless porpoise. The length of the semi-natural river and solidified banks accounted for 45.47% of the total length of the river bank, which intermingled with the patches of the natural river banks, demonstrating that the natural habitat was severely degraded and highly fragmented to impact the distribution of the Yangtze finless porpoise. Our study suggested that habitat degradation and fragmentation pose a significant threat to the survival of the Yangtze finless porpoise. Future conservation research and practice should focus on habitat restoration of the solidified river banks to reestablish and enhance habitat connectivity.
Habitat quality can directly affect population abundance and distribution of the Yangtze finless porpoise. This study investigated habitat status of both south and north banks of the main stem of the Yangtze River by taking high-resolution digital photos systematically during the 2017 Yangtze Freshwater Dolphin Expedition from November 10th to December 17th, 2017. The survey area covered the entire middle and lower reaches of the Yangtze River from Yichang to Shanghai (1669 km in length) and a total of 794 photo samples were collected. We recorded 318 sightings with 631 individuals of the Yangtze finless porpoise. The Chi-squared goodness of fit test revealed that proportions of observed frequency are significantly higher than the expected frequency in natural river banks (χ2=69.81, P<0.001). Whereas the result is opposite in the semi-natural and solidified river banks (χ2=39.26, P<0.001; χ2=12.15, P<0.001), indicating that the natural river banks were the preferred habitat of the Yangtze finless porpoise. The length of the semi-natural river and solidified banks accounted for 45.47% of the total length of the river bank, which intermingled with the patches of the natural river banks, demonstrating that the natural habitat was severely degraded and highly fragmented to impact the distribution of the Yangtze finless porpoise. Our study suggested that habitat degradation and fragmentation pose a significant threat to the survival of the Yangtze finless porpoise. Future conservation research and practice should focus on habitat restoration of the solidified river banks to reestablish and enhance habitat connectivity.
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Abstract:
In order to prove up the spatial distribution patterns of Sgassum vachellianum in Northern Zhejiang nearshore typical reefs, investigations were conducted on three reef belts with 12 reefs from the end of May to the beginning of June, 2016. Researchers carried out vessel-mounted observations and collected samples with SCUBA (Self-Contained Underwater Breathing Apparatus) to find out and compare the differentia of horizontal and vertical distribution features of S. vachellianum in adult stages. The results showed that (1) at the area scale, water environment with high turbidity and high wave energy inhibited the growth and spread of S. vachellianum which could merely be found on the second narrow reef belt. According to the growth characteristics of minimum appropriate water temperature with 10 ℃, it can be inferred that the northernmost island of Zhoushan Archipelago is the northernmost spread limit of endemic S. vachellianum to China. (2) At the site scale, the factor of wave exposure might explain the reason why S. vachellianum were sparse in southeast and were rich in northwest of reefs. The average height of S. vachellianum was only 26.3 cm on the four reefs of the second reef belt, which indicates high wave energy is not suitable for its growth. (3) Within the site scale, the North Yushan Island on the second reef belt was with lowest turbidity so that S. vachellianum were widespread, which could even be found in depth of 6.4 m. However, coastal waters with high turbidity withheld vertical distribution of S. vachellianum. As the result showed the average height of S. vachellianum decreases with depth, which can be inferred that S. vachellianum were intolerance of intense light, but light is a major factor for its distribution. Compared with the vertical distribution of Sargassum horneri in this region, S. vachellianum were adaptive to the environment with high turbidity and high sediment. Therefore, the change of inhibited water environment has driven S. vachellianum to the edge of extinction. By studying the causes of the spatial distribution of S. vachellianum, the decline of algae fields and the trend of variation, the conclusion can be drawn that S. vachellianum are suitable for artificial transplantation in Northern Zhejiang coastal area. The findings can provide meaningful references for the protection and restoration of algae fields.
In order to prove up the spatial distribution patterns of Sgassum vachellianum in Northern Zhejiang nearshore typical reefs, investigations were conducted on three reef belts with 12 reefs from the end of May to the beginning of June, 2016. Researchers carried out vessel-mounted observations and collected samples with SCUBA (Self-Contained Underwater Breathing Apparatus) to find out and compare the differentia of horizontal and vertical distribution features of S. vachellianum in adult stages. The results showed that (1) at the area scale, water environment with high turbidity and high wave energy inhibited the growth and spread of S. vachellianum which could merely be found on the second narrow reef belt. According to the growth characteristics of minimum appropriate water temperature with 10 ℃, it can be inferred that the northernmost island of Zhoushan Archipelago is the northernmost spread limit of endemic S. vachellianum to China. (2) At the site scale, the factor of wave exposure might explain the reason why S. vachellianum were sparse in southeast and were rich in northwest of reefs. The average height of S. vachellianum was only 26.3 cm on the four reefs of the second reef belt, which indicates high wave energy is not suitable for its growth. (3) Within the site scale, the North Yushan Island on the second reef belt was with lowest turbidity so that S. vachellianum were widespread, which could even be found in depth of 6.4 m. However, coastal waters with high turbidity withheld vertical distribution of S. vachellianum. As the result showed the average height of S. vachellianum decreases with depth, which can be inferred that S. vachellianum were intolerance of intense light, but light is a major factor for its distribution. Compared with the vertical distribution of Sargassum horneri in this region, S. vachellianum were adaptive to the environment with high turbidity and high sediment. Therefore, the change of inhibited water environment has driven S. vachellianum to the edge of extinction. By studying the causes of the spatial distribution of S. vachellianum, the decline of algae fields and the trend of variation, the conclusion can be drawn that S. vachellianum are suitable for artificial transplantation in Northern Zhejiang coastal area. The findings can provide meaningful references for the protection and restoration of algae fields.
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Abstract:
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
,
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Abstract:
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
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Abstract:
We generally reviewed the distributions and potential risks of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the upper reaches of the Yangtze River based on recent studies. The distribution of heavy metals varied significantly with locations and types of mediums, and contents of some metals exceeded the limits in food. The contents of PAHs in the upper reaches of the Yangtze River were in line with those in the lower reaches. Low molecular weight PAHs were predominant in surface water, while high molecular weight PAHs were predominant in sediments, indicating low molecular PAHs may pose greater risks to aquatic ecosystems. DEHP and DBP were the predominant monomers of PAEs in surface water and sediments, and BBP and DBP ranked first and second respectively in fish bodies. The results of risk assessment also indicated that monomers such as DBP and DnBP had greater risk than DEHP. Over all, heavy metals and organic pollutants were widely distributed in the aquatic environment in the upper reaches of the Yangtze River, which may pose potential risks to the ecosystem.
We generally reviewed the distributions and potential risks of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the upper reaches of the Yangtze River based on recent studies. The distribution of heavy metals varied significantly with locations and types of mediums, and contents of some metals exceeded the limits in food. The contents of PAHs in the upper reaches of the Yangtze River were in line with those in the lower reaches. Low molecular weight PAHs were predominant in surface water, while high molecular weight PAHs were predominant in sediments, indicating low molecular PAHs may pose greater risks to aquatic ecosystems. DEHP and DBP were the predominant monomers of PAEs in surface water and sediments, and BBP and DBP ranked first and second respectively in fish bodies. The results of risk assessment also indicated that monomers such as DBP and DnBP had greater risk than DEHP. Over all, heavy metals and organic pollutants were widely distributed in the aquatic environment in the upper reaches of the Yangtze River, which may pose potential risks to the ecosystem.
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The Chishui River, the only undammed first-order tributary of the upper Yangtze River Basin, is an important part of the " National Nature Reserve for Rare and Endemic Fishes of the Upper Yangtze River”, which plays important roles in fish conservation. To determine main environmental factors that affect the breeding activities of fishes with drifting eggs in this river, investigations on fish resources of early life stages were carried out in Chishui Reach from March to July in 2015 and April to August in 2016. A total of 27 species of fish early resources, belonging to 3 orders, 7 families and 22 genera, were collected during the investigation period. Nine of these species including Pseudolaubuca engraulis, Squalidus argentatus, Gobiobotia filifer, Botia superciliaris, Parabotia fasciata, Parabotia bimaculata, Leptobotia elongate, Leptobotia taeniops and Lepturichthys fimbriata laid drifting eggs in the running water. Canonical Correspondence Analysis (CCA) revealed various breeding environmental requirements for these species. Specially, B. superciliari, P. fasciata, P. bimaculata, L. elongate, L. taeniops and L. fimbriata tended to lay eggs when the water discharge was increasing, while P. engraulis and S. argentatus showed an opposite trend. Additionally, G. filifer preformed differently between 2015 and 2016. In the low flow year, their reproductive activities were positively associated with the water discharge. However, in the high flow year, no significant relation between the reproduction activities and water discharge was observed. These results strengthen our understanding of reproductive behavior of different fish species and provide valuable insights into fish conservation.
The Chishui River, the only undammed first-order tributary of the upper Yangtze River Basin, is an important part of the " National Nature Reserve for Rare and Endemic Fishes of the Upper Yangtze River”, which plays important roles in fish conservation. To determine main environmental factors that affect the breeding activities of fishes with drifting eggs in this river, investigations on fish resources of early life stages were carried out in Chishui Reach from March to July in 2015 and April to August in 2016. A total of 27 species of fish early resources, belonging to 3 orders, 7 families and 22 genera, were collected during the investigation period. Nine of these species including Pseudolaubuca engraulis, Squalidus argentatus, Gobiobotia filifer, Botia superciliaris, Parabotia fasciata, Parabotia bimaculata, Leptobotia elongate, Leptobotia taeniops and Lepturichthys fimbriata laid drifting eggs in the running water. Canonical Correspondence Analysis (CCA) revealed various breeding environmental requirements for these species. Specially, B. superciliari, P. fasciata, P. bimaculata, L. elongate, L. taeniops and L. fimbriata tended to lay eggs when the water discharge was increasing, while P. engraulis and S. argentatus showed an opposite trend. Additionally, G. filifer preformed differently between 2015 and 2016. In the low flow year, their reproductive activities were positively associated with the water discharge. However, in the high flow year, no significant relation between the reproduction activities and water discharge was observed. These results strengthen our understanding of reproductive behavior of different fish species and provide valuable insights into fish conservation.
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Eco-hydrological regulation of lakes have received more and more attentions in recent years, but systemic research on hydrological requirements of aquatic organisms still is limited. We systematically summarized the current status of aquatic plants and water level in the mid-lower Yangtze shallow lakes, influences of water level fluctuations on aquatic plants, and the requirement mode of water level fluctuation of aquatic plants. We also introduced a new method assessing ecological water level in shallow lakes based on aquatic plants, and provided corresponding strategies of water level regulations for lakes with different functions.
Eco-hydrological regulation of lakes have received more and more attentions in recent years, but systemic research on hydrological requirements of aquatic organisms still is limited. We systematically summarized the current status of aquatic plants and water level in the mid-lower Yangtze shallow lakes, influences of water level fluctuations on aquatic plants, and the requirement mode of water level fluctuation of aquatic plants. We also introduced a new method assessing ecological water level in shallow lakes based on aquatic plants, and provided corresponding strategies of water level regulations for lakes with different functions.
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We compiled the distribution and traits of 214 fish species and subspecies in the Jinsha River basin to investigate systematic and effective conservation planning in the basin. First, we modelled the distribution of widespread species throughout the basin with environmental factors such as climate, riverscape, land-use, and soil type; we used the occurrences as the distribution for other species. We planned the protected area (PA) network with the Marxan software to determine the species-specific conservation targets (grouped by mobility, distribution range, and conservation status) and evaluate the protection status of the current wetlands PAs. The best solution selected 486 planning units (47950 km2) that was 7.7% of the total planning units. The current wetlands PAs was not enough for fish conservation, which shelters 59.3% of all fishes (127 species) and 109 species require additional conservation area. The planning units’ area protected by the wetlands PA need to expand 55.9% to reach our conservation target.
We compiled the distribution and traits of 214 fish species and subspecies in the Jinsha River basin to investigate systematic and effective conservation planning in the basin. First, we modelled the distribution of widespread species throughout the basin with environmental factors such as climate, riverscape, land-use, and soil type; we used the occurrences as the distribution for other species. We planned the protected area (PA) network with the Marxan software to determine the species-specific conservation targets (grouped by mobility, distribution range, and conservation status) and evaluate the protection status of the current wetlands PAs. The best solution selected 486 planning units (47950 km2) that was 7.7% of the total planning units. The current wetlands PAs was not enough for fish conservation, which shelters 59.3% of all fishes (127 species) and 109 species require additional conservation area. The planning units’ area protected by the wetlands PA need to expand 55.9% to reach our conservation target.
