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Available online   , doi: 10.7541/2019.059
[Abstract](227) [FullText HTML](91) [PDF 629KB](43)
Abstract:
To estimate the effects of Microcystin-LR (MC-LR) on the autophagy, we cloned Beclin1 CiBeclin1 gene from grass carp (Ctenopharygodon idella) using rapid amplification of cDNA ends (RACE) based on the EST sequence. The deduced amino acid sequence of CiBeclin1 was comprised of 447 amino acids, and CiBeclin1 possessed a typical Bcl-2 homology domain 3 (BH3) and an evolutionarily conserved domain (ECD). The similarity of CiBeclin1 amino acid sequence with other species was 88%—98%, and phylogenetic analysis demonstrated that CiBeclin1 formed a clade with rare minnow Beclin1. CiBeclin1 was ubiquitously expressed in 10 tested tissues, including the liver, kidney, spleen and others, with the highest level in liver. MC-LR significantly decreased the expression of CiBeclin1 at 24, 48, 72 and 96h, indicating that CiBeclin1 gene might play a regulatory role against MC-LR toxicity. However, whether the used doses of MC-LR could induce liver autophagy needs further investigation.
Available online   , doi: 10.7541/2019.056
[Abstract](87) [FullText HTML](22) [PDF 719KB](7)
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Nanos3 is one of the components of germ plasm which is generally considered to be the determinant of primordial germ cells (PGCs) in most of the ovipara. The miR430 bind to the 3′untranslated region (UTR) of nanos3 to mediate the degradation of its mRNA in somatic cells, while in PGCs, the Dnd1 binds to the 3′UTR region of nanos3 to protect it from degradation through miR430. Therefore, the 3′UTR of nanos3 was generally used to mediate the specific expression of fluorescent protein in PGCs. In this study, we cloned and characterized the cDNA of the nanos3 homolog in Megalobrama amblycephala (mananos3). Mananos3 is of 1027 bp length including 48 bp 5′UTR, 490bp 3′UTR and 489 bp opening reading frame. It encodes a peptide with 162aa. By peptide alignment, there was a conserved RNA binding domain with one zinc finger motif. Phylogenetic analysis revealed that Mananos3 has the highest similarity with its homolog in common carp. Semi-quantitative and Real-time qPCR showed that nananos3 was highly maternally expressed. During early embryonic stage, it was high expressed before 1k-cell stage and then gradually decreased. Mananos3 was specifically expressed in ovary among different selected tissues. Both 3′UTR of mananos3 and zebrafish nanos3 (zfnanos3) can mediate the specific expression of green fluorescent protein (EGFP) in PGCs while it appeared that 3′UTR of mananos3 has higher efficiency and specificity. Finally, the alignment of the 3′UTR of mananos3 and zfnanos3 revealed a potential non-classical recognition site (GCACTA) for miR430 that promotes the degradation of mRNA in non-PGCs tissues.
Available online   , doi: 10.7541/2019.062
[Abstract](105) [FullText HTML](36) [PDF 551KB](8)
Abstract:
To evaluate effects of stickwater, stickwater hydrolysate and fish protein hydrolysate to replace fish meal on the growth performance of yellow catfish (Pelteobagrus fulvidraco), ten isonitrogenous and isolipidic diets were formulated to feed 30 net cages of yellow catfish (18.68±0.10) g for 60 days. A semipurified diet containing 28% fish meal was formulated as a control (FM diet). Other nine non- fish meal diets were formulated with stickwater (SW15, SW30, SW45), stickwater hydrolysate (SWH15, SWH30, SWH45) or fish protein hydrolysate (FPH15, FPH30, FPH45), supplying approximate15%, 30% or 45% fish meal protein of FM diet. (1) Compared with diet FM, diets SW decreased SGR by 9.89%—20.33% (P<0.05, and increased FCR by 18.79%—44.85% (P<0.05). Diet SWH15 and diet SWH45 decreased SGR by 8.79% and 14.84% respectively and increased FCR by 16.97% and 27.88% compared with those of the diet FM (P<0.05). Diet FPH15 and diet FPH45 decreased SGR by 13.18% and 15.38%, and increased FCR by 30.30% and 29.70% compared with diet FM (P<0.05); (2) No significant difference was noticed among diet SWH30, diet FPH30 and diet FM in SGR and FCR (P>0.05); (3) The SGR of diets SWH additionally increased 4.40%—9.39% compared with diets SW, while the FCR decreased 9.81%—15.31% (P<0.05); (4) Compared with diet FM, the FIFO of diet SW30, SWH30 and FPH30 were 0.67, 0.61 and 0.60, respectively, decreased by 67.67% to 70.15% (P<0.05). These results indicated that 28% fish meal protein quality of 8.5% (with dry weight 90%) stickwater hydrolysate (diet SWH30) and 8.2% (with dry weight 90%) fish protein hydrolysate (diet FPH30) have similar growth performance with 28% fish meal in yellow catfish diet, and that the FIFO of these two diets were reduced by 69.95% and 70.15% compared with that of diet FM. The stickwater hydrolysate had better fish growth performance than stickwater. The growth performance and feed efficiency of yellow catfish were significantly decreased when the additive amount of stickwater and stickwater hydrolysate was not suitable.
Available online   , doi: 10.7541/2019.079
[Abstract](163) [FullText HTML](71) [PDF 695KB](15)
Abstract:
To explore the toxic effects of streptomycin, the growth and chlorophyll fluorescence were measured in Nostoc treated with different concentrations (0, 0.05, 0.10, 0.20, 0.50 and 1 mg/L) of streptomycin. The results indicated that the EC50 of streptomycin to Nostoc (96h-EC50) was (0.13±0.037) mg/L at the 96−hour. Streptomycin significantly decreased the content of chlorophyll a at all concentrations. In a concentration-dependent pattern, streptomycin significantly reduced the maximum photochemical efficiency (φP0), variable fluorescence (Fv), potential activity of PSⅡ (Fv/F0), active reaction center per unit area (RC/CS0), the performance index based on absorbed light energy (PIabs) and the quantum energy yield of the light energy absorbed by the reaction center for electron transfer (φE0). However, Streptomycin significantly increased the maximum fluorescence relative to chlorophyll a (Fm/Chl. a), the light energy absorbed by each active reaction center (ABS/RC) and heat dissipation (DI0/RC) in a concentration-dependent pattern. A K-point at chlorophyll a fluorescence transient curve was found when the concentration is greater than 0.1 mg/L. These results suggest that streptomycin might affect the growth of Nostoc by inhibiting the electron transport of photosynthetic system Ⅱ (PSⅡ) and reducing active reaction centers, and that high concentrations of streptomycin showed an inhibitory effect on the growth of algae.
Available online   , doi: 10.7541/2019.061
[Abstract](72) [FullText HTML](36) [PDF 711KB](3)
Abstract:
Atrina pectinata is a commercially important species in the Northern South China Sea. This study analzyed genetic diversity and genetic structure of A. pectinata in Northern South China Sea based on 191 individuals of 7 populations using Cytochrome Oxidase Ⅰ(COⅠ) sequence. A 600bp segment of COⅠ genes were sequenced, from which 113 polymorphic sites were tested and 73 haplotypes were defined. The total population in Northern South China Sea had high haplotype diversity (0.8996) and high nucleotide diversity (0.0257). However, 6 populations in L1 group (ST, YJ, ZJ, HK, QH, BH) had high haplotype diversity (0.8133—0.9286) and low nucleotide diversity (0.0033—0.0045). Based on neighbor-joining tree and haplotype network, 7 populations were classified into two groups, named L1 group and L2 group (FCG), and no clustering corresponding to sampling localities was found in L1 group haplotypes. Fst analysis showed no obvious genetic differentiation among 6 populations in L1 group (Fst= –0.0200— –0.0055, P>0.05) and significant genetic differentiation between L1 group and L2 group (Fst=0.8729—0.8821, P<0.01). Both Tajima’s D (D=–2.3190, P=0) and Fu’s Fs (Fs=–26.7990, P=0) of L1 group yielded significant negative values. Unimodal distribution was observed in L1 group. However, in L2 group, Tajima’s D (D=–1.4320, P=0.0565) was insignificant negative value, and Fu’s Fs (Fs=4.9540, P=0.9620) was insignificant positive value. These data implied L1 group and L2 group might have differentiated into two populations. The frequent gene exchange resulted in high genetic homogeneity among 6 populations in L1 group.