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Abstract:
The Yangtze River basin harbors a high degree of fish diversity, with 378 fish species distributing in the mainstream and its attached waters, and 149 of these species are endemic to this river. Meanwhile, the Yangtze River is an important fishery ground in China, contributing more than 60% of the total catch of freshwater fishery. Therefore, the Yangtze River plays important roles in both biodiversity conservation and capture fisheries. However, due to the increasing human activities in the past decades, fish resources in the Yangtze River have declined sharply. Firstly, more and more species have been assessed as threatened and the endangerment categories of many species have been upgraded. Secondly, the population size of many iconic species, such as Acipenser sinensis, the four famous Chinese carps and Coreius guichenoti, have declined continuously. Thirdly, the miniaturization tendencies of major fishing targets have become more and more obvious. Last but not the least, the total fishery catch reduced significantly. Overfishing, water projects construction, enclosing-lake cultivation, water pollution and alien invasion were the main reasons contributing to these changes. In most situations, these factors interacted together, which imposed more damage to the fish resources and increased the difficulty of conservation. In order to protect the fish resources in the Yangtze River effectively, following conservation strategies are suggested: establishing specialized nature reserve, banning commercial fishing completely, implementing river ecological restoration, strengthening scientific research and establishing comprehensive regulation mechanism.
The Yangtze River basin harbors a high degree of fish diversity, with 378 fish species distributing in the mainstream and its attached waters, and 149 of these species are endemic to this river. Meanwhile, the Yangtze River is an important fishery ground in China, contributing more than 60% of the total catch of freshwater fishery. Therefore, the Yangtze River plays important roles in both biodiversity conservation and capture fisheries. However, due to the increasing human activities in the past decades, fish resources in the Yangtze River have declined sharply. Firstly, more and more species have been assessed as threatened and the endangerment categories of many species have been upgraded. Secondly, the population size of many iconic species, such as Acipenser sinensis, the four famous Chinese carps and Coreius guichenoti, have declined continuously. Thirdly, the miniaturization tendencies of major fishing targets have become more and more obvious. Last but not the least, the total fishery catch reduced significantly. Overfishing, water projects construction, enclosing-lake cultivation, water pollution and alien invasion were the main reasons contributing to these changes. In most situations, these factors interacted together, which imposed more damage to the fish resources and increased the difficulty of conservation. In order to protect the fish resources in the Yangtze River effectively, following conservation strategies are suggested: establishing specialized nature reserve, banning commercial fishing completely, implementing river ecological restoration, strengthening scientific research and establishing comprehensive regulation mechanism.
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Based on the Gini coefficient and Mann-Kendall test, the runoff variation in the Yichang reach of Yangtze River from 1982 to 2017 was evaluated, and its influence to the Chinese sturgeon spawning below the Gezhouba Dam was discussed under the cascaded hydropower operation. The results showed that the runoff and Gini coefficient decreased significantly after the construction of Gezhouba Dam, which synchronously decreased the flow and water levels in spawning days of the Chinese sturgeon. Water temperature had no significant change. The analysis of the abruption revealed great change of hydrological conditions in the spawning days and Gini coefficient in 2004 and 2009, which are coincided with time of the second and fourth phase impoundment of the Three Gorges Reservoir. The correlation analysis indicated that the higher runoff and Gini coefficient would induce Chinese sturgeon to spawn in days with high flow and water levels. These results suggest that the ecological operation of the Three Gorges-Gezhouba cascaded hydropower could enhance the runoff with large inequality and create long duration of high flow pulses during flood seasons.
Based on the Gini coefficient and Mann-Kendall test, the runoff variation in the Yichang reach of Yangtze River from 1982 to 2017 was evaluated, and its influence to the Chinese sturgeon spawning below the Gezhouba Dam was discussed under the cascaded hydropower operation. The results showed that the runoff and Gini coefficient decreased significantly after the construction of Gezhouba Dam, which synchronously decreased the flow and water levels in spawning days of the Chinese sturgeon. Water temperature had no significant change. The analysis of the abruption revealed great change of hydrological conditions in the spawning days and Gini coefficient in 2004 and 2009, which are coincided with time of the second and fourth phase impoundment of the Three Gorges Reservoir. The correlation analysis indicated that the higher runoff and Gini coefficient would induce Chinese sturgeon to spawn in days with high flow and water levels. These results suggest that the ecological operation of the Three Gorges-Gezhouba cascaded hydropower could enhance the runoff with large inequality and create long duration of high flow pulses during flood seasons.
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Lake Dongting is the second largest floodplain lake along the Yangtze River basin. However, the study on fish communities in the Dongting Lake is limited, lacking systematic research on the spatio-temporal variations of fish assemblages in this area. Fish were sampled seasonally from December 2012 to October 2014 in the Dongting Lake. 80 fish species belonging to54 genera, 17 families, and 7 orders with dominant Cyprinidae accounting for 58.8% of the total species were collected. The species richness reduced by 36 in contrast with the historic records. The number and percentage of riverine and river-sea migratory species decreased by 13 (2.2%) and 4 (3.0%) respectively in comparison with historic records. We detected significant seasonal and regional differences in species composition and biodiversity. The diversity and evenness of fishes were significantly higher in summer and autumn than those in other seasons. Meanwhile, significantly lower diversity was observed in the east Dongting Lake than other regions. Our results indicated that seasonal flood pulses and, assisting by river-lake connectivity may play a fundamental role for the fish resources supplement in floodplain lakes. This study demonstrated significant spatio-temporal variations of fish assemblages in the Dongting Lake, which provided scientific foundations for fish conservation in this area.
Lake Dongting is the second largest floodplain lake along the Yangtze River basin. However, the study on fish communities in the Dongting Lake is limited, lacking systematic research on the spatio-temporal variations of fish assemblages in this area. Fish were sampled seasonally from December 2012 to October 2014 in the Dongting Lake. 80 fish species belonging to54 genera, 17 families, and 7 orders with dominant Cyprinidae accounting for 58.8% of the total species were collected. The species richness reduced by 36 in contrast with the historic records. The number and percentage of riverine and river-sea migratory species decreased by 13 (2.2%) and 4 (3.0%) respectively in comparison with historic records. We detected significant seasonal and regional differences in species composition and biodiversity. The diversity and evenness of fishes were significantly higher in summer and autumn than those in other seasons. Meanwhile, significantly lower diversity was observed in the east Dongting Lake than other regions. Our results indicated that seasonal flood pulses and, assisting by river-lake connectivity may play a fundamental role for the fish resources supplement in floodplain lakes. This study demonstrated significant spatio-temporal variations of fish assemblages in the Dongting Lake, which provided scientific foundations for fish conservation in this area.
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Abstract:
Three Gorges Reservoir (TGR) is the key project for the governance and development of the Yangtze River. TGR is an important region for the ecological and environmental protection in the Yangtze River economic belt. The hydrology and water environment have taken fundamental changes since the impoundment of TGR with some negative ecological and environmental problems. To address whether the aquatic ecosystem of TGR is healthy or not, the phytoplankton community index (PhyCoI) was used to assess the ecosystem health of TGR. Field survey was carried out on April 2015 in the whole region of TGR, including 23 tributary bays and 18 sections in the main channel of TGR with 174 sampling sites. A total of 61 phytoplankton taxa were identified, belonging to Cyanophyta, Chlorophyta, Bacillariophyta, Cryptophyta, Pyrrophyta, Euglenophyta, and Chrysophyta. Based on the scores of PhyCoI, the overall health status of TGR is good, with 68% sites in the status of very healthy (4≤PhyCoI<5) or healthy (3≤PhyCoI<4), 26% sites in sub-healthy (2≤PhyCoI<3), and 6% sites in general sick condition (1≤PhyCoI<2). Specifically, 96% sites in the main channel of TGR are healthy, and other 4% sites are in the status of sub-healthy. In the tributary bays, the ratios for the status of very healthy, healthy, sub-healthy, and general sick are 2%, 53%, 35%, and 9%, respectively. From the view of spatial distribution, overall health status of the main channel of TGR is good, and the health status of the main channel in Hubei Province is better than that in the Chongqing Province. In addition, the health status of sites in the Xiangxi Bay, Meixi Bay, and Xiaojiang Bay were highly variable. And in general, the health status of the bays near the dam of TGR is better than the bays far away from the dam. These results provide science and technology support for ecological and environmental protection of TGR.
Three Gorges Reservoir (TGR) is the key project for the governance and development of the Yangtze River. TGR is an important region for the ecological and environmental protection in the Yangtze River economic belt. The hydrology and water environment have taken fundamental changes since the impoundment of TGR with some negative ecological and environmental problems. To address whether the aquatic ecosystem of TGR is healthy or not, the phytoplankton community index (PhyCoI) was used to assess the ecosystem health of TGR. Field survey was carried out on April 2015 in the whole region of TGR, including 23 tributary bays and 18 sections in the main channel of TGR with 174 sampling sites. A total of 61 phytoplankton taxa were identified, belonging to Cyanophyta, Chlorophyta, Bacillariophyta, Cryptophyta, Pyrrophyta, Euglenophyta, and Chrysophyta. Based on the scores of PhyCoI, the overall health status of TGR is good, with 68% sites in the status of very healthy (4≤PhyCoI<5) or healthy (3≤PhyCoI<4), 26% sites in sub-healthy (2≤PhyCoI<3), and 6% sites in general sick condition (1≤PhyCoI<2). Specifically, 96% sites in the main channel of TGR are healthy, and other 4% sites are in the status of sub-healthy. In the tributary bays, the ratios for the status of very healthy, healthy, sub-healthy, and general sick are 2%, 53%, 35%, and 9%, respectively. From the view of spatial distribution, overall health status of the main channel of TGR is good, and the health status of the main channel in Hubei Province is better than that in the Chongqing Province. In addition, the health status of sites in the Xiangxi Bay, Meixi Bay, and Xiaojiang Bay were highly variable. And in general, the health status of the bays near the dam of TGR is better than the bays far away from the dam. These results provide science and technology support for ecological and environmental protection of TGR.
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Abstract:
The Yangtze River is the largest river in China. It is a priority conservation area for biodiversity of the world, with its main river, branches and wetlands. As an essential part of freshwater ecosystem, aquatic vegetation has been well studied by Chinese researchers since 1950s, but large-scaled analysis on the biodiversity pattern is lacked. Based on published studies, we analyzed spatial and temporal pattern of aquatic plant diversity in the Yangtze River Basin, and calculated the suitable habitat area and underlying influence of environmental factors using MaxEnt software. A total of 298 species are recognized, belonging to 121 genera in 52 families, which is 57.6% of the total aquatic vascular plants in China. The Yangtze River Basin is the key area for aquatic plant diversity of China, especially the subregions of middle reaches. The elevation and land use are the key environmental variables to the spatial pattern of aquatic plants. The separation among water systems have weak influence on the spatial pattern of diversity in aquatic vascular plants, but potamo-lacustrine habitats facilitated the species homogenization of the flora in a sub-basin scale. The network consists of Poyang Lake, Dongting Lake, Tai Lake, and the middle and lower mainstream is the suitable area for the aquatic plants based on the MaxEnt model. In the past half century, the decline or loss of aquatic vegetation occurred in plenty of lakes in the Yangtze River Basin. We suggested that the protection of aquatic vegetation should be incorporated into the integrated conservation of the middle and lower Yangtze River.
The Yangtze River is the largest river in China. It is a priority conservation area for biodiversity of the world, with its main river, branches and wetlands. As an essential part of freshwater ecosystem, aquatic vegetation has been well studied by Chinese researchers since 1950s, but large-scaled analysis on the biodiversity pattern is lacked. Based on published studies, we analyzed spatial and temporal pattern of aquatic plant diversity in the Yangtze River Basin, and calculated the suitable habitat area and underlying influence of environmental factors using MaxEnt software. A total of 298 species are recognized, belonging to 121 genera in 52 families, which is 57.6% of the total aquatic vascular plants in China. The Yangtze River Basin is the key area for aquatic plant diversity of China, especially the subregions of middle reaches. The elevation and land use are the key environmental variables to the spatial pattern of aquatic plants. The separation among water systems have weak influence on the spatial pattern of diversity in aquatic vascular plants, but potamo-lacustrine habitats facilitated the species homogenization of the flora in a sub-basin scale. The network consists of Poyang Lake, Dongting Lake, Tai Lake, and the middle and lower mainstream is the suitable area for the aquatic plants based on the MaxEnt model. In the past half century, the decline or loss of aquatic vegetation occurred in plenty of lakes in the Yangtze River Basin. We suggested that the protection of aquatic vegetation should be incorporated into the integrated conservation of the middle and lower Yangtze River.