Available online   , doi: 10.7541/2019.078
[Abstract](177) [FullText HTML](69) [PDF 702KB](27)
Abstract:
This study explored effects of 3 light-paths (LP) of column and flat plat photobioreactors under two kinds of nitrogen concentrations on the growth, total lipid and AA content of Parietochloris incisa using BG-11 medium. The results showed that cell growth rate increased by the smaller light-path of two kinds of photobioreactors. The maximal biomass were 5.09 g/L in column photobioreactor (2.5 cm LP) and 2.98 g/L (3.0 cm LP) in flat plate photobioreactor with nitrogen concentration at 17.6 mmol/L. The highest total lipid and AA content at the biggest length of light-path under 1.0 mmol/L nitrogen concentration were 39.23% and 13.21% in column photobioreactor (6.0 cm LP) and there were 40.74% and 11.33% in flat plate photobioreactor (5.0 cm LP). In addition, the maximal volumetric productivity of total lipid was 216.39 mg/(L·d) in column photobioreactor (2.5 cm LP) under 17.6 mmol/L nitrogen concentration and it was 135.93 mg/(L·d) in flat plate photobioreactor (1.5 cm LP) under 1.0 mmol/L nitrogen concentration. The AA volumetric productivity reached the maximum level in the biggest light-path of column [21.65 mg/(L·d)] and flat plate photobiorector [19.42 mg/(L·d)] under 1.0 mmol/L nitrogen concentration. These results indicate that the 6.0 cm light-path column photobioreactor or 5.0 cm light-path of flat plate photobioreactor under 1.0 mmol/L nitrogen concentration are the best condition to culture Parietochloris incisa for AA production.
Available online   , doi: 10.7541/2019.072
[Abstract](120) [FullText HTML](52) [PDF 1149KB](20)
Abstract:
The morphology of four widely distributed ciliates (Stylonychia mytilus, Tetmemena pustulata, Paramecium caudatum, Coleps hirtus) from Songhua River were studied using living observation and silver staining methods to complementally descript the living and ciliary pattern characters of Harbin populations of these four species including the arrangement of six rows of dorsal kineties after protargol impregnation and the specific statistics of the numbers of left and right marginal rows of S. mytilus. The results showed that the morphological features of Harbin population S. mytilus were basically consistent with previous reports, except that small membranes of Harbin population were more than previous populations. Compared with the Mohe population, the Harbin population T. pustulata were similar in morphology, infraciliature and the occurrence pattern, and had slightly higher in the number of left and right marginal and more micronuleus. Compared with the Qingdao populations of P. caudatum, Harbin population had significantly less collecting canals. Compared with previous populations, Harbin population of C. hirtus had slightly larger body size.
Available online   , doi: 10.7541/2019.073
[Abstract](179) [FullText HTML](42) [PDF 566KB](11)
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Ichthyoplankton were collected in the upper mainstem of the Yangtze River at Yibin, Zhuyang and Mudong in 2009, 2012 and 2015 to determine the occurrence dynamic and abundance of Pseudolaubuca engraulis (Nichols) larvae. The abundance of P. engraulis larval peaked from mid-May in 2009 and 2012 (pre-impoundment of dam cascade in the Jinsha River), while few larvae occurred before late-June and the abundance peaked from mid-July in 2015 (post-impoundment of the dam cascade). Hypolimnetic and clean water discharge from the dam cascade are critical factors on delaying spawning seasons and peak occurrence of the larval fish. The abundance of P. engraulis larvae showed an apparent increase at Yibin and a slight increase at Zhuyang in 2015 comparing to that in 2012 and 2013, indicating that the fish may adapt to the altered habitat environments by the dam cascade. Abundance of P. engraulis larvae at Mudong showed a significant increase during 2009 to 2015. The increase of the fish is probably related to the increasing operational water level (from 156 m to 175 m) of the Three Gorges Reservoir (TGR), which created slow flow habitats at Mudong section and then offered a favorable nursery for the larvae. Based on the results of this study, it is suggested that the temporal-spatial variation of P. engraulis larvae was jointly controlled by the upstream dam cascade and downstream TGR. Meanwhile, we suggest that the " River-Reservoir” ecosystem, constrained by the tail of reservoir (even all the reservoir) and its upstream river section, may have similar functions as the river-floodplain ecosystem in natural systems, and is valuable to the successful recruitment of fishes which produce drifting-egg.
Available online   , doi: 10.7541/2019.066
[Abstract](80) [FullText HTML](39) [PDF 763KB](6)
Abstract:
Heavy metal copper (Cu) and cadmium (Cd) are common contaminants in water environment and dangerous to the existence and edible safety of fish. In this study, laboratory simulated semi-static method was used to feed Carassius auratus by simultaneously adding Cu and Cd to the water. The concentrations of Cu and Cd were detected in different places of Carassius auratus. Moreover, the effect of Cu and Cd on different tissues of Carassius auratus was evaluated by histopathology. The results showed that liver, gill, gut and muscle of Carassius auratus had enrichment of Cu and Cd. The Cu concentration was significantly higher than Cd in Carassius auratus. With increasing Cd concentration in water, Cd concentration in the tissues of Carassius auratus gradually increased. However, Cu concentration in Carassius auratus showed a declined trend. After fed 14 days with Cu and Cd concentrations of 0.15 and 0.20 mg/L, respectively, the muscle of Carassius auratus had a Cd concentration of 0.13 mg/kg, which exceeded the limit value of 0.10 mg/kg in Chinese industrial standard on " the limit of poisonous and harmful material in aquatic products”. After combined treatment of both Cu and Cd, the tissues of Carassius auratus showed various pathological changes. Moreover, the damage degree increased with increasing concentrations of Cu and Cd. Liver tissue showed hemagglutination, lipoidosis and cell vacuolation. Gill tissue manifested hyperplasia, edema and mucosal swollen. Gut tissue included goblet cell swollen, columnar cell hyperplasia, lamina propria vacuolation, mucosal erosion and villi exfoliation. Muscle tissue showed myofiber fracture, aggregation, collapse and dissolution, as well as broad gap of myofiber. Cu and Cd accumulated in Carassius auratus, and histopathological damage was present in the tissues. Moreover, the higher concentration, the more obvious damages, and these were mainly due to the accumulation of Cd in the body. This study can provide data support for the growth condition and edible safety of heavy metal pollution on Carassius auratus.
Available online   , doi: 10.7541/2019.063
[Abstract](71) [FullText HTML](34) [PDF 856KB](4)
Abstract:
To investigate effects of high energy diets on serum biochemical indices of grass carp (Ctenopharyngodon idella), grass carp [N= 320, average initial body weight=(55.0±2.5) g] were randomly assigned into 4 groups with 4 replicates for each group (N=20 fish/replicate) to fed three times daily to satiation with the control diet (CON) and three high energy diets for 11 weeks. The 3 high energy diets were 11% increased protein, 11% increased fat or 11% increased Carbohydrate compared to the control diet, respectively. The fish were fasted for 48h and then refed a single meal for 0, 2, 8, or 24 hours before collection for analyzing eight serum biochemical indices. Statistical analysis using two-way ANOVA showed that seven serum biochemical indices except total cholesterol (TCHO) were significantly affected by refeeding time, and all 8 biochemical indices were significantly affected by the different diets. Peak values of glucose (GLU) contents and aspartate transaminase (AST) activities presented at 2h after refeeding, and peak values of alanine transaminase (ALT), alkaline phosphatase (ALP) activities and low density lipoprotein-cholesterol (LDLC) contents appeared at 24h after refeeding. The peak value of triacylglycerol (TAG) content occurred at 8h after refeeding, but there was no obvious peak value for serum TCHO or high density lipoprotein-cholesterol (HDLC) contents. At 24h after refeeding, compared with the CON diet, the higher energy diets had higher GLU contents and ALT activities but with similar activities of AST and ALP, and the contents of TAG, TCHO and HDLC. Our results demonstrated that both refeeding time and high energy diets regulated the serum biochemical indices, indicating that it is necessary to make sampling time synchronize in different groups for the accuracy of serum biochemical indices.
Available online   , doi: 10.7541/2019.065
[Abstract](85) [FullText HTML](44) [PDF 881KB](5)
Abstract:
In this study, we utilized high-throughput sequencing technology to explore thechanges of intestinal microbiota of Hirudo nipponia among fasting group, refeeding groups and control group. The results showed that (1) on the hierarchical level of the phylum, the microflora mainly include Proteobacteria, Bacteroidetes and Firmicutes; (2) on the hierarchical level of genera, the dominate microflora include Aeromonas, Mucinivorans, Bacteroides and Erysipelothrix. The results also indicated that fasting and refeeding diversity and abundance of the dominate microflora, including Aeromonas and Mucinivorans. This study lays the foundation for more detailed composition and function of digestive tract microflora in H. nipponia.
Available online   , doi: 10.7541/2019.068
[Abstract](168) [FullText HTML](86) [PDF 1286KB](20)
Abstract:
This study described pathological features of a spontaneous spermatocytic seminoma in gibel carp Carassius gibelio. Histologically, the neoplasm founded in the abdomen was encapsulated invasive spermatocytic seminoma with an inconspicuous lobular architecture and diffuse fibro-connective septa with lymphocytic infiltration. For its ultrastructure, undifferentiated spermatocytes and fewer supporting cells were the unique features of the neoplasm. Compared with the histological features of normal testis of gibel carp, this neoplasm was identified as a spermatocytic seminoma. The first report of spermatocytic seminoma with lymphocytic infiltration in fish may contribute to the establishment of fish model of spermatocytic seminoma.
Available online   , doi: 10.7541/2019.069
[Abstract](78) [FullText HTML](34) [PDF 886KB](4)
Abstract:
The epizootic outbreaks were recorded in Chinese soft-shelled turtle farm in Hangzhou, Zhejiang province in summer of 2016. The diseased turtles were an orexia, lags in responsive, abnormal or lonely swimming. The moribund turtles would creep and lie on the shore with continuous head-shaking with a 20% mortality. Gram positive rod with single endospore were isolated from liver, kidney, spleen and blood of moribund turtles with typical symptoms. Stain T91-1 was identified as Bacillus cereus with API 50 CHB strip, 97.4% similarity to B. cereus reference strains by BioMérieux APIWEB Plus software V3.2.2. The identification was confirmed by phylogenetic analysis using 16S rDNA and gyrB whole gene, 99% similarity to type strains ATCC14579 of B. cereus T91-1 that showed typical β-hemolytisis on sheep blood agar and large transparent circle on the milk agar, indicating the existence of hemolytic and extracellular protease toxin. The T91-1 challenged turtles died from day 3 to day 7 with the symptoms similar to natural infected turtles, and LD50 of B. cereus T91-1 was 4.91×105 CFU/ind. Large number of Bacillus-like rods were observed in blood and liver smear stained with Wright-Giemsa. A large number of Bacillus-like were found in kidney, liver, lung and heart of native diseased turtles with vascular dilatation and congestion, as well as infiltrated eosinophils. All ICR suckling mice were killed at day 3 after oral administrated with T91-1 at concentration ranged from 1.2×106 CFU/mL to 1.2×108 CFU/mL with hemorrhagic subcutis and cerebrum. Four weeks old mice were injected or oral administrated with T91-1 at 1×107—109 CFU/mL, which showed anorexia, lags in responsive within 12h to 24h, but no death was recorded. These results demonstrated that B. cereus T91-1, with the strong pathogenicity to Chinese soft-shelled turtles and enterotoxigenic to mice, could be the pathogen of outbreaks of Chinese soft-shelled turtles diseases in this farm in Hangzhou.
Available online   , doi: 10.7541/2019.081
[Abstract](83) [FullText HTML](18) [PDF 537KB](11)
Abstract:
Farmed fish has become the main source to meet the demand of human for aquatic products. Cobia Rachycentron canadum is one of the main farmed marine fish in southern China, which were cultured in sea net due to its fast growth, tender meat and high nutritional value. However, the cobia cultivation mainly depends on iced fresh fish, especially for the culture of large-size fish, which seriously restricts the development of farming industry. It is urgent to develop the corresponding formula for fish growth at different stages. This article summarized the research progress of cobia on nutrients requirements such as protein, fat, amino acids, fatty acids and micronutrients, the alternative of fish meal and fish oil in feed, the application of feed additives, as well as the developmental status of feed industry to provide reference for studies on nutritional requirements and the development of compound feeds of cobia.
Available online   , doi: 10.7541/2019.076
[Abstract](58) [FullText HTML](18) [PDF 1086KB](7)
Abstract:
To systematically understand the community structure of macrozoobethos in the mid-lower Yangtze mainstem, two field investigations were conducted on 13 sections along Yichang-Anqing reaches in May-June and October-December 2016, respectively. A total of 96 taxa of macrozoobenthos were recorded with the most abundant group of aquatic insects that account for 49.0% of the total. The frequency of occurrence was relatively low (<1%) for most species (58.7%), and species composition were obviously different among reaches. The density of macrozoobenthos was (213±58) ind./m2, and the biomass was (0.202±0.066) g/m2. Community structure was different between pre-flood and post-flood periods, where obvious decreases in both species number and standing crops were found in the latter. Compared with the pre-damming data, community structure of macrozoobenthos had increased species number and decreased standing crops. Environmental analyses showed that velocity was the key factor affecting the distribution of macrozoobenthos, while substrate and water quality parameters were of little importance. The sharp decline in standing crops of macrozoobenthos was closely related to the increased scouring effects in post-damming period. These results suggest to carry out regulation of flow and sediment, to create slow-flow habitats and to strengthen protection of sand bars with regard to macrozoobenthos conservation in the Yangtze mainstem.