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PAEs have been proved to be one of the major organic pollutants. The present study determined the level of PAEs using surface water samples from the upper reaches of the Yangtze River. The results showed that DEHP contributed the most to PAEs pollution, followed by DBP. Risk Quotients of PAEs were used for preliminary screening, and DEHP and BBP were identified as potential risk factors with RQ of 310 and 70.7. The MOS10 of DEHP and BBP were 1.40 and 1.32×105, respectively, indicating that BBP may pose little risk to aquatic organisms. The potential risk of DEHP was further analyzed with joint probabilistic curves. Among different biological groups, fish and zoobenthos were two major groups sensitive to DEHP-induced damage under current concentrations with 99.4% and 98.3% for 5% species of each group. While among the toxicity endpoints, reproduction may be more sensitive than others. The 5% and 10% aquatic species were suffered from reproductive damages by 100% and 97.8%, respectively. Overall, our results indicated that DEHP in the surface water of the upper Yangtze River may pose potential risk to aquatic organisms, especially on their reproduction. Therefore, more concerns should be paid in species protection and environmental management.
PAEs have been proved to be one of the major organic pollutants. The present study determined the level of PAEs using surface water samples from the upper reaches of the Yangtze River. The results showed that DEHP contributed the most to PAEs pollution, followed by DBP. Risk Quotients of PAEs were used for preliminary screening, and DEHP and BBP were identified as potential risk factors with RQ of 310 and 70.7. The MOS10 of DEHP and BBP were 1.40 and 1.32×105, respectively, indicating that BBP may pose little risk to aquatic organisms. The potential risk of DEHP was further analyzed with joint probabilistic curves. Among different biological groups, fish and zoobenthos were two major groups sensitive to DEHP-induced damage under current concentrations with 99.4% and 98.3% for 5% species of each group. While among the toxicity endpoints, reproduction may be more sensitive than others. The 5% and 10% aquatic species were suffered from reproductive damages by 100% and 97.8%, respectively. Overall, our results indicated that DEHP in the surface water of the upper Yangtze River may pose potential risk to aquatic organisms, especially on their reproduction. Therefore, more concerns should be paid in species protection and environmental management.
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Abstract:
To better understand zooplankton distribution and its relationship with the physical-chemical factors in middle Yangtze River, we collected 20 zooplankton samples from segments at Yichang, Jingzhou, Yueyang, Wuhan and Hukou in October, 2016. A total of 23 species that belong to 13 families and 14 genera were identified, among which 16 species belong to Rotifera, 4 to Copepoda and 3 to Cladocera. Among the five segments, the highest number of zooplankton species was detected at Hukou (9 species), while the lowest was at Yueyang (5 species). The average density at Wuhan (10.94±5.81) ind./L was higher than that at Hukou and the other segments. Rotifers (3.41±0.21) ind./L were dominant in the zooplanktonic community, and Keratella valga, Synchacta atylata and Keratella cochlearis were the dominant species. The average density of copepods (mainly nauplius) was (0.75±0.07) ind./L. Cladocera had the lowest average density. Similarly, the zooplankton biomass at Wuhan was also higher than that at Hukou and the other three segments. Comparing with studies at other segments of Yangtze River, we detected lower zooplankton diversity in our investigation. Spearman correlations indicated that the biomass and diversity of zooplankton were significantly and positively correlated (P<0.05) to chlorophyll a.
To better understand zooplankton distribution and its relationship with the physical-chemical factors in middle Yangtze River, we collected 20 zooplankton samples from segments at Yichang, Jingzhou, Yueyang, Wuhan and Hukou in October, 2016. A total of 23 species that belong to 13 families and 14 genera were identified, among which 16 species belong to Rotifera, 4 to Copepoda and 3 to Cladocera. Among the five segments, the highest number of zooplankton species was detected at Hukou (9 species), while the lowest was at Yueyang (5 species). The average density at Wuhan (10.94±5.81) ind./L was higher than that at Hukou and the other segments. Rotifers (3.41±0.21) ind./L were dominant in the zooplanktonic community, and Keratella valga, Synchacta atylata and Keratella cochlearis were the dominant species. The average density of copepods (mainly nauplius) was (0.75±0.07) ind./L. Cladocera had the lowest average density. Similarly, the zooplankton biomass at Wuhan was also higher than that at Hukou and the other three segments. Comparing with studies at other segments of Yangtze River, we detected lower zooplankton diversity in our investigation. Spearman correlations indicated that the biomass and diversity of zooplankton were significantly and positively correlated (P<0.05) to chlorophyll a.
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Abstract:
The Yangtze floodplain is one of the most important wetlands in the world. For decades, many lakes in this region have suffered from multiple stressors, such as over-exploitation fishery resources and cultural eutrophication. To solve these problems, it is necessary to establish a quantitative lake ecosystem management platform at a regional scale. Recognizing the lack of regional scale zoobenthos models with high predictive power, we carried out 105 lake-time investigations on 46 small-to medium-sized lakes along the mid-lower Yangtze River in this study. The results showed that the density and biomass of zoobenthos of these lakes were (847±248) ind./m2 (mean±SE) and (29.41±3.97) g/m2, respectively. The density and biomass of oligochaetes, gastropods and chironomids were (403±225) ind./m2 and (1.12±0.39) g/m2, (82±20) ind./m2 and (26.38±3.99) g/m2, and (356±62) ind./m2 and (1.86±0.58) g/m2, respectively. Further analyses showed that water depth, Secchi depth, water temperature, total phosphorus, phytoplankton chlorophyll a, and submersed macrophyte biomass were the important factors affecting the standing crops of zoobenthos. A series of models were therefore established. The explanation of variations in zoobenthos density among lakes was generally better than that of biomass. The explantion percentage of simple regression models were between 18%—33% for density and 7%—18% for biomass. In the multiple regression models, the explanation percentage was 46%—49% for density and 16%—55% for biomass. Considering the large sampling size of this study, the explanation of these research models was significantly higher than that of previous studies. When comparing the percentage predictive errors (PPE), the simple models and multiple models showed similar results: PPE was 76%—171% for density and 115%—1034% for biomass in simple models, and 88%—114% for density and 141%—1015% for biomass in multiple models. Therefore, these simple regression model with relatively few variables and good predictive power are suggested in practical application.
The Yangtze floodplain is one of the most important wetlands in the world. For decades, many lakes in this region have suffered from multiple stressors, such as over-exploitation fishery resources and cultural eutrophication. To solve these problems, it is necessary to establish a quantitative lake ecosystem management platform at a regional scale. Recognizing the lack of regional scale zoobenthos models with high predictive power, we carried out 105 lake-time investigations on 46 small-to medium-sized lakes along the mid-lower Yangtze River in this study. The results showed that the density and biomass of zoobenthos of these lakes were (847±248) ind./m2 (mean±SE) and (29.41±3.97) g/m2, respectively. The density and biomass of oligochaetes, gastropods and chironomids were (403±225) ind./m2 and (1.12±0.39) g/m2, (82±20) ind./m2 and (26.38±3.99) g/m2, and (356±62) ind./m2 and (1.86±0.58) g/m2, respectively. Further analyses showed that water depth, Secchi depth, water temperature, total phosphorus, phytoplankton chlorophyll a, and submersed macrophyte biomass were the important factors affecting the standing crops of zoobenthos. A series of models were therefore established. The explanation of variations in zoobenthos density among lakes was generally better than that of biomass. The explantion percentage of simple regression models were between 18%—33% for density and 7%—18% for biomass. In the multiple regression models, the explanation percentage was 46%—49% for density and 16%—55% for biomass. Considering the large sampling size of this study, the explanation of these research models was significantly higher than that of previous studies. When comparing the percentage predictive errors (PPE), the simple models and multiple models showed similar results: PPE was 76%—171% for density and 115%—1034% for biomass in simple models, and 88%—114% for density and 141%—1015% for biomass in multiple models. Therefore, these simple regression model with relatively few variables and good predictive power are suggested in practical application.
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2019, 43(6): 1147 -1154
doi: 10.7541/2019.135
Abstract:
To investigate effects of dietary rapeseed meal on the growth performance, intestinal morphology, microflora, and the expression of small peptide transport related genes of grass carp (Ctenopharyngodon idellus), four isonitrogenous and isolipidic diets were formulated by adding 0, 5%, 10% and 15% fermented sesame meal to replace 0, 11.8%, 23.5% and 35.1% of rapeseed meal protein respectively, which were named as control group, trial group 1, trial group 2 and trial group 3. The experiment was carried out in an indoor recirculating system with three replicates in each group. Triplicates of 20 fish [initial body weight of (99.98±0.69) g] were fed to apparent satiation with four experiment diets twice a day for 45 days. The results showed no significant difference in weight gain rate (WGR), specific growth rate (SGR) and protein efficiency rate (PER) among all the groups, and WGR, SGR and PER of trial group 1 and 2 were slightly higher than those of the control group (P>0.05). Feed conversion ratio (FCR) of trial group 1 and 2 was slightly lower than that of the control group (P>0.05). The heights of intestinal villi in the trial groups were significantly higher than those of the control group (P<0.05), while the depth of crypt in the trial groups was significantly lower than that of the control group (P>0.05). The ratio of villi height to crypt depth (V/C) in the trial groups were significantly higher than that of the control group (P<0.05). Dietary fermented sesame meal significantly induced Lactobacillus and Bacillus (P<0.05) and significantly decreased Escherichia coli and Aeromonas (P<0.05). The expressions of CDX2, Sp1 and PepT1 genes increased significantly at first and then decreased with the increasing fermented sesame meal inclusion (P<0.05). These results suggest that the optimum proportion of fermented sesame meal replacement dietary rapeseed meal was 11.8%—23.5%.
To investigate effects of dietary rapeseed meal on the growth performance, intestinal morphology, microflora, and the expression of small peptide transport related genes of grass carp (Ctenopharyngodon idellus), four isonitrogenous and isolipidic diets were formulated by adding 0, 5%, 10% and 15% fermented sesame meal to replace 0, 11.8%, 23.5% and 35.1% of rapeseed meal protein respectively, which were named as control group, trial group 1, trial group 2 and trial group 3. The experiment was carried out in an indoor recirculating system with three replicates in each group. Triplicates of 20 fish [initial body weight of (99.98±0.69) g] were fed to apparent satiation with four experiment diets twice a day for 45 days. The results showed no significant difference in weight gain rate (WGR), specific growth rate (SGR) and protein efficiency rate (PER) among all the groups, and WGR, SGR and PER of trial group 1 and 2 were slightly higher than those of the control group (P>0.05). Feed conversion ratio (FCR) of trial group 1 and 2 was slightly lower than that of the control group (P>0.05). The heights of intestinal villi in the trial groups were significantly higher than those of the control group (P<0.05), while the depth of crypt in the trial groups was significantly lower than that of the control group (P>0.05). The ratio of villi height to crypt depth (V/C) in the trial groups were significantly higher than that of the control group (P<0.05). Dietary fermented sesame meal significantly induced Lactobacillus and Bacillus (P<0.05) and significantly decreased Escherichia coli and Aeromonas (P<0.05). The expressions of CDX2, Sp1 and PepT1 genes increased significantly at first and then decreased with the increasing fermented sesame meal inclusion (P<0.05). These results suggest that the optimum proportion of fermented sesame meal replacement dietary rapeseed meal was 11.8%—23.5%.
2019, 43(6): 1155 -1163
doi: 10.7541/2019.136
Abstract:
To investigate the effects of different forms of dietary methionine on rice field eel (Monopterus albus) [initial weight (30±0.45) g], Crystalline methionine (C-Met), encapsulated methionine (E-Met), methionine hydroxyl analog calcium salt (MHA-Ca) and methionine hydroxy analogue (MHA), whose effective Met content was 2 g/kg, were added in basal diet to form five experimental diets for a 10-week trial. Results showed that methionine in all forms improved weight gain rate and protein efficiency ratio and decreased feed conversion rate of rice field eels with significant change in groups of MHA-Ca and MHA compared with control group (P<0.05). Methionine addition significantly improved activity of trypsin, the contents of serum bile acid, total cholesterol, total protein, urea nitrogen and ammonia, muscle gumminess and adhesiveness (P<0.05). MHA-Ca and MHA addition improved the contents of serum glucose and HDL, activity of intestinal amylase, hepatosomatic GOT, crude protein of whole fish, muscle hardness, springiness and chewiness significantly (P<0.05), but reduced hepatosomatic index and serum glutamic oxalacetic transaminase activity significantly (P<0.05). The peak level of serum methionine appeared at 6h in control group after feeding, but at 9h in C-Met and MHA-Ca groups, at 12h in E-Met group, and at 3h and 9h in MHA group. These results revealed that methionine addition improved growth performance of rice field eels with better effects for MHA-Ca and MHA.
To investigate the effects of different forms of dietary methionine on rice field eel (Monopterus albus) [initial weight (30±0.45) g], Crystalline methionine (C-Met), encapsulated methionine (E-Met), methionine hydroxyl analog calcium salt (MHA-Ca) and methionine hydroxy analogue (MHA), whose effective Met content was 2 g/kg, were added in basal diet to form five experimental diets for a 10-week trial. Results showed that methionine in all forms improved weight gain rate and protein efficiency ratio and decreased feed conversion rate of rice field eels with significant change in groups of MHA-Ca and MHA compared with control group (P<0.05). Methionine addition significantly improved activity of trypsin, the contents of serum bile acid, total cholesterol, total protein, urea nitrogen and ammonia, muscle gumminess and adhesiveness (P<0.05). MHA-Ca and MHA addition improved the contents of serum glucose and HDL, activity of intestinal amylase, hepatosomatic GOT, crude protein of whole fish, muscle hardness, springiness and chewiness significantly (P<0.05), but reduced hepatosomatic index and serum glutamic oxalacetic transaminase activity significantly (P<0.05). The peak level of serum methionine appeared at 6h in control group after feeding, but at 9h in C-Met and MHA-Ca groups, at 12h in E-Met group, and at 3h and 9h in MHA group. These results revealed that methionine addition improved growth performance of rice field eels with better effects for MHA-Ca and MHA.
2019, 43(6): 1164 -1171
doi: 10.7541/2019.137
Abstract:
To investigate the effects of phytase on the growth, digestibility and nutrient utilization of juvenile Chinese mitten crab Eriocheir sinensis, six diets were designed that included the control group with no phytic acid (C) and phytase and five experimental groups with 10 g/kg of phytic acid and 0, 500, 1000, 1500 or 2000 U/kg phytase that were named as P0, P500, P1000, P1500 and P2000, respectively. Juvenile crabs with an initial body weight of (4.33±0.05) g were fed with these diets for 56 days. The results showed that the weight gain rate, specific growth rate and protein efficiency of the juvenile crabs in P0 group were lower than those of the C group, and the feed coefficient was higher than that of the C group (P<0.05). The weight gain rate, specific growth rate and protein efficiency of juvenile crab increased with the increased phytase with the highest one in P2000 that had the lowest feed coefficient (P<0.05). Phosphorus content of whole crabs of P1500 and P2000 was significantly higher than that of P0 (P<0.05). P2000 had the highest trypsin activity, amylase activity in the hepatopancreas and trypsin activity in the intestine of juvenile crabs (P<0.05). The protein digestibility and phosphorus dialysis rate of Eriocheir sinensis increased gradually with the increased phytase. P2000 had the highest nitrogen and phosphorus retention rates (P<0.05). These results indicated that 2000 U/kg phytase in the diet can significantly increase the growth, protein utilization rate and trypsin activity, and reduce the feed coefficient of juvenile crabs fed the diets containing phytic acid, and promote nitrogen/phosphorus deposition rate of juvenile crabs.
To investigate the effects of phytase on the growth, digestibility and nutrient utilization of juvenile Chinese mitten crab Eriocheir sinensis, six diets were designed that included the control group with no phytic acid (C) and phytase and five experimental groups with 10 g/kg of phytic acid and 0, 500, 1000, 1500 or 2000 U/kg phytase that were named as P0, P500, P1000, P1500 and P2000, respectively. Juvenile crabs with an initial body weight of (4.33±0.05) g were fed with these diets for 56 days. The results showed that the weight gain rate, specific growth rate and protein efficiency of the juvenile crabs in P0 group were lower than those of the C group, and the feed coefficient was higher than that of the C group (P<0.05). The weight gain rate, specific growth rate and protein efficiency of juvenile crab increased with the increased phytase with the highest one in P2000 that had the lowest feed coefficient (P<0.05). Phosphorus content of whole crabs of P1500 and P2000 was significantly higher than that of P0 (P<0.05). P2000 had the highest trypsin activity, amylase activity in the hepatopancreas and trypsin activity in the intestine of juvenile crabs (P<0.05). The protein digestibility and phosphorus dialysis rate of Eriocheir sinensis increased gradually with the increased phytase. P2000 had the highest nitrogen and phosphorus retention rates (P<0.05). These results indicated that 2000 U/kg phytase in the diet can significantly increase the growth, protein utilization rate and trypsin activity, and reduce the feed coefficient of juvenile crabs fed the diets containing phytic acid, and promote nitrogen/phosphorus deposition rate of juvenile crabs.
2019, 43(6): 1172 -1181
doi: 10.7541/2019.138
Abstract:
Phospholipase A2 plays a role in physiological and pathological processes such as phospholipid metabolism, inflammatory response, cell proliferation, and atherosclerosis. To investigate the biological function of sPLA2-III, five Ccpla2g3 paralogous genes located on different linkage groups were identified from the common carp (Cyprinus carpio) whole-genome using BLAST and synteny analysis performed by Genomicus, which named as Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3b, Ccpla2g3c1 and Ccpla2g3c2, respectively. Gene structure and sequence analysis showed that Ccpla2g3as contained 7 exons, whereas Ccpla2g3b and Ccspla2g3cs contained 4 exons. These five genes respectively encoded 530, 525, 461, 752 and 753 amino acids, and all contained the PLA2_bee_venom_like region and characteristic sequences of sPLA2-III. Synteny analysis indicated that Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3c1 and Ccpla2g3c2 were from the specific genome duplication of common carp. During evolution, the pla2g3a (b) in 2R (two rounds of genome duplication) fish, spotted gar (Lepisosteus oculatus) duplicated to pla2g3a and pla2g3b in 3R (fish-specific genome duplication, FSGD) fishes such as zebrafish (Danio rerio), but there was only one pla2g3c gene in 3R fishes because the other copy on the duplicated chromosome was lost. Homology analysis showed that the similarities of Pla2g3as, Pla2g3bs and Pla2g3cs of the analyzed fishes in orthologous proteins were 48.8%—93.2%, 37.6%—74.3% and 49.6%—97.6%, respectively, with the highest one between common carp and zebrafish. Phylogenetic analysis showed that Pla2g3cs of teleost’s and their ancestor, spotted gar, were grouped within the same branch with a bootstrap of 100; Pla2g3as and Pla2g3bs of spotted gar and teleost’s excluding common carp and zebrafish fell into one branch with a bootstrap of 96; Pla2g3bs of common carp and zebrafish formed a separate branch, demonstrating a larger variation of the gene during evolution. The expression of Ccpla2g3as was generally low during the whole early developmental stages of common carp, and it was higher in liver than other detected tissues (P<0.01) in adult fish; the expression level of Ccpla2g3b at 0.5h after fertilization was significantly higher than that of the later sampling points (P<0.05) with the highest level in ovary (P<0.01); the expression of Ccpla2g3cs reached the highest level at 120h, and it was higher in brain than in other parts. Generally, this study revealed the genetic structure, phylogeny and expression patterns of sPLA2-III in common carp.
Phospholipase A2 plays a role in physiological and pathological processes such as phospholipid metabolism, inflammatory response, cell proliferation, and atherosclerosis. To investigate the biological function of sPLA2-III, five Ccpla2g3 paralogous genes located on different linkage groups were identified from the common carp (Cyprinus carpio) whole-genome using BLAST and synteny analysis performed by Genomicus, which named as Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3b, Ccpla2g3c1 and Ccpla2g3c2, respectively. Gene structure and sequence analysis showed that Ccpla2g3as contained 7 exons, whereas Ccpla2g3b and Ccspla2g3cs contained 4 exons. These five genes respectively encoded 530, 525, 461, 752 and 753 amino acids, and all contained the PLA2_bee_venom_like region and characteristic sequences of sPLA2-III. Synteny analysis indicated that Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3c1 and Ccpla2g3c2 were from the specific genome duplication of common carp. During evolution, the pla2g3a (b) in 2R (two rounds of genome duplication) fish, spotted gar (Lepisosteus oculatus) duplicated to pla2g3a and pla2g3b in 3R (fish-specific genome duplication, FSGD) fishes such as zebrafish (Danio rerio), but there was only one pla2g3c gene in 3R fishes because the other copy on the duplicated chromosome was lost. Homology analysis showed that the similarities of Pla2g3as, Pla2g3bs and Pla2g3cs of the analyzed fishes in orthologous proteins were 48.8%—93.2%, 37.6%—74.3% and 49.6%—97.6%, respectively, with the highest one between common carp and zebrafish. Phylogenetic analysis showed that Pla2g3cs of teleost’s and their ancestor, spotted gar, were grouped within the same branch with a bootstrap of 100; Pla2g3as and Pla2g3bs of spotted gar and teleost’s excluding common carp and zebrafish fell into one branch with a bootstrap of 96; Pla2g3bs of common carp and zebrafish formed a separate branch, demonstrating a larger variation of the gene during evolution. The expression of Ccpla2g3as was generally low during the whole early developmental stages of common carp, and it was higher in liver than other detected tissues (P<0.01) in adult fish; the expression level of Ccpla2g3b at 0.5h after fertilization was significantly higher than that of the later sampling points (P<0.05) with the highest level in ovary (P<0.01); the expression of Ccpla2g3cs reached the highest level at 120h, and it was higher in brain than in other parts. Generally, this study revealed the genetic structure, phylogeny and expression patterns of sPLA2-III in common carp.
2019, 43(6): 1182 -1188
doi: 10.7541/2019.139
Abstract:
Fibroblast growth factor receptor homolog 1 (fgfrhl-1) gene is a member of the fgfr gene family currently detected only in the genomes of fish. The sequence of fgfrhl-1 is highly conserved during fish evolution, however, the distribution of fgfrhl-1 and its specific function remains unclear. In this study, we cloned the full-length cDNA of fgfrhl-1 from two distant fish species, the grass carp, Ctenopharyngodon idellus, and the Culter alburnus, and analyzed its expression in various adult tissues. The results showed that the full-length of fgfrhl-1 cDNA sequence of grass carp was 1472 bp, containing a 213 bp 5′-UTR, a 1203 bp open reading frame and a 56 bp 3′-UTR. The full-length fgfrhl-1 cDNA sequence of C. alburnus was 1886 bp, containing a 298 bp 5′-UTR, a 1203 bp open reading frame and a 385 bp 3′-UTR. The gene identified in both fish species encoded 400 amino acids, and the homology of the predicted amino acids sequences between them was 95.5%. The secondary structure prediction revealed that Fgfrhl-1 in both fish species has an intracellular tyrosine kinase domain, a transmembrane helix domain and an extracellular ligand recognizing and binding domain similar to those of FGFR, and that the extracellular domain of Fgfrhl-1 lacks three Ig-like domains that included in classical FGFRs. Semi-quantitative RT-PCR analysis explored that fgfrhl-1 was expressed in heart, gill, liver, spleen, caudal fin and intermuscular septum but not in muscle fibers in both fish species. In situ hybridization results revealed that fgfrhl-1 was expressed in connective tissues and vessels but not in the structure formed by mesenchymal cells. These results indicated the similar expression pattern of fgfrhl-1 of two different fish species mainly in the connective tissue and vessel cells of various tissues and organs, indicating that fish fgfrhl-1 may play a unique role in regulating differentiation or function maintenance of connective tissues and vessels.
Fibroblast growth factor receptor homolog 1 (fgfrhl-1) gene is a member of the fgfr gene family currently detected only in the genomes of fish. The sequence of fgfrhl-1 is highly conserved during fish evolution, however, the distribution of fgfrhl-1 and its specific function remains unclear. In this study, we cloned the full-length cDNA of fgfrhl-1 from two distant fish species, the grass carp, Ctenopharyngodon idellus, and the Culter alburnus, and analyzed its expression in various adult tissues. The results showed that the full-length of fgfrhl-1 cDNA sequence of grass carp was 1472 bp, containing a 213 bp 5′-UTR, a 1203 bp open reading frame and a 56 bp 3′-UTR. The full-length fgfrhl-1 cDNA sequence of C. alburnus was 1886 bp, containing a 298 bp 5′-UTR, a 1203 bp open reading frame and a 385 bp 3′-UTR. The gene identified in both fish species encoded 400 amino acids, and the homology of the predicted amino acids sequences between them was 95.5%. The secondary structure prediction revealed that Fgfrhl-1 in both fish species has an intracellular tyrosine kinase domain, a transmembrane helix domain and an extracellular ligand recognizing and binding domain similar to those of FGFR, and that the extracellular domain of Fgfrhl-1 lacks three Ig-like domains that included in classical FGFRs. Semi-quantitative RT-PCR analysis explored that fgfrhl-1 was expressed in heart, gill, liver, spleen, caudal fin and intermuscular septum but not in muscle fibers in both fish species. In situ hybridization results revealed that fgfrhl-1 was expressed in connective tissues and vessels but not in the structure formed by mesenchymal cells. These results indicated the similar expression pattern of fgfrhl-1 of two different fish species mainly in the connective tissue and vessel cells of various tissues and organs, indicating that fish fgfrhl-1 may play a unique role in regulating differentiation or function maintenance of connective tissues and vessels.