Available online   , doi: 10.7541/2019.075
[Abstract](81) [FullText HTML](33) [PDF 692KB](6)
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The Xijiang Oxbow located in the Anqing section of Yangtze River is the only ex-situ conservation area for the Yangtze finless porpoise (Neophocaena asiaeorientalis). In order to understand the plant community structure in riparian zone of the Xijiang Oxbow and the habitat of the Yangtze finless porpoise in this area, the vegetation in 10 transects of the Xijiang Oxbow was investigated in the summer, 2017. This study identified 166 species of vascular plants with 50 families and 131 genera including 1 family with 1 genus and 1 species of algae, and, 1 family with 1 genus and 2 species of ferns, as well as 163 species of 129 genus belonging to 48 families of seed plants. The main families were the Papilionaceae, Compositae and Gramineae, and the distribution types of families and genera were relatively rich. Besides, plant community structure showed that Shannon-Wiener indexes were between 0.213—0.899 with a mean of 0.629±0.399, and Simpson indexes were between 0.135—0.465 with a mean of 0.315±0.204. The richness of species ranged from 3 to 14 with the same trend as the diversity indexes. The vegetation distribution in riparian zone of the Xijiang Oxbow presents a significant spatial feature. The areas destroyed by human activities on both sides of the river have lower diversity compared to the natural area covered by plant that has higher community diversity and richness. In general, the riparian zone of the Xijiang Oxbow has rich vegetation and high coverage to improve water quality and provide a good spawning and feeding ground for small settled fish, which own great significance to maintain the habitat and breeding for the migratory population of the Yangtze finless porpoise.
Available online   , doi: 10.7541/2019.074
[Abstract](74) [FullText HTML](42) [PDF 3271KB](6)
Abstract:
The coastal waters of Zhejiang Province that contain lots of islands and the water exchange fully in this area were affected by the Yangtze River diluted water, Taiwan warm current, coastal water of Jiangsu Province and the Yellow Sea cold water mass. It was the spawning and feeding grounds of multitudinous crabs because of abundant nutrient salts and food organisms. The crab resources and distribution and community ecology in the East China Sea have been reported since 1990s but mostly concentrated in the sea that was out of the 30 m's isobath and reported before 2008. Thus, these studies cannot represent the characteristics of crab community in the whole coastal waters of Zhejiang Province due to the small research areas relatively. The current study analyzed the content of coastal crab community including species composition, floristic feature, dominant species, distribution of the resource density, species diversity and the relationship between the community structure and the environmental factors based on the fishery resources in Zhejiang coastal area in 2015 designated survey data using ecosystem diversity indexes, abundance/biomass comparison curve (ABC curve) and canonical correspondence analysis (CCA). The 28 captured crab species were belong to 11 families and 19 genera that were dominated by warm water species with a 78.57%. The dominant species were Charybdis bimaculata, Portunus trituberculatus and Charybdis japonica in spring and Portunus trituberculatus and Charybdis bimaculata in summer. The average resource density was 244.38 and 585.60 kg/km2 in spring and summer respectively, and the density of middle-north Zhejiang coast area was higher than that of the south part. The average values of species abundance index (D), species diversity index (H′) and species evenness index (J′) were not related, indicating a low crab community diversity. According to the abundance/biomass comparison curve (ABC curve), crab community in spring and summer was seriously and moderately disturbed respectively. The result of Canonical Correspondence Analysis (CCA) analysis showed that the depth of water was the primary environmental factor regulating the distribution of crab community in all 9 environmental factors, and the salinity was the secondary environmental factor. These results enrich the basic information of crab species diversity in China's coastal waters, which hold a useful scientific significance for understanding the dynamic changes of crab diversity in Zhejiang even the East China Sea. At the same time, it can provide reference for the establishment of marine ecological and environmental protection measures in offshore of Zhejiang Province.
Available online   , doi: 10.7541/2019.070
[Abstract](177) [FullText HTML](87) [PDF 1348KB](23)
Abstract:
The morphology and annulus characteristics of Ptychobarbus dipogon were described by eight aging materials in Tibet Autonomous Region, China, and then the suitable aging materials were determined in term of structures and annuli characteristics of eight aging materials. Hip scale was seriously specialized, annulus characteristics of chest scale, lateral-line scale, back scale were not obvious. Compared with the lapillus, the average percentage error was 41.63% for hip scale, 51.26% for chest scale, 50.50% for lateral-line scale, and 51.26% for back scale. The average percentage errors of asteriscus (12.28%), vertebrae (15.67%), and opercular bones (17.81%) were little different from lapillus. Below 23 years old fish, the average age of lapillus was 14.39 years that was similar with asteriscus (13.13 years) and vertebrae (13.20 years), but it was significantly higher than opercular bones and four scales (P<0.05). Above 23 years old fish, the average ages of seven aging materials were significantly lower than that of lapillus (P<0.05). The maximal age was 49 years for lapillus, 35 years for asteriscus, 34 years for vertebrae, 34 years for opercular bones, 22 years for hip scale, 19 years for chest scale, 16 years lateral-line for scale, and 17 years for back scale. The relationship between the age of lapillus and body length was logarithm function (P<0.01). Therefore, the lapillus was the suitable age determination material for Ptychobarbus dipogon.
Available online   , doi: 10.7541/2019.071
[Abstract](143) [FullText HTML](63) [PDF 551KB](3)
Abstract:
Carbon and nitrogen stable isotopes of herbarium specimens have been used by ecologists to study long-history pollution and climate change. However, whether the preparation and preservation procedure impact isotopic signatures of herbarium specimens remain unclear. We tested the effect of herbarium on three submerged macrophyte species, and found the variations by both preparation and preservation processes. The press procedure significantly reduced carbon stable isotopes of submerged macrophytes for P. malaianus by 1.78‰, M. spicatum by 0.98‰ and C. demersum by 0.72‰. The press procedure reduced C. demersum nitrogen stable isotopes by 1.1‰. The soak procedure did not affect nitrogen stable isotopes of submerged macrophytes, but increased carbon stable isotopes of M. spicatum and P. malaianus by 1.00‰ and 0.52‰, separately. Carbon stable isotopes of C. demersum increased less than 0.08‰. Preparing procedures had larger effect on carbon isotope than nitrogen isotope. These influences were highly variable between species and times. The results suggest that if the interested stable isotopic variations are within 3‰, herbarium specimens are not suitable samples for the relevant studies without the experimental corrections.
Available online   , doi: 10.7541/2019.058
[Abstract](38) [FullText HTML](20) [PDF 569KB](4)
Abstract:
In order to elucidate the mechanisms of sex determination and differentiation in Culter alburnus and to control breeding, this study analyzed the role of C. alburnus Sox9 during gonad development. The cDNA sequence of two homologous genes Sox9a and Sox9b were obtained. The full-length cDNA of Sox9a was 1642 bp, encoding 458 amino acids; the full-length cDNA of Sox9b was 1673 bp, encoding 456 amino acids. Sequence analysis revealed that the similarity between them was 73.95% and the HMG motif regions were highly conservative. Protein second structural prediction showed that Sox9a and Sox9b contained a HMG domain and two nuclear localization signal (NLS) sequences; their three-dimensional structure contained multiple spiral structures. Phylogenetic tree analysis discovered that C. alburnus Sox9a was the closest to Oreochromis niloticus, while Sox9b formed a separate branch. Sox9a was highly expressed in brain and testes, followed by muscle, fins, eyes and ovaries, and rarely detected in kidney, spleen and liver. The expression of Sox9b were only detected in brain, fins, eyes and testes. Promoter CpG methylation analysis of Sox9a showed that CpGs were not methylated in the testes, whereas CpGs were hypermethylated in the ovaries. These results suggested that promoter CpG methylation can regulate sexual dimorphic expression of sex-related genes, and epigenetic modification may play an important role in the gonad development of C. alburnus.
Available online   , doi: 10.7541/2019.064
[Abstract](136) [FullText HTML](75) [PDF 594KB](10)
Abstract:
The black rockfish (Sebastes schlegelii) has been an important economic marine fish species of deepwater cage farming, enhancement releasing and fishing in the northern coast of China. Its reproduction is ovoviviparous, during which the embryo is produced in female fish and usually grow to free fish around May. There is no report on the nutritional requirements and metabolic characteristics of the early development of S. schlegelii. In order to investigate the compositions of amino acids and fatty acids as well as their changes for S. schlegelii in different developmental stages, related analysis at different stages including fertilized eggs (FE), embryo stage (ES), primiparous larvae (PL1), pre-larva (PL2), post-larva (PL3) and juvenile (J) were conducted by biochemical analysis methods. The S. schlegelii was sampled at the breeding demonstration base of Shandong Marine Resource and Environment Research Institute, Yantai, Shandong Province from April to July in 2016. The results showed that the total amino acid content decreased significantly from FE to PL1, and then increased significantly during prophase PL3, and finally had another significant decrease in the late stage of J (P<0.05). The total amount of free amino acid during FE was the lowest among the six stages (12.77 mg/g), which then significantly increased from FE to PL1 (P<0.05), and reached to the highest level of 92.19 mg/g, and after that it diminished first, then rose, and decreased again (P<0.05). The content of free essential amino acids was significantly higher than that of free nonessential amino acids at each developmental stage. The percentage of free amino acids at each stage was 2.37%—19.66%. Twenty-nine fatty acids were detected in S. schlegelii, including 9 saturated fatty acids (SFA), 10 single unsaturated fatty acids (MUFA) and 11 poly unsaturated fatty acids (PUFA). The major fatty acids in fertilized eggs were C22:6n-3 (DHA), C18:ln-9c, C16:0 and C20:5n-3. At the embryonic period, the order of utilization rate of fatty acid was SFA, MUFA, n-6PUFA and n-3PUFA. Meanwhile, C18:3n-3, C18:0, C16:1n-7 and C20:5n-3 were main sources of energy metabolism. n-3PUFA was preserved at priority, and especially the actual utilization ratio of C22: 6n-3 (DHA) is the lowest (9.71%) and the highest practical utilization amount was C16:0 (10.94 mg/g). The order of utilization rate of fatty acid at the endogenous feeding stage was MUFA, n-6PUFA, SFA and n-3PUFA. C16:1n-7, C18:0, C20:4n-6(ARA) and C18:1n-9c were main sources of energy metabolism, and the highest practical utilization amount was DHA (18.23 mg/g). Compared to EPA and ARA, DHA was preferentially utilized from primiparous larvae to post-larva. While ARA was preferentially utilized during post-larva and juvenile other than EPA and DHA. Therefore, the change trends were completely different between total amino acid and free amino acid content in vivo developmental stages. The practical utilized amount and utilization ratio were different in embryo stage and endogenous feeding stage. Polyunsaturated fatty acid DHA was preferentially utilized in larval stage, while ARA was preferentially utilized in juvenile. It was recommended to enhance biological bait enriched with DHA in larval breeding of S. schlegelii and add ARA on pellet feed in juvenile. This method can prevent fingerlings of nutrition inadequacy and guarantee survival rate.
Available online   , doi: 10.7541/2019.060
[Abstract](36) [FullText HTML](15) [PDF 686KB](2)
Abstract:
Siderophore is considered as one of the virulence factors of Aeromonas hydrophila and is encoded by seven genes of amoCEBFAGH. AmoCGH have been confirmed to be involved in the synthesis of siderophore in previous studies. RT-PCR assay indicated that the expression of amoAEF genes were regulated by iron. In order to further explore the function of genes amoAEF, in this study, we used the suicide plasmid PRE112 to construct gene deletion mutant strains ΔamoA, ΔamoE and ΔamoF based on the infusion PCR and gene homologous recombination principle. The detection of the siderophore synthesis in the wild strains and mutant strains were performed using CAS plate test and arnow test. The results showed that Aeromonas hydrophila ΔamoA, ΔamoE and ΔamoF were successfully constructed. The growth of wild strain, ΔamoA, ΔamoE and ΔamoF had no significant difference in iron-riched medium, while in iron-depleted medium, the growth and siderophore synthesis capacity of ΔamoA, ΔamoE and ΔamoF were significantly lower than that of the wild strain. The results suggested that amoA, amoE and amoF are the critical synthesis genes of siderophore, and the growth of the deletion mutants were inhibited under low iron conditions.
Available online   , doi: 10.7541/2019.057
[Abstract](265) [FullText HTML](72) [PDF 721KB](9)
Abstract:
The Fused in sarcoma gene (FUS) is a RNA-binding protein implicated in the regulation of transcription and pre-mRNA splicing. Mutations in FUS lead to neurodegenerative diseases including ALS (amyotrophic lateral sclerosis) in mammals. However, little is known about fus function in fish species. Here, we generated frame-shift alleles in the zebrafish fus gene using CRISPR/Cas9 mutagenesis. Homozygous fus-/- zebrafish developed normally and were fully fertile, except that their body size and body weight were smaller than that of wild-type zebrafish at both the larvae and adult stages. In addition, the female-biased sexual size dimorphism in adult zebrafish was also eliminated when fus was mutated. The expression levels of several growth-related genes including gh1, ghra, igf1, igf2a, stat5.1 and socs6 were significantly reduced in fus-/- zebrafish larvae compared with the wild-type. However, there was no effect on locomotor activity in fus-/- zebrafish. Therefore, different from its functions in mammals, fus is not associated with motoneuron development and has a divergent function in regulating somatic growth and sexual size dimorphism in fish species.
Available online   , doi: 10.7541/2019.067
[Abstract](60) [FullText HTML](41) [PDF 949KB](5)
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Cadmium (Cd) and mercury (Hg) are the most common pollutants found in water environment to cause tissue damages and induce apoptosis in invertebrates. To investigate the toxicological effects of Cd and Hg on the ovary of Eriocheir sinensis, the crabs were exposed to different concentrations of Cd2+ (0, 0.63, 1.26, 2.52, 5.04 and 10.07 mg/L) or Hg2+ (0, 0.06, 0.11, 0.23, 0.46 and 0.91 mg/L) for 6 days. The accumulation of Cd2+ and Hg2+ in the ovary increased significantly with the increased concentrations. The extent of oxidative stress caused by Cd2+ or Hg2+ was investigated by determining the oxidative stress indexes in the crab ovary. MDA, H2O2 and NO contents, MT (Metallothionein) mRNA levels and NOS activity in the ovary increased with the increased concentrations of Cd2+ and Hg2+. SOD, CAT and GPx activities initially increased, and then decreased with the increased Cd2+ or Hg2+. The result suggest that Cd2+ and Hg2+ can cause excessive accumulation of free radicals in ovary which lead to lipid peroxidation, and that MT induction in the ovary is a protective response against oxidative damage via detoxification of the ovary of E. sinensis. The induced antioxidant enzymes by Cd2+ and Hg2+ could effectively eliminate reactive oxygen species (ROS) from the tissues and maintain a redox-balance system to provide protection against Cd2+ and Hg2+-induced oxidative stress.
Available online   , doi: 10.7541/2019.080
[Abstract](214) [FullText HTML](116) [PDF 676KB](13)
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To optimize the cultivation condition of microalgae, single-factor design and orthogonal experiments were performed to assess the growth rate, total lipid content and fatty acid composition of STR01 by temperature, light intensity and salinity. The results showed that all these ecological factors exerted significant effects on the growth, total lipid content and fatty acid composition of STR01 (P< 0.05) with the appropriate temperature for growth at 15—35℃, the optimum temperature at 25—30℃ (K-value 0.679—0.682) and the optimum temperature for total lipid content accumulation at 25℃ (17.23%). The highest PUFA content at 34.23% appeared at 20℃. The appropriate light intensity for growth was 40—120 μmol/(m2·s) and the optimum one was 60 μmol/(m2·s). The light intensity of 40 μmol/(m2·s) had the highest PUFA accumulation at 34.29%. The appropriate salinity for growth was 10—35 and the optimum salinity was 25. The orthogonal experiments showed that the optimum condition for growth was temperature 30℃, light intensity 60 μmol/(m2·s), and salinity 25, and that the optimum total lipid accumulation was temperature 30℃, light intensity 60 μmol/(m2·s) and salinity 20, and that the optimum PUFA content was temperature 25℃, light intensity 60 μmol/(m2·s), and salinity 20 at 37%. In conclusion, STR01 was promising prospect in future aquaculture with fast growth rate and high total lipid and PUFA contents.