2019, 43(6): 1189 -1196
doi: 10.7541/2019.140
Abstract:
Tripartite motif-containing protein 25 (TRIM25) belongs to the E3 ubiquitin ligase family and plays an important role in innate immune response. To study the role of TRIM25 gene in innate antiviral immune response of large yellow croaker (Larimichthys crocea), the TRIM25 gene (named LcTRIM25) of large yellow croaker was cloned and identified. The coding sequence of LcTRIM25 gene is 2097 bp (GenBank accession numbers: MK327541), encoding 698 amino acid residues. Protein domain analysis found that LcTRIM25 contains a conserved Really Interesting New Gene (RING) domain, a B-box2 domain, a Coiled-coil domain and a variable C-terminal PRY/SPRY domain. Multiple sequence alignment and phylogenetic tree analysis showed that the LcTRIM25 gene had high homology with the Epinephelus coioides, but low homology with mammals, reptiles, amphibians and birds, indicating that the different species were under different selection pressure from environments to reach different evolutionary degrees. The results of real-time fluorescence quantitative PCR revealed that the LcTRIM25 gene was ubiquitously expressed in 9 tested issues of healthy large yellow croaker, with the highest expressions in liver and the lowest expression in heart. The expression of LcTRIM25 gene in peripheral blood, head kidney, spleen and liver were rapidly and significantly upregulated after poly (I:C) stimulation, and then decreased in all tissues. The highest expression level of LcTRIM25 gene was found at 6h in head kidney and spleen, at 12h in liver, and at 24h in peripheral blood, demonstrating that the TRIM25 gene might play a key role in the antiviral immune response of large yellow croaker. This study provides a theoretical basis for further understanding the antiviral immune mechanism of large yellow croaker.
Tripartite motif-containing protein 25 (TRIM25) belongs to the E3 ubiquitin ligase family and plays an important role in innate immune response. To study the role of TRIM25 gene in innate antiviral immune response of large yellow croaker (Larimichthys crocea), the TRIM25 gene (named LcTRIM25) of large yellow croaker was cloned and identified. The coding sequence of LcTRIM25 gene is 2097 bp (GenBank accession numbers: MK327541), encoding 698 amino acid residues. Protein domain analysis found that LcTRIM25 contains a conserved Really Interesting New Gene (RING) domain, a B-box2 domain, a Coiled-coil domain and a variable C-terminal PRY/SPRY domain. Multiple sequence alignment and phylogenetic tree analysis showed that the LcTRIM25 gene had high homology with the Epinephelus coioides, but low homology with mammals, reptiles, amphibians and birds, indicating that the different species were under different selection pressure from environments to reach different evolutionary degrees. The results of real-time fluorescence quantitative PCR revealed that the LcTRIM25 gene was ubiquitously expressed in 9 tested issues of healthy large yellow croaker, with the highest expressions in liver and the lowest expression in heart. The expression of LcTRIM25 gene in peripheral blood, head kidney, spleen and liver were rapidly and significantly upregulated after poly (I:C) stimulation, and then decreased in all tissues. The highest expression level of LcTRIM25 gene was found at 6h in head kidney and spleen, at 12h in liver, and at 24h in peripheral blood, demonstrating that the TRIM25 gene might play a key role in the antiviral immune response of large yellow croaker. This study provides a theoretical basis for further understanding the antiviral immune mechanism of large yellow croaker.
2019, 43(6): 1197 -1202
doi: 10.7541/2019.141
Abstract:
In order to investigate the mechanism of autophagy in yellow catfish Pelteobagrus fulvidraco, we cloned P. fulvidraco LC3B (PfLC3B) and Beclin1 (PfBeclin1) genes that were 372 bp and 1344 bp, respectively, and constructed the plasmid pET32a(+)-PfLC3B and pET32a(+)-PfBeclin1 encoding recombinant PfLC3B and PfBeclin1 protein, respectively. The recombinant PfLC3B was highly purified by affinity chromatography, while the recombinant PfBeclin1 protein was highly purified under inclusion body conditions. The polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies were generated by immunizing Balb/C mouse with recombinant PfLC3B and PfBeclin1 protein, respectively. The results of western blot showed that the polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies could recognize recombinant and endogenous PfLC3B and PfBeclin1 protein, respectively. PfLC3 and PfBeclin1 were predominantly expressed in the liver, but not in the kidney and spleen. In conclusion, we generated polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies, which provided powerful tools to investigate the mechanism of autophagy in yellow catfish.
In order to investigate the mechanism of autophagy in yellow catfish Pelteobagrus fulvidraco, we cloned P. fulvidraco LC3B (PfLC3B) and Beclin1 (PfBeclin1) genes that were 372 bp and 1344 bp, respectively, and constructed the plasmid pET32a(+)-PfLC3B and pET32a(+)-PfBeclin1 encoding recombinant PfLC3B and PfBeclin1 protein, respectively. The recombinant PfLC3B was highly purified by affinity chromatography, while the recombinant PfBeclin1 protein was highly purified under inclusion body conditions. The polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies were generated by immunizing Balb/C mouse with recombinant PfLC3B and PfBeclin1 protein, respectively. The results of western blot showed that the polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies could recognize recombinant and endogenous PfLC3B and PfBeclin1 protein, respectively. PfLC3 and PfBeclin1 were predominantly expressed in the liver, but not in the kidney and spleen. In conclusion, we generated polyclonal anti-PfLC3B and anti-PfBeclin1 antibodies, which provided powerful tools to investigate the mechanism of autophagy in yellow catfish.
2019, 43(6): 1203 -1209
doi: 10.7541/2019.142
Abstract:
To examine the molecular regulatory mechanism of microRNAs and target genes in Litopenaeus vannamei during cold adaptation, we conducted microRNAs (miRNAs) analysis on the hepatopancreas of L. vannamei under normal temperature of 28℃ and cold acclimation (16℃ for 6 days) by using Solexa sequencing. In total, 10690259 and 8587144 unique sequences of 18—32 nt length were obtained from small RNA libraries at room temperature and low temperature, including 57 and 48 known mature miRNAs, respectively. Expression analysis revealed 25 significantly differential expressed miRNAs between groups, and three of them were further confirmed by PCR. Moreover, we also observed that cold regulated target genes of significantly differential expressed miRNAs including the nuclear export mediator factor Nemf-lik, synapse-associated protein, seleno proteins and DEAD-box RNA helicase Variant 1. These results suggest that miRNAs and their target genes may mediate the cold adaption in L. vannamei.
To examine the molecular regulatory mechanism of microRNAs and target genes in Litopenaeus vannamei during cold adaptation, we conducted microRNAs (miRNAs) analysis on the hepatopancreas of L. vannamei under normal temperature of 28℃ and cold acclimation (16℃ for 6 days) by using Solexa sequencing. In total, 10690259 and 8587144 unique sequences of 18—32 nt length were obtained from small RNA libraries at room temperature and low temperature, including 57 and 48 known mature miRNAs, respectively. Expression analysis revealed 25 significantly differential expressed miRNAs between groups, and three of them were further confirmed by PCR. Moreover, we also observed that cold regulated target genes of significantly differential expressed miRNAs including the nuclear export mediator factor Nemf-lik, synapse-associated protein, seleno proteins and DEAD-box RNA helicase Variant 1. These results suggest that miRNAs and their target genes may mediate the cold adaption in L. vannamei.
2019, 43(6): 1210 -1215
doi: 10.7541/2019.143
Abstract:
dThe DMRT1 (double sex and mab-3 related transcription factor 1) is a highly conserved transcriptional regulator to play important role in sex determination and differentiation in most species ranging from nematodes to mammals. In this study, we cloned the cDNA sequence of
dThe DMRT1 (double sex and mab-3 related transcription factor 1) is a highly conserved transcriptional regulator to play important role in sex determination and differentiation in most species ranging from nematodes to mammals. In this study, we cloned the cDNA sequence of
2019, 43(6): 1216 -1223
doi: 10.7541/2019.144
Abstract:
To quickly and effectively distinguish different families and pedigrees of Coreius guichenoti, the present study screened twenty microsatellite loci with high polymorphism and stable amplification from the reported forty microsatellite loci using 339 individuals from eight families of C. guichenoti. Through this study, a paternity technology combined with fluorescent microsatellites and multiple capillary electrophoresis in C. guichenoti were established. Genetic diversity analysis revealed that the average allele number (Na) of eight families of C. guichenoti, the average polymorphism information content (PIC), the average expected heterozygosity (He), and the average observed heterozygosity (Ho) were 9, 0.616, 0.659, and 0.691, respectively. Genetic diversity indices of the offspring group were significantly lower than those of the parent group. Parentage analysis revealed that the combined exclusion probability of a first candidate parent given only the genotype of the offspring (CE-1P), a second candidate parent given the genotype of the offspring and one known parent (CE-2P) and a candidate parent poor give only the genotype of the offspring (CE-PP) were 0.99954473, 0.99999825 and 1.00000000, respectively, indicating that the accurate rate of parentage assignment was 100%. Thus we established a reliable paternity technology of C. guichenoti, which can provide scientific basis for its genealogical management, population genetic management, and assessment of stock enhancement effect.
To quickly and effectively distinguish different families and pedigrees of Coreius guichenoti, the present study screened twenty microsatellite loci with high polymorphism and stable amplification from the reported forty microsatellite loci using 339 individuals from eight families of C. guichenoti. Through this study, a paternity technology combined with fluorescent microsatellites and multiple capillary electrophoresis in C. guichenoti were established. Genetic diversity analysis revealed that the average allele number (Na) of eight families of C. guichenoti, the average polymorphism information content (PIC), the average expected heterozygosity (He), and the average observed heterozygosity (Ho) were 9, 0.616, 0.659, and 0.691, respectively. Genetic diversity indices of the offspring group were significantly lower than those of the parent group. Parentage analysis revealed that the combined exclusion probability of a first candidate parent given only the genotype of the offspring (CE-1P), a second candidate parent given the genotype of the offspring and one known parent (CE-2P) and a candidate parent poor give only the genotype of the offspring (CE-PP) were 0.99954473, 0.99999825 and 1.00000000, respectively, indicating that the accurate rate of parentage assignment was 100%. Thus we established a reliable paternity technology of C. guichenoti, which can provide scientific basis for its genealogical management, population genetic management, and assessment of stock enhancement effect.
2019, 43(6): 1224 -1230
doi: 10.7541/2019.145
Abstract:
Sinogastromyzon sichangensis is a small-size fish endemic to the upper Yangtze River mainly distributed in main stream and tributaries. Twenty-nine polymorphic microsatellite loci of the S. sichangensis were isolated by next-generation sequencing techniques. Four wild populations in Chishui River were amplified by 20 loci with mean alleles 14.5. The mean observed (Ho) and expected (He) heterozygosity were 0.620 and 0.882, respectively and the mean polymorphic information content (PIC) was 0.859. The Ho ranged from 0.520 (Maotai Town) to 0.669 (Chishui Town) and PIC ranged from 0.841 (Maotai Town) to 0.868 (Xishui River). The Fst value and analysis of population structure revealed a genetic differentiation between populations from Xishui River and the main stream of Chishui River. AMOVA showed that the genetic variation was 3.33% among populations while it was 96.67% within populations. These novel loci could use to investigate the population genetics and biological resource conservation strategy in S. sichangensis.
Sinogastromyzon sichangensis is a small-size fish endemic to the upper Yangtze River mainly distributed in main stream and tributaries. Twenty-nine polymorphic microsatellite loci of the S. sichangensis were isolated by next-generation sequencing techniques. Four wild populations in Chishui River were amplified by 20 loci with mean alleles 14.5. The mean observed (Ho) and expected (He) heterozygosity were 0.620 and 0.882, respectively and the mean polymorphic information content (PIC) was 0.859. The Ho ranged from 0.520 (Maotai Town) to 0.669 (Chishui Town) and PIC ranged from 0.841 (Maotai Town) to 0.868 (Xishui River). The Fst value and analysis of population structure revealed a genetic differentiation between populations from Xishui River and the main stream of Chishui River. AMOVA showed that the genetic variation was 3.33% among populations while it was 96.67% within populations. These novel loci could use to investigate the population genetics and biological resource conservation strategy in S. sichangensis.