Available online   , doi: 10.7541/2019.077
[Abstract](219) [FullText HTML](135) [PDF 779KB](29)
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To understand the structure and its driving factors of macroinvertebrate community, two surveys were conducted in the Anning River and its tributaries in wet season (July and August 2016) and dry season (January and February 2016). Furthermore, sampling was also performed monthly from July 2015 to June 2016 in the tributaries of the Anning River. As a result, a total of 122 species of macroinvertebrates were collected, which belonged to 115 genera of 5 phyla. Among them, aquatic insects (109 species) were dominant taxa. The densities and biomass of macroinvertebrate community were much higher in the tributaries than those in the mainstream both in the wet and dry seasons, and were much higher in the dry season than those in the wet season both in the mainstream and tributaries. All through the year, the dominant species in the tributaries were Baetis sp., Simulium sp., Epeorus sp., Baetiella sp., Peltoperlidae spp. and Ephemerella sp. Temporal variability of macroinvertebrates showed that the highest density was in December and the lowest one in July; while the highest biomass was in January and the lowest one in July. Canonical correspondences analysis (CCA) indicated that substrate type and altitude were the key factors driving the macroinvertebrate distribution in the wet season, whereas flow velocity, altitude and water temperature were the significant driving factors in the dry season. In addition, monthly variations of macroinvertebrate structure in the tributaries were relative to the ecological factors such as water temperature and conductivity. Overall, this study provides a scientific basis for the studies and conservation of biodiversity in high altitude areas.
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[Abstract](95) [FullText HTML](61) [PDF 735KB](19)
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.
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[Abstract](165) [FullText HTML](89) [PDF 686KB](23)
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.
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[Abstract](293) [FullText HTML](153) [PDF 601KB](10)
Abstract:
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](444) [FullText HTML](239) [PDF 679KB](53)
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.
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[Abstract](375) [FullText HTML](220) [PDF 994KB](48)
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.
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[Abstract](134) [FullText HTML](87) [PDF 426KB](17)
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.

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2019, 43(2): 233 -242   doi: 10.7541/2019.029
[Abstract](450) [FullText HTML](211) [PDF 599KB](48)
Abstract:
The purpose of this study was to investigate dietary lipid requirement and the effect of different lipid levels on the body composition and plasma biochemical indices in cobia (Rachycentron canadum L.) at two different body sizes (initial weight: 40 g vs. 500 g). Six isonitrogenous diets were formulated using fish meal, soybean meal and wheat meal as the protein source and fish oil as lipid source, with six different lipid contents of 5.27%, 8.22%, 10.81%, 14.26%, 17.32% and 20.94% (at a dry matter basis), respectively. Fish at two different growth stages were randomly distributed to seawater floating net cages (1.5 m×1.5 m×2.5 m) at a density of 25 and 10 fish per net cage, respectively. Each diet was fed to triplicate groups of fish twice daily to satiation for 10 weeks (40 g) and 8 weeks (500 g), respectively. Specific growth rate (SGR) and feed efficiency ratio (FER) significantly increased and then decreased with increasing dietary lipid levels at both developmental stages. The Viscerosomatic index (VSI) and Condition factor (CF) increased significantly with the increase of dietary lipid levels. Significantly higher Hepatosomatic index (HSI), whole-body, liver and muscle lipid contents and lower moisture and protein contents were observed in fish feed the diets containing higher lipid among small fish groups, but no significant difference was detected among large body size groups among above parameters. In addition, the contents of TC, TG, HDL-C, LDL-C and Glu increased significantly with the increasing lipid levels among small fish groups, there was no significant effect among large fish groups in these indices except TG. The overall results showed that based on SGR and FER, the diet containing 13.97%—14.16% and 13.18%—13.47% lipid was most suitable for the cobia culture at the body size of 40 g and 500 g, respectively.
2019, 43(2): 243 -251   doi: 10.7541/2019.030
[Abstract](187) [FullText HTML](64) [PDF 636KB](16)
Abstract:
An 8-week feeding experiment was conducted to evaluate the effects of different monocalcium phosphate (MCP) levels added into high lipid (7.0%) diet on grass carp (Ctenopharyngodon idella) growth performance, lipid metabolism and antioxidant activity. Five levels of MCP (0, 1.0%, 2.0%, 3.0% and 4.0%) were added into high lipid diet, respectively, as basal diets to feed grass carp [initial body weight (47.51±0.52) g]. Each treatment contained three replicates with 15 fishes per replicate. The results showed that the addition of suitable MCP in high-fat diets could significantly increase the weight gain rate (WGR) and the whole-body phosphorus of grass carp, as well as reduce the Feed conversion ratio (FCR) and Viscerosomatic index (VSI). Taking WGR, FCR and whole-body phosphorus as the observational indicators, the analysis of broken-line model showed that the appropriate amount of dietary MCP was 3.26%, 2.96% and 2.63%, respectively. With the increase of MCP in the diet, the whole-body, viscera, muscle, and liver crude lipid content decreased first and then rose, but the whole-body and muscle crude protein had opposite trends. In the MCP3.0% group, grass carp intestinal amylase, lipase, trypsin, and serum alkaline phosphatase (AKP) had the highest activity, while serum triglyceride, hepatic malondialdehyde and acetyl-CoA carboxylase (ACC) were the lowest. Serum total cholesterol was significantly lower in the supplemented group than in the control group (P<0.05). Liver carnitine acyltransferase (CPT-I) activity increased with the increaseing dietary phosphorus. This study indicates that the optimal supplementation of MCP in grass carp high fat (7%) diets was 2.96%—3.26% (TP 1.43%—1.50%), and the appropriate level of MCP can promote the digestion and utilization of dietary nutrients, as well as reduce hepatic lipid accumulation. At the same time, it also increases protein and antioxidant capacity, and decreases lipid, which help promote growth.
2019, 43(2): 252 -258   doi: 10.7541/2019.031
[Abstract](294) [FullText HTML](154) [PDF 478KB](22)
Abstract:
To investigate the effects of dietary carbohydrate on growth performance, body composition and digestive enzyme activities of juvenile crab, Scylla paramamosain, five isonitrogenous and isolipidic diets with varying carbohydrate contents of 20.34%, 25.59%, 30.17%, 35.30% and 39.95% were fed to juvenile crabs with an average body weight of (38.11±0.55) mg of triplicate groups, respectively, for a 3-week feeding trial. Results showed that the survival rate, weight gain ratio and specific growth rate of the juvenile crabs significantly increased firstly and then decreased under the increased dietary carbohydrate level (P<0.05) with the highest level at 30.17%. With the increasing dietary carbohydrate level, the body crude protein and body ash contents of the crabs were significantly increased firstly and then decreased (P<0.05) with the highest level at 35.30%. Dietary carbohydrate level significantly affected amylase activity (P<0.05) without any significant influence on protease and lipase activities (P>0.05). The amylase activity significantly induced by high carbohydrate level (P<0.05). These results indicate that the diet with 25.59%—35.30% carbohydrate could greatly support growth performance. The regression model analysis showed that the most suitable dietary carbohydrate level reach the highest weight gain ratio is 29.93%.
2019, 43(2): 259 -263   doi: 10.7541/2019.032
[Abstract](431) [FullText HTML](161) [PDF 401KB](13)
Abstract:
Leptin has been reported to play important roles in regulation of glucose homeostasis in mammals. However, the relationship between blood glucose and leptin gene expression in teleosts is largely unknown. In the present study, blood glucose and leptin-A gene expression in liver, intestine and visceral adipose tissue were characterized in Chinese perch (Siniperca chuatsi) after fasting or insulin treatment. In the fasting experiment, Chinese perch were fasted for 10 days, sampling at 0, 4h, 2d, 6d and 10d after fasting. Blood glucose was significantly decreased at 10d after fasting; leptin-A mRNA expression was significantly increased in liver at 6d after fasting, and significantly increased in intestine and visceral adipose tissue at 4h after fasting. In the insulin treatment experiment, Chinese perch were intraperitoneally injected with bovine insulin (80 IU/kg body weight) or 0.7% saline as control, sampling at 12h and 36h post treatment. Blood glucose decreased significantly at 12h after insulin treatment, and leptin-A mRNA expression in intestine increased significantly at 36h after insulin treatment, which suggesting that prolonged fasting and insulin treatment decreased blood glucose, and increased leptin-A gene expression in fat depot organ and digestive organ of fish.
2019, 43(2): 264 -271   doi: 10.7541/2019.033
[Abstract](371) [FullText HTML](171) [PDF 505KB](27)
Abstract:
To guide breeding of Megalobrama terminalis, Megalobrama amblycephala and Erythroculter ilishaeformis, two hybrids Megalobrama amblycephala×Erythroculter ilishaeformis, Megalobrama terminalis×Erythroculter ilishaeformisand their parents were analyzed using sixteen microsatellite markers. The mean value of number of alleles (Na) were 3.56, 3.63, 3.44, 4.00 and 4.31, respectively. The mean value of observed heterozygosity (Ho) were 0.3510, 0.3757, 0.3175, 0.3818, and 0.4079, respectively. The mean value of expected heterozygosity (He) were 0.6182, 0.6290, 0.5921, 0.6490 and 0.6825, respectively. And the average value of polymorphism information content (PIC) were 0.5354, 0.5367, 0.5258, 0.5785, and 0.6067, respectively. The average value of polymorphism information content (PIC) of two hybrid population were higher than their parent Megalobrama amblycephala, Megalobrama terminalis and Erythroculter ilishaeformis, indicating a high genetic diversity. The unweighted pair-group method with arithmetic means (UPGMA) showed that populations of the Megalobrama amblycephalaand Megalobrama terminalisfirst grouped together, and that Megalobrama amblycephala♀×Erythroculter ilishaeformis♂ andMegalobrama terminalis♀×Erythroculter ilishaeformis♂ first grouped together, and then they clustered with the Erythroculter ilishaeformis. In addition, the farthest genetic distance (0.5204) was between Megalobrama amblycephala and Erythroculter ilishaeformis, and the nearest genetic distance (0.0853) was between Megalobrama amblycephalaand Megalobrama terminalis. According to the genetic identity analysis, two hybirds groups showed the maternal effect. The alleles of two hybirds were from their parents based on genetic analysis. Particularly, microsatellite primers TTF3, TTF4, TTF10, and Mam25 identified 5 groups. Our results provide important value in breeding, germplasm resources preservation, and germplasm identification of Megalobrama terminalis×Erythroculter ilishaeformis andMegalobrama amblycephala×Erythroculter ilishaeformis.
2019, 43(2): 272 -281   doi: 10.7541/2019.034
[Abstract](303) [FullText HTML](183) [PDF 1066KB](30)
Abstract:
In order to study the effect of IGF-Ⅰ gene on growth traits of topmouth culter (Culter alburnus Basilewsky), IGF-Ⅰ gene was cloned from the genomic DNA of topmouth culter in this study. The gene spanned 14567 bp and comprised five exons and five introns. The five exons of IGF-Ⅰ were 298, 160, 182, 36, and 1360 bp long, respectively. The hypothetical open reading frame of the IGF-Ⅰ cDNA precursor was 486 bp, encoding a putative protein of 161 amino acids. The precursor peptide included a signal peptide (44 amino acids), a mature peptide (70 amino acids), and an E peptide (47 amino acids). The mature peptide comprised four regions: B, C, A, and D. The A and B domains were conserved with six cysteine residues in these two regions to form three disulfide bonds. The B region contained a conserved IGF-Ⅰ receptor recognition sequence (PheB23-TyrB24-PheB25). Analysis of the E peptide showed that IGF-Ⅰ of the topmouth culter was an Ea-2 type. The IGF-Ⅰ amino acid sequence of the topmouth culter had high sequence identity with IGF-Ⅰ proteins from Cyprinidae fish, ranging from 94 to 100%. Phylogenetic analysis of IGF-Ⅰ amino acid sequences showed that IGF-Ⅰ of the topmouth culter does not cluster with the fish from subfamily Cultrinae. IGF-Ⅰ is expressed in all 10 tested tissues with the highest mRNA level in liver, modest level in spleen, heart, testis, and brain, and low level in kidney, gill, stomach, and ovary. The lengths of the four introns of topmouth culter IGF-Ⅰ were 1170, 9364, 251, and 1746 bp, respectively. The variation in the sequence of the introns among species was greater than that of the exons with the highest variation in the third intron. Six microsatellite loci were found in the introns of IGF-Ⅰ with (GATG)5AATAT (ATAG)11 in intron 1, and (CT)8, (TTA)5, (AC)13, (TG)12, and (ATT)5 in intron 2. Four of 6 microsatellite loci were polymorphic, and the genotypes of the four microsatellite loci had no significant correlation with the growth traits of 120 topmouth culter cultured in the same pond (P>0.05). These results provide molecular basis for studying the expression pattern, function and transcriptional regulation of theIGF-Ⅰ gene.
2019, 43(2): 282 -290   doi: 10.7541/2019.035
[Abstract](170) [FullText HTML](58) [PDF 824KB](35)
Abstract:
Asingle gene fragment and combined nucleotide sequences for two gene fragments of mitochondrial DNA (mtDNA), which were 16S ribosomal RNA (16S rRNA) and cytochrome oxidase c subunit 1 (COⅠ), were analyzed for three populations of Trichiurus lepturus (T. lepturus, designated by A, B, and C). The length of 16S rRNA gene of mtDNA and COⅠ was 1130 and 554 bp, respectively. These two gene fragments were combined together to form a gene fragment with the length of 1684 bp for the purpose of subsequent genetic diversity analysis. The average contents of nucleotides T, C, A, and G were 29.0%, 28.9%, 24.4% and 17.7%, respectively in the mtDNA COⅠgene, while those mean contents were 22.7%, 27.6%, 28.0% and 21.7% respectively in 16S rRNA gene. In this study, 43, 8, and 49 haplotypes were defined in 72 individuals by using single and combined gene fragments, in which haplotypes were shared among the mentioned populations. The diversities of haplotypes varied between 0.9766 and 0.9992, indicating that the abundance of haplotypes was within different populations. The nucleotide differences and the nucleotide diversity in each population were in the ranges of 5.111—9.024 and 0.0045—0.0076, respectively. Genetic distances among the populations varied from 0.0048 to 0.00084. These results indicated that genetic diversity in three populations of T. lepturus was considerable. The construction of phylogenetic trees based on Neighbour-Joining (NJ) method showed that several individuals in the same population were aggregated. The achieved findings also indicated that high frequency of gene transfer among different populations resulted in low genetic differentiation. Population A contained richer genetic background than that of populations B and C. The difference within different populations was higher compared to among various populations. It could be concluded that the three mentioned populations of T. lepturus had low genetic diversity based on single and combined mtDNA genes.