2019, 43(6): 1231 -1238
doi: 10.7541/2019.146
Abstract:
The yield of hybrid yellow catfish (Pelteobagrus fulvidraco♀×Pelteobaggrus vachelli♂) was gradually increased, but the basic research is rarely. In this study, a comparative analysis of morphology and gonad development of yellow catfish (Pelteobagrus fulvidraco) and hybrid yellow catfish " Huangyou No. 1” at 3 various ages was conducted. The hybrid yellow catfish has a growth advantage to yellow catfish. 22-month and 34-month-old yellow male catfish weight twice as much as females. However, sexual size dimorphism was greatly reduced in the hybrid yellow catfish. Completely degenerated ovarian with a fine line structure and no egg production were observed in female hybrid yellow catfish, indicating that the female hybrid yellow catfish is completely sterile. Testes of male hybrid yellow catfish were transparent and degenerated. The spermatogenic cyst was almost empty and had no sperm production in 10-month-old male hybrid yellow catfish, while a few sperms were observed in the spermatogenic cyst of 22-month- and 34-month-old male hybrid yellow catfish. Compared to yellow catfish, the number of sperms of hybrid yellow catfish were very small and their activities were low based on computer assisted spermatozoa analysis system (CASA). In addition, 22-month-old male hybrid yellow catfish has no reproductive capacity. The novel variety " Huangyou No. 1” has a hybrid advantage in growth performance and is expected to promote the development of yellow catfish industry.
The yield of hybrid yellow catfish (Pelteobagrus fulvidraco♀×Pelteobaggrus vachelli♂) was gradually increased, but the basic research is rarely. In this study, a comparative analysis of morphology and gonad development of yellow catfish (Pelteobagrus fulvidraco) and hybrid yellow catfish " Huangyou No. 1” at 3 various ages was conducted. The hybrid yellow catfish has a growth advantage to yellow catfish. 22-month and 34-month-old yellow male catfish weight twice as much as females. However, sexual size dimorphism was greatly reduced in the hybrid yellow catfish. Completely degenerated ovarian with a fine line structure and no egg production were observed in female hybrid yellow catfish, indicating that the female hybrid yellow catfish is completely sterile. Testes of male hybrid yellow catfish were transparent and degenerated. The spermatogenic cyst was almost empty and had no sperm production in 10-month-old male hybrid yellow catfish, while a few sperms were observed in the spermatogenic cyst of 22-month- and 34-month-old male hybrid yellow catfish. Compared to yellow catfish, the number of sperms of hybrid yellow catfish were very small and their activities were low based on computer assisted spermatozoa analysis system (CASA). In addition, 22-month-old male hybrid yellow catfish has no reproductive capacity. The novel variety " Huangyou No. 1” has a hybrid advantage in growth performance and is expected to promote the development of yellow catfish industry.
2019, 43(6): 1239 -1245
doi: 10.7541/2019.147
Abstract:
In order to identify the morphological differences and discrimination of Acipenser baerii and Acipenser schrenckii, the hybrids of A. baerii♀× A. schrenckii♂ were analyzed by morphological and multivariate morphometric methods. There were significant differences in the number of gill rakes and dorsal fins among the countable traits of A. baerii, A. schrenckii and their hybrids. The multiple comparative analysis of the countable traits showed that the eye spacing/full length of A. baerii and A. schrenckii was significantly longer than that of their hybrids. The three principal components were extracted by principal component analysis, and the cumulative contribution rate to variation was 65.68%. The discriminant formulas for A. baerii, A. schrenckii and their hybrids were constructed by discriminant analysis, and the overall accuracy of the discriminant formulas was 85.6%. The results revealed that the morphological differences among A. baerii, A. schrenckii and their hybrids were mainly reflected in the head and tail stalk.
In order to identify the morphological differences and discrimination of Acipenser baerii and Acipenser schrenckii, the hybrids of A. baerii♀× A. schrenckii♂ were analyzed by morphological and multivariate morphometric methods. There were significant differences in the number of gill rakes and dorsal fins among the countable traits of A. baerii, A. schrenckii and their hybrids. The multiple comparative analysis of the countable traits showed that the eye spacing/full length of A. baerii and A. schrenckii was significantly longer than that of their hybrids. The three principal components were extracted by principal component analysis, and the cumulative contribution rate to variation was 65.68%. The discriminant formulas for A. baerii, A. schrenckii and their hybrids were constructed by discriminant analysis, and the overall accuracy of the discriminant formulas was 85.6%. The results revealed that the morphological differences among A. baerii, A. schrenckii and their hybrids were mainly reflected in the head and tail stalk.
2019, 43(6): 1246 -1252
doi: 10.7541/2019.148
Abstract:
In order to meet the demands of mandarin fish culture in different regions and seasons, and to achieve the requirement of fingerling supply of a balanced marketing, in this study, two batches broodstock were alternate artificial induced for 4 times in different seasons, and established a seed breeding mode of fry and fingerling breeding by month. The results showed there were 4 peaks of gonadasomatic index for broodstock cultivated in the cage after 4 times of artificial spawning, while broodstock naturally cultivated in pond showed only 2 peaks of gonadasomatic index. The total spawning eggs and hatching fry quantity of artificial propagation were positively correlated with the peak of gonadasomatic index. The gonadasomatic index, total spawning eggs and hatching fry quantity of second artificial propagation were the highest, which were significantly higher than the other three times (P<0.05). The fertilization rate, incubation rate, fry and fingerling survival rates in of the second, third and fourth propagation were significantly higher than those in first propagation (P<0.05). The temperature was the main factor affecting fertilization rate, incubation rate, fry and fingerling culture survival rate. The survival rate of induced broodstock decreased with the increaseding artificial propagation frequency. The survival rate of first propagation was up to 93.33%, significantly higher than that of third and fourth propagation (P<0.05). To sum up, it was feasible to solve the balanced supply of fingerling in mandarin fish by the modes of artificial breeding by seasonal echelon. This provides a scientific basis for changing culture mode of mandarin fish, and also has important referential significance for balanced supply of fingerling in other species.In summary, the results show that it is feasible to solve the balanced supply of seedling production by the artificial breeding mode according to the seasons. This provides a scientific basis for the changing culture mode of mandarin fish, and also provides a reference for the balanced production of other fish species.
In order to meet the demands of mandarin fish culture in different regions and seasons, and to achieve the requirement of fingerling supply of a balanced marketing, in this study, two batches broodstock were alternate artificial induced for 4 times in different seasons, and established a seed breeding mode of fry and fingerling breeding by month. The results showed there were 4 peaks of gonadasomatic index for broodstock cultivated in the cage after 4 times of artificial spawning, while broodstock naturally cultivated in pond showed only 2 peaks of gonadasomatic index. The total spawning eggs and hatching fry quantity of artificial propagation were positively correlated with the peak of gonadasomatic index. The gonadasomatic index, total spawning eggs and hatching fry quantity of second artificial propagation were the highest, which were significantly higher than the other three times (P<0.05). The fertilization rate, incubation rate, fry and fingerling survival rates in of the second, third and fourth propagation were significantly higher than those in first propagation (P<0.05). The temperature was the main factor affecting fertilization rate, incubation rate, fry and fingerling culture survival rate. The survival rate of induced broodstock decreased with the increaseding artificial propagation frequency. The survival rate of first propagation was up to 93.33%, significantly higher than that of third and fourth propagation (P<0.05). To sum up, it was feasible to solve the balanced supply of fingerling in mandarin fish by the modes of artificial breeding by seasonal echelon. This provides a scientific basis for changing culture mode of mandarin fish, and also has important referential significance for balanced supply of fingerling in other species.In summary, the results show that it is feasible to solve the balanced supply of seedling production by the artificial breeding mode according to the seasons. This provides a scientific basis for the changing culture mode of mandarin fish, and also provides a reference for the balanced production of other fish species.
2019, 43(6): 1253 -1261
doi: 10.7541/2019.149
Abstract:
To investigate the impact of water flow on fish phototaxis, this study tested the light preference behavior of juvenile grass carp (Ctenpharyngodon idellus), adopting a self-made recirculating channel, under 300 lx light source with three velocity treatments (0, 0.1 m/s and 0.2 m/s respectively) and control group (dark, still water). The results indicated that the flow velocity of 0.2 m/s was able to adequately stimulate the rheotaxis of grass carp juveniles, constraining the dominant swimming direction within ± 20° from the opposite direction of flow. According to the distribution of juvenile grass carps in the test channel with light intensity attenuation, the illumination expectations of test fish at the three given velocity levels were 52.45 lx, 34.62 lx, and 37.86 lx respectively. During the 300 lx trial, fish in still water displayed high distribution on the lateral sides and low distribution in the middle of the channel without a preference for any specific range of light intensities. At the low-velocity level less than the induced value, the overall distribution of juvenile grass carp was similar to that in still water, but farther away from the light source, and more individuals performed " reverse flow backwards” behavior. When the flow velocity surpassed the induced value, the accumulation of fish on the rear side reduced due to the effect of the rheotaxis, and the distribution was more uniform, and the light environment influence is reduced. This study demonstrated that grass carp rheotaxis caused by a small flow velocity, which is slightly larger than the induction value, could affect its light environment response behavior.
To investigate the impact of water flow on fish phototaxis, this study tested the light preference behavior of juvenile grass carp (Ctenpharyngodon idellus), adopting a self-made recirculating channel, under 300 lx light source with three velocity treatments (0, 0.1 m/s and 0.2 m/s respectively) and control group (dark, still water). The results indicated that the flow velocity of 0.2 m/s was able to adequately stimulate the rheotaxis of grass carp juveniles, constraining the dominant swimming direction within ± 20° from the opposite direction of flow. According to the distribution of juvenile grass carps in the test channel with light intensity attenuation, the illumination expectations of test fish at the three given velocity levels were 52.45 lx, 34.62 lx, and 37.86 lx respectively. During the 300 lx trial, fish in still water displayed high distribution on the lateral sides and low distribution in the middle of the channel without a preference for any specific range of light intensities. At the low-velocity level less than the induced value, the overall distribution of juvenile grass carp was similar to that in still water, but farther away from the light source, and more individuals performed " reverse flow backwards” behavior. When the flow velocity surpassed the induced value, the accumulation of fish on the rear side reduced due to the effect of the rheotaxis, and the distribution was more uniform, and the light environment influence is reduced. This study demonstrated that grass carp rheotaxis caused by a small flow velocity, which is slightly larger than the induction value, could affect its light environment response behavior.
2019, 43(6): 1262 -1270
doi: 10.7541/2019.150
Abstract:
As a warm-water species, changes of aquatic environment caused by global climate change could affect the distribution of Pelteobagrus fulvidraco natural resources. To investigate this (the distribution of this species in current, 2050s, and 2070s), three general circulation models (BCC-CSM1-1, CCSM4, and MRI-CGCM3), two greenhouse gas emission scenarios (RCP2.6 and RCP8.5) and random forest, an ensemble modeling, were used based on the distribution information of this species. The results indicated that the Area Under the Curve (AUC) of the prediction model reached 0.971, indicating a good generalization and great reliability; The mean temperature of wettest quarter and max temperature of warmest month were the most important environmental factors to predict the distribution of P. fulvidraco evaluated by node purity; The main habitat of P. fulvidraco would gradually depart from the eastern and middle areas in China and expand to the north, and the area of most suitable habitat would gradually decrease under the future climate change conditions. Research on the distribution of P. fulvidraco and the main ecological conditions affecting its distribution has the practical significance to delineation of germplasm reserves of P. fulvidraco, fishery management, and prevention and control for potential biological invasion, as well as provide a reference basis for the response of other freshwater fishes in East Asia to climate change.
As a warm-water species, changes of aquatic environment caused by global climate change could affect the distribution of Pelteobagrus fulvidraco natural resources. To investigate this (the distribution of this species in current, 2050s, and 2070s), three general circulation models (BCC-CSM1-1, CCSM4, and MRI-CGCM3), two greenhouse gas emission scenarios (RCP2.6 and RCP8.5) and random forest, an ensemble modeling, were used based on the distribution information of this species. The results indicated that the Area Under the Curve (AUC) of the prediction model reached 0.971, indicating a good generalization and great reliability; The mean temperature of wettest quarter and max temperature of warmest month were the most important environmental factors to predict the distribution of P. fulvidraco evaluated by node purity; The main habitat of P. fulvidraco would gradually depart from the eastern and middle areas in China and expand to the north, and the area of most suitable habitat would gradually decrease under the future climate change conditions. Research on the distribution of P. fulvidraco and the main ecological conditions affecting its distribution has the practical significance to delineation of germplasm reserves of P. fulvidraco, fishery management, and prevention and control for potential biological invasion, as well as provide a reference basis for the response of other freshwater fishes in East Asia to climate change.
2019, 43(6): 1271 -1279
doi: 10.7541/2019.151
Abstract:
This study investigated growth performance and hypoxia tolerant ability of the yellow catfish and the hybrid catfish called " Huangyou No. 1” for an 8-week trial. The results showed that the average weight of the hybrid catfish was (19.60±0.88) g/tail at week 8, which was significantly higher than that of the yellow catfish was (15.74±0.42) g/tail (P<0.05) with a 24.52% increase. The feed coefficient of the hybrid catfish and the yellow catfish were 1.18±0.14 and 1.36±0.21, respectively. The survival rate of young hybrids catfish was 87.78±1.92, which was significantly higher than that of the yellow catfish at 67.78±1.92 (P<0.05). The survival rate of the hybrid catfish was 29.51% higher than that of the yellow catfish. The hybrid catfish and yellow catfish were placed in water with dissolved oxygen content of (1.48±0.27) mg/L and then hypoxia stress for 0, 6h, 12h and 24h before collecting serum and liver for measurements. Hypoxia stress significantly regulated the LDH activity, SOD activity, CAT activity at 6h and the T-AOC at 12h in the serum and liver of both hybrid catfish and yellow catfish (P<0.05). The brain and liver HIF-1α mRNA level of both hybrid catfish and yellow catfish increased significantly by hypoxic stress (P<0.05) with higher level in hybrid catfish at 6h, 12h and 24h. These results indicated that long-term hypoxic stress may cause oxidative damage to hybrid catfish and yellow catfish, but hypoxia tolerance of hybrid catfish is higher than that of yellow catfish.
This study investigated growth performance and hypoxia tolerant ability of the yellow catfish and the hybrid catfish called " Huangyou No. 1” for an 8-week trial. The results showed that the average weight of the hybrid catfish was (19.60±0.88) g/tail at week 8, which was significantly higher than that of the yellow catfish was (15.74±0.42) g/tail (P<0.05) with a 24.52% increase. The feed coefficient of the hybrid catfish and the yellow catfish were 1.18±0.14 and 1.36±0.21, respectively. The survival rate of young hybrids catfish was 87.78±1.92, which was significantly higher than that of the yellow catfish at 67.78±1.92 (P<0.05). The survival rate of the hybrid catfish was 29.51% higher than that of the yellow catfish. The hybrid catfish and yellow catfish were placed in water with dissolved oxygen content of (1.48±0.27) mg/L and then hypoxia stress for 0, 6h, 12h and 24h before collecting serum and liver for measurements. Hypoxia stress significantly regulated the LDH activity, SOD activity, CAT activity at 6h and the T-AOC at 12h in the serum and liver of both hybrid catfish and yellow catfish (P<0.05). The brain and liver HIF-1α mRNA level of both hybrid catfish and yellow catfish increased significantly by hypoxic stress (P<0.05) with higher level in hybrid catfish at 6h, 12h and 24h. These results indicated that long-term hypoxic stress may cause oxidative damage to hybrid catfish and yellow catfish, but hypoxia tolerance of hybrid catfish is higher than that of yellow catfish.
2019, 43(6): 1280 -1289
doi: 10.7541/2019.152
Abstract:
Exposure to water samples collected from a river located in a pharmaceutical industry park in Eastern China resulted in some extent of death for zebrafish. A target screening method involving 248 compounds was employed to reveal the main poisonous chemical factors in these water samples. Twenty four compounds were identified including 17 pharmaceuticals such as mirtazapine and desloratadine. However, no positive relationship was observed between the residual levels of these compounds and death rates of zebrafish. The results suggest that the compounds identified in the water samples were not the main poisonous contributors for the aquatic health risk in the river.
Exposure to water samples collected from a river located in a pharmaceutical industry park in Eastern China resulted in some extent of death for zebrafish. A target screening method involving 248 compounds was employed to reveal the main poisonous chemical factors in these water samples. Twenty four compounds were identified including 17 pharmaceuticals such as mirtazapine and desloratadine. However, no positive relationship was observed between the residual levels of these compounds and death rates of zebrafish. The results suggest that the compounds identified in the water samples were not the main poisonous contributors for the aquatic health risk in the river.
2019, 43(6): 1290 -1299
doi: 10.7541/2019.153
Abstract:
This study analyzed the effects of dissolved oxygen content (DOC) and water temperature on the community and richness of bacteria in In-pond Raceway System (IPRS) from various viewpoints using Illumina Miseq high-throughput sequencing technology. The highest and lowest microbial richness was in September and October, respectively. In general, the microbial richness in lowest DOC was greater than that in highest DOC during the diurnal variation. The microbial richness in fecal collecting area was greater than that in aquaculture area. Proteobacteria, Actinobacteria, Bacteroidetes and Cyanobacteria were the 4 dominant species among July and November. At generic levels, Pseudomonas, Synechococcus and Flarobacterium were dominant species. Almost every bacterium had significant or extremely significant difference among different months. The richness of Pseudomonas was positively correlated to DOC (r=0.415, P<0.01), but negatively correlated to water temperature (r=–0.427, P<0.01). There was a significant correlation between Synechococcus, Cyanobacteria, CL500-29, Alpinimonas and water temperature (r=0.636, –0.448, 0.755, –0.428 respectively, P<0.01). The richness of Mycobacterium (r=0.488, P<0.01) and MNG7 were significantly correlated to DOC. Furthermore, there were significant or extremely significant relations among different bacterial communities. The microbial richness increased with the decreasing DOC level to reach peak level at 2.5 mg/L of DOC. These results suggest that stocking density, culture area, DOC, and season variety could regulate microbial richness.
This study analyzed the effects of dissolved oxygen content (DOC) and water temperature on the community and richness of bacteria in In-pond Raceway System (IPRS) from various viewpoints using Illumina Miseq high-throughput sequencing technology. The highest and lowest microbial richness was in September and October, respectively. In general, the microbial richness in lowest DOC was greater than that in highest DOC during the diurnal variation. The microbial richness in fecal collecting area was greater than that in aquaculture area. Proteobacteria, Actinobacteria, Bacteroidetes and Cyanobacteria were the 4 dominant species among July and November. At generic levels, Pseudomonas, Synechococcus and Flarobacterium were dominant species. Almost every bacterium had significant or extremely significant difference among different months. The richness of Pseudomonas was positively correlated to DOC (r=0.415, P<0.01), but negatively correlated to water temperature (r=–0.427, P<0.01). There was a significant correlation between Synechococcus, Cyanobacteria, CL500-29, Alpinimonas and water temperature (r=0.636, –0.448, 0.755, –0.428 respectively, P<0.01). The richness of Mycobacterium (r=0.488, P<0.01) and MNG7 were significantly correlated to DOC. Furthermore, there were significant or extremely significant relations among different bacterial communities. The microbial richness increased with the decreasing DOC level to reach peak level at 2.5 mg/L of DOC. These results suggest that stocking density, culture area, DOC, and season variety could regulate microbial richness.
THE COMMUNITY CHARACTERISTICS OF LARVAE AND JUVENILE FISH IN THE ANQING SECTION OF THE YANGTZE RIVER
2019, 43(6): 1300 -1310
doi: 10.7541/2019.154
Abstract:
Anqing section is one of the important fishery resources waters in the lower reaches of the Yangtze River. To understand assemblage characteristics of larvae and juveniles fish and their correlation with environmental factors, the early fish resources in Anqing section were investigated day by day from April 17 to August 15, 2016. The results revealed that a total of 92160 larvae or juveniles were captured, and 90457 were identified, belonging to 7 orders, 13 families and 49 species, while Cyprinidae was the largest family including 32 species, accounting for 90.16% of the total number of tails; Gobiidae was the second largest family including 3 species, accounting for 5.71% of the total number of tails. As for ecological type and spawning type, fishery residents fishes and fishes with pelagic eggs accounted for the largest proportions of 87.57% and 88.30%, respectively. Hemiculter bleekeri (44.53%) was the largest dominant species in this section and the other dominant species were Hemiculter leucisculus (14.21%), Xenocypris argentea (8.11%), Rhinogobius giurinus (5.60%), Pseudolaubuca sinensis (4.75%), Pseudobrama simoni (4.13%), Pseudolaubuca engraulis (4.50%), Parabramis pekinensis (2.63%), Coilia nasus (1.89%) and Hypophthalmichthys molitrix (1.57%). Larvae or juveniles abundances have four obvious outbreak period with the first period on the 1st May and the other three in the mid to late June, which were 1127.00, 1608.44, 1568.44, 1202.94 ind./100 m3, respectively. Redundancy analysis (RDA) revealed that the main environmental factors affecting the abundance of larval and juvenile fish in Anqing river section are water flow, water level and transparency (P<0.05). The abundance of most larval and juvenile fish were negatively correlated with water flow and water level, and positively correlated with transparency, which may explain by the excessive water flow and water level in that year. This study demonstrated that Anqing section was abundant of diverse species of early fish resources which mainly consisted of small fish, and the proportion of economic juvenile fish is small. These results provide basic information for the formulation of protection policy on Anqing fishery resources with scientific reference.
Anqing section is one of the important fishery resources waters in the lower reaches of the Yangtze River. To understand assemblage characteristics of larvae and juveniles fish and their correlation with environmental factors, the early fish resources in Anqing section were investigated day by day from April 17 to August 15, 2016. The results revealed that a total of 92160 larvae or juveniles were captured, and 90457 were identified, belonging to 7 orders, 13 families and 49 species, while Cyprinidae was the largest family including 32 species, accounting for 90.16% of the total number of tails; Gobiidae was the second largest family including 3 species, accounting for 5.71% of the total number of tails. As for ecological type and spawning type, fishery residents fishes and fishes with pelagic eggs accounted for the largest proportions of 87.57% and 88.30%, respectively. Hemiculter bleekeri (44.53%) was the largest dominant species in this section and the other dominant species were Hemiculter leucisculus (14.21%), Xenocypris argentea (8.11%), Rhinogobius giurinus (5.60%), Pseudolaubuca sinensis (4.75%), Pseudobrama simoni (4.13%), Pseudolaubuca engraulis (4.50%), Parabramis pekinensis (2.63%), Coilia nasus (1.89%) and Hypophthalmichthys molitrix (1.57%). Larvae or juveniles abundances have four obvious outbreak period with the first period on the 1st May and the other three in the mid to late June, which were 1127.00, 1608.44, 1568.44, 1202.94 ind./100 m3, respectively. Redundancy analysis (RDA) revealed that the main environmental factors affecting the abundance of larval and juvenile fish in Anqing river section are water flow, water level and transparency (P<0.05). The abundance of most larval and juvenile fish were negatively correlated with water flow and water level, and positively correlated with transparency, which may explain by the excessive water flow and water level in that year. This study demonstrated that Anqing section was abundant of diverse species of early fish resources which mainly consisted of small fish, and the proportion of economic juvenile fish is small. These results provide basic information for the formulation of protection policy on Anqing fishery resources with scientific reference.
2019, 43(6): 1311 -1320
doi: 10.7541/2019.155
Abstract:
In order to understand the status of fish resources in Shaanxi Province of the Weihe River, we conducted a survey on fish resources in the Shaanxi section of the Weihe River in four times from 2016 to 2017. A total of 49 species of fish were investigated, which belong to 6 orders, 11 families, 36 genera. The dominant species were Gnathopogon imberbis, Rhynchocypris lagowskii, Abbottina rivularis, Hemiculter leucisculus, Cyprinus carpio and Hypophthalmichthys molitrix. Compared with the results of the survey in 1984, 36 species of fish were reduced with a significant decrease of the variety of species. The similarity index of species composition between two investigations was 0.49, representing a medium dissimilarity. According to Shannon-Wiener index, Pielou’s index, Marglef index, Jaccard’s index and G-F index, the composition of fishes community was obviously changed in the Weihe River of Shaanxi section, and the species diversity decreased by 60%. The analysis of the individual ecology type indicated that the community structure in Weihe Shaanxi section has changed greatly, which are mainly composed of slow flow, omnivorous type, and inhabiting gravel substratum group. The results indicated that the diversity of fish species and the amount of fish resources in the river have decreased significantly, which may explain by the water pollution, decreased water resources and reduced habitat suitability.
In order to understand the status of fish resources in Shaanxi Province of the Weihe River, we conducted a survey on fish resources in the Shaanxi section of the Weihe River in four times from 2016 to 2017. A total of 49 species of fish were investigated, which belong to 6 orders, 11 families, 36 genera. The dominant species were Gnathopogon imberbis, Rhynchocypris lagowskii, Abbottina rivularis, Hemiculter leucisculus, Cyprinus carpio and Hypophthalmichthys molitrix. Compared with the results of the survey in 1984, 36 species of fish were reduced with a significant decrease of the variety of species. The similarity index of species composition between two investigations was 0.49, representing a medium dissimilarity. According to Shannon-Wiener index, Pielou’s index, Marglef index, Jaccard’s index and G-F index, the composition of fishes community was obviously changed in the Weihe River of Shaanxi section, and the species diversity decreased by 60%. The analysis of the individual ecology type indicated that the community structure in Weihe Shaanxi section has changed greatly, which are mainly composed of slow flow, omnivorous type, and inhabiting gravel substratum group. The results indicated that the diversity of fish species and the amount of fish resources in the river have decreased significantly, which may explain by the water pollution, decreased water resources and reduced habitat suitability.
2019, 43(6): 1321 -1332
doi: 10.7541/2019.156
Abstract:
This study analyzed the distribution patterns and seasonal variation of zooplankton, and the effects of the water masses based on the data collected from four oceanographic surveys in the coastal waters of northern Fujian (120.10°E—120.65°E, 26.35°N—27.07°N) during the summer, autumn, winter and spring from 2015 to 2016, we analyzed the distribution patterns and seasonal variation of zooplankton, and the effects of the water masses. The results indicated that the average biomass of zooplankton was was followed as summer (479.51 mg/m3)>autumn (257.37 mg/m3)>spring (241.86 mg/m3)>winter (84.05 mg/m3), and the average abundance of zooplankton was was followed as summer (156.36 ind./m3)>spring (91.57 ind./m3)>autumn (40.34 ind./m3)>winter (21.82 ind./m3). The average biomass and the abundance of zooplankton both decreased from summer, autumn to winter in turn, while increased in spring. The average biomass in autumn was higher than that in the spring, on the contrary, the average abundance was lower than that in the spring. In summer, winter and spring, the distribution of total biomass and total abundance of zooplankton were generally consistent. While in autumn, the distribution patterns were almost in the opposite direction. Sagitta bedoti and Canthocalanus pauper were the most important species which had impact onregulating the distribution of total abundance in summer, and Desmophyes annectens was the most important species for the distribution of total abundance in autumn. In winter, Acrocalanus gibber, Eucalanus subcrassus and Sagitta bedoti had an important impact onmainly mediated the distribution of total abundance. Muggiaea atlantica and Canthocalanus pauper were the two species that had a higher proportion of total abundance in spring. The seasonal variation of the Taiwan warm current and Zhe-Min coastal current was the root factor that decidedto decide the distribution patterns of zooplankton in each season. The results not only had an important theoretical significance for understanding and evaluating the dynamics of regional marine ecosystem and biodiversity changes, but also could improved the relationship between the ecological characteristics of zooplankton and water mass changes in China’s offshore waters.
This study analyzed the distribution patterns and seasonal variation of zooplankton, and the effects of the water masses based on the data collected from four oceanographic surveys in the coastal waters of northern Fujian (120.10°E—120.65°E, 26.35°N—27.07°N) during the summer, autumn, winter and spring from 2015 to 2016, we analyzed the distribution patterns and seasonal variation of zooplankton, and the effects of the water masses. The results indicated that the average biomass of zooplankton was was followed as summer (479.51 mg/m3)>autumn (257.37 mg/m3)>spring (241.86 mg/m3)>winter (84.05 mg/m3), and the average abundance of zooplankton was was followed as summer (156.36 ind./m3)>spring (91.57 ind./m3)>autumn (40.34 ind./m3)>winter (21.82 ind./m3). The average biomass and the abundance of zooplankton both decreased from summer, autumn to winter in turn, while increased in spring. The average biomass in autumn was higher than that in the spring, on the contrary, the average abundance was lower than that in the spring. In summer, winter and spring, the distribution of total biomass and total abundance of zooplankton were generally consistent. While in autumn, the distribution patterns were almost in the opposite direction. Sagitta bedoti and Canthocalanus pauper were the most important species which had impact onregulating the distribution of total abundance in summer, and Desmophyes annectens was the most important species for the distribution of total abundance in autumn. In winter, Acrocalanus gibber, Eucalanus subcrassus and Sagitta bedoti had an important impact onmainly mediated the distribution of total abundance. Muggiaea atlantica and Canthocalanus pauper were the two species that had a higher proportion of total abundance in spring. The seasonal variation of the Taiwan warm current and Zhe-Min coastal current was the root factor that decidedto decide the distribution patterns of zooplankton in each season. The results not only had an important theoretical significance for understanding and evaluating the dynamics of regional marine ecosystem and biodiversity changes, but also could improved the relationship between the ecological characteristics of zooplankton and water mass changes in China’s offshore waters.
2019, 43(6): 1333 -1345
doi: 10.7541/2019.157
Abstract:
To evaluate the water quality situation, this study investigated zooplankton species, density and biomass and the main water quality indexes like water temperature, conductivity, DO and pH in 12 cross-sections in the Wei River Basin in October of 2017 and June of 2018, respectively, using the biological diversity index method. 57 species of zooplankton species (11 species of protozoa, 33 species of rotifers, 7 species of cladocerans, 6 species of copepods) were identified, and the dominant species was Brachionus calyciflorus. During dry season, the density of zooplankton varied between 0.72—7.84 ind./L with the average density of (2.79±2.11) ind./L, and the biomass ranged from 0.38 to 6.15 mg/L with the average biomass of (2.31±2.64) mg/L. The diversity indices of Shannon-Wiener and Margalef were 1.07 and 0.69, respectively. The canonical correspondence analysis indicated that the community structure of zooplankton in the Wei River Basin was primarily affected by the water environment including temperature, DO, altitude and conductivity. During wet season, the density of zooplankton varied between 0—179.02 ind./L with an average density of (16.66±49.18) ind./L, and the biomass ranged 0—2448.12 mg/L with an average biomass of (243.96±673.78) mg/L. The diversity indices of Shannon-Wiener and Margalef were 0.78 and 1.15, respectivly. The water quality of Wei River in Beidao and Linjiacun was moderately polluted, and the water qualities in Weijiabao were heavy pollution, and in Xianyang, Lintong, Huaxian the water qualities were light pollution. The water quality of Jing River in Yangjiaping, Yuluoping and Zhangjiashan was moderately polluted. The water quality of Beiluo River in Liujiahe, Jiaokouhe and Zhuangtou was moderately polluted.
To evaluate the water quality situation, this study investigated zooplankton species, density and biomass and the main water quality indexes like water temperature, conductivity, DO and pH in 12 cross-sections in the Wei River Basin in October of 2017 and June of 2018, respectively, using the biological diversity index method. 57 species of zooplankton species (11 species of protozoa, 33 species of rotifers, 7 species of cladocerans, 6 species of copepods) were identified, and the dominant species was Brachionus calyciflorus. During dry season, the density of zooplankton varied between 0.72—7.84 ind./L with the average density of (2.79±2.11) ind./L, and the biomass ranged from 0.38 to 6.15 mg/L with the average biomass of (2.31±2.64) mg/L. The diversity indices of Shannon-Wiener and Margalef were 1.07 and 0.69, respectively. The canonical correspondence analysis indicated that the community structure of zooplankton in the Wei River Basin was primarily affected by the water environment including temperature, DO, altitude and conductivity. During wet season, the density of zooplankton varied between 0—179.02 ind./L with an average density of (16.66±49.18) ind./L, and the biomass ranged 0—2448.12 mg/L with an average biomass of (243.96±673.78) mg/L. The diversity indices of Shannon-Wiener and Margalef were 0.78 and 1.15, respectivly. The water quality of Wei River in Beidao and Linjiacun was moderately polluted, and the water qualities in Weijiabao were heavy pollution, and in Xianyang, Lintong, Huaxian the water qualities were light pollution. The water quality of Jing River in Yangjiaping, Yuluoping and Zhangjiashan was moderately polluted. The water quality of Beiluo River in Liujiahe, Jiaokouhe and Zhuangtou was moderately polluted.
2019, 43(6): 1346 -1352
doi: 10.7541/2019.158
Abstract:
Stylonychia lemnae is a monocyte eukaryote with animal nutrition. It is also an important model protozoa to study cytology and genetics. Sterile pure culture is an important basis for the study of Stylonychia biology. In order to build a high-efficiency pure cultured system for Stylonychia, a Tetrahymena thermophila sterile pure cultured medium was referenced in this paper. And a response surface analysis was used to carried out single-factor and orthogonal experiments focused on the ratio of nitrogen source, carbon source and dipotassium hydrogen phosphate. A sterile pure cultured medium for Stylonychia was primarily established and some key cultured conditions were optimized including cultured temperature, initial pH, medium volume and initial cell density. Results showed that the securable maximum cell amount was about 3.0×103 cells and the best conditions were initial amount 100 cells, medium volume 10 mL, initial pH 7.0 and the cultured temperature 25℃.
Stylonychia lemnae is a monocyte eukaryote with animal nutrition. It is also an important model protozoa to study cytology and genetics. Sterile pure culture is an important basis for the study of Stylonychia biology. In order to build a high-efficiency pure cultured system for Stylonychia, a Tetrahymena thermophila sterile pure cultured medium was referenced in this paper. And a response surface analysis was used to carried out single-factor and orthogonal experiments focused on the ratio of nitrogen source, carbon source and dipotassium hydrogen phosphate. A sterile pure cultured medium for Stylonychia was primarily established and some key cultured conditions were optimized including cultured temperature, initial pH, medium volume and initial cell density. Results showed that the securable maximum cell amount was about 3.0×103 cells and the best conditions were initial amount 100 cells, medium volume 10 mL, initial pH 7.0 and the cultured temperature 25℃.
2019, 43(6): 1353 -1361
doi: 10.7541/2019.159
Abstract:
The steady growth of submerged plants is an important factor for the reconstruction of healthy lake ecosystem, and the sediment conditions are also the key factors for the growth of submerged plants. This study explores the effects of medical stone on its physiological and ecological changes in submerged plants. The results showed that the medical stone significantly promoted the growth of Vallisneria natans. The height and biomass of Vallisneria natans covered with 1 cm thick medical stone were better compared with the lake sediment group (P<0.05), and the modified medical stone group was better than the raw stone group (P<0.05) to promote the height and biomass of Vallisneria natans. The photosynthetic pigment, root activity, malondialdehyde (MDA), peroxidase (POD) activity and other indicators of the two plants, Vallisneria natans and Hydrilla verticillata in medical stone group were better than those in the lake sediment group. The medical stone contained abundant constant and trace elements that are required for the growth of submerged plants. Thus, medical stone is beneficial to the growth of submerged plants and can be further applied to ecological restoration projects as sediment improvement material.
The steady growth of submerged plants is an important factor for the reconstruction of healthy lake ecosystem, and the sediment conditions are also the key factors for the growth of submerged plants. This study explores the effects of medical stone on its physiological and ecological changes in submerged plants. The results showed that the medical stone significantly promoted the growth of Vallisneria natans. The height and biomass of Vallisneria natans covered with 1 cm thick medical stone were better compared with the lake sediment group (P<0.05), and the modified medical stone group was better than the raw stone group (P<0.05) to promote the height and biomass of Vallisneria natans. The photosynthetic pigment, root activity, malondialdehyde (MDA), peroxidase (POD) activity and other indicators of the two plants, Vallisneria natans and Hydrilla verticillata in medical stone group were better than those in the lake sediment group. The medical stone contained abundant constant and trace elements that are required for the growth of submerged plants. Thus, medical stone is beneficial to the growth of submerged plants and can be further applied to ecological restoration projects as sediment improvement material.
Journal Introduction
- Establishment Time：1955 Bimonthly
- Competent unit：Chinese Academy of Sciences
- Host unit：Institute of Hydrobiology, Chinese Academy of Sciences ; Chinese Society for Oceanology and Limnology
- Editor-in-Chief：GUI Jian-Fang
- ISSN 1000-3207
- CN 42-1230/Q
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