2019, 43(2): 291 -297   doi: 10.7541/2019.036
[Abstract](289) [FullText HTML](166) [PDF 987KB](22)
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This study cloned the full-length cDNA of UHRF1 (PtUHRF1) from the swimming crab Portunus trituberculatus using rapid amplification of cDNA ends (RACE). The length of PtUHRF1 cDNA was 2849 bp, which contained a 2298 bp open reading frame to encode 765 amino acids. Structure analysis revealed that PtUHRF1 contained several conserved domains, including UBL, PHD, TTD, SRA and RING. Homology analysis revealed that PtUHRF1 exhibited high identity with other species. The expression of PtUHRF1 at mRNA level was detected in all tested tissues with the highest level in testes. PtUHRF1 showed stage-specific expression during embryonic and larval development with the highest expression in fertilized egg. There were significant differences in PtUHRF1 expression at different ovary and testis stages. In ovary, its expression reached the highest value at stage II, and then decreased gradually, while in testis, the highest expression was detected at stage I, and then decreased as testis developed. These results indicated that PtUHRF1 is important in regulating embryonic, larval and gonadal development in the swimming crab, and provided useful reference for further studies on the roles of this gene in growth and development of P. trituberculatus and crustaceans.
2019, 43(2): 298 -304   doi: 10.7541/2019.037
[Abstract](301) [FullText HTML](69) [PDF 711KB](14)
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Relish and Dorsal, members of nuclear factor-κB (NF-κB) family protein, play crucial role in immune response in Arthropoda. In this study, the cDNA sequences of Relish and Dorsal were cloned by rapid amplification of cDNA ends (RACE). There are 3254 nucleotides in Pt-Rel with a putative open reading frame (ORF) of 2949 bp that encodes a polypeptide of 983 amino acid residues. The Pt-Dor cDNA was 2348 bp in length including an ORF encoding a polypeptide of 637 amino acid residues．Prediction of protein domains revealed that both Pt-Rel and Pt-Dor contained typical NF-κB family structures RHD (Rel homology domain) and IPT (Immunoglobulin-like fold, Plexins, Transcription factors). Alignment of amino acid sequences for Pt-Rel and Pt-Dor revealed high identities with other arthropodas orthologs. Phylogenetic tree analysis based on amino acid sequences showed that the Pt-Rel and Pt-Dor were distinctly clustered with crustaceans Relish and Dorsal, respectively, but separated from insect orthologs. Pt-Rel and Pt-Dor were expressed in all tested tissues with the highest level in hemocytes. Three different pathogenic microorganism significantly induced both Pt-Rel and Pt-Dor expression in primary cultured crab hemocytes at 2h by Candida lusitaniae infection and 4h by Staphylococcus aureus and Vibrio alginolyticus challenge. These data suggest that Pt-Rel and Pt-Dor might be involved in host defense against to microbial pathogens in Portunus trituberculatus.
2019, 43(2): 305 -314   doi: 10.7541/2019.038
[Abstract](252) [FullText HTML](159) [PDF 830KB](13)
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In order to explore the origin and physiological function of ascorbate peroxidase (APX) gene of Hydra sinensis, a full-length cDNA of APX gene of H. sinensis was isolated by rapid amplification of cDNA ends (RACE) technique. The full-length cDNA of APX gene was 1357 bp, containing 107 bp 5′UTR (Untranslated region), 146 bp 3′UTR and a 1104 bp open reading frame (ORF) which encodes a polypeptide of 367 amino-acid residues with a molecular weight of 40.79 kD. BLAST (Basic Local Alignmen Search Tool) showed that most of homologous protein sequences of APX in H.sinensis belonged to the plant kingdom. Phylogenetic results by Maximum Likelihood (ML) method and Bayesian analyses revealed that homologous sequences of APX from plant and animal kingdom each formed a single cluster. The ORF of APX gene was subcloned into plasmid pET-GST and transferred into Escherichia coli BL21 (DE3). The recombinant GST-APX fusion protein mainly expressed in the form of soluble were immunized New Zealand rabbits get the polyclonal antibody against APX for Western blotting assay (WB). H. sinensis was cultured (0, 4, 8, 12, 16, 20 and 24 hours per day with illumination intensity 2000 lx) for 30 days, which up-regulated APX expression under longer illumination time (more than 16 hours per day). Due to continuous photosynthetic activity, a large number of reactive oxygen species (ROS) accumulating in symbiotic green algae could spread to the host cell (hydra cell), and the upregulation of APX expression in H. sinensis may mediate the removal of intracellular ROS.
2019, 43(2): 315 -321   doi: 10.7541/2019.039
[Abstract](187) [FullText HTML](62) [PDF 461KB](26)
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Pacific oysters (Crassostrea gigas), the most widely cultivated shellfish over the world with advantages of fast growth and strong environmental adaption, are suitable materials for selective breeding due to the characters of high fertility, short reproductive cycle and large genetic variation. Broodstocks from white shell strain of C. gigas that had undergone four-generation family selection and three-generation mass selection were used to establish 29 full-sib families and 12 half-sib families by nested design. Random selected individuals were utilized as parents to generate the control families. Phenotypic traits such as growth and survival rate of different periods in larval stage were analyzed. Results showed that the growth performance and average survival rates of white shell families were significantly higher than those of control group with the augmentation of 3.65% to 14.58% and 1.11% to 19.26% in a family dependent pattern, respectively. The G11, G15 and G35 families represented remarkable superiorities in shell height and survival rates. At the age of 19 days, the increased shell heights of G11, G15 and G35 families were bigger than the average values of white shell families by 11.87%, 17.03%, and 30.32%, respectively, and were greater than the average values of the control by 34.09%, 28.18%, and 49.31%, respectively. Besides, the survival rates of G11, G15 and G35 families at 19d were higher than the average values of both white shell by 38.35%, 33.41%, 51.07%, and control families by 65.00%, 59.11%, and 80.18% (G35), respectively. Results of genetic parameters of larvae shell height and shell length of white shell strain indicated that the variation of heritability was ranged from 0.28 to 0.81 in shell height and from 0.42 to 0.88 in shell length, representing the heritability at medium to high level. The genetic and phenotypic correlations were positive between the two growth traits with the correlation coefficients ranging from 0.35 to 0.81 and from 0.57 to 0.85, respectively. This study provides optimum breeding strategy for white shell strains ofC. gigas to improve performance in growth and survival.
2019, 43(2): 322 -329   doi: 10.7541/2019.040
[Abstract](160) [FullText HTML](66) [PDF 655KB](11)
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Transgenic efficiency in mammal cell lines is usually higher but relatively lower in the fish cell lines. Therefore, establishment of any fish cell lines with high transfection efficiency is needed, ideally in the fish model such as medaka (Oryzias latipes). In the present study, we derive a new cell line from medaka muscle termed as OLM (Oryzias latipes muscle), which was maintained in DMEM/HEPES supplemented with 10% bovine serum at 28℃. Up to now, OLM cells have been subcultured over 88 passages and mainly exhibited a fibroblast-like morphology. By chromosomal analysis, OLM has a modal diploid chromosome number of 48. Moreover, transient transfection efficiency by liposome of OLM cell line is up to 40%, which is much higher than that of the common fish cell lines as tested. In addition, the stable OLMs expressing exogenic non-coding RNA or gene are established. Unexpectedly, the OLM is resistant to the fish virus such as Spring viraemia of carp viruses (SVCV), Grass carp reovirus (GCRV) and Singapore grouper iridovirus (SGIV). Taken together, we have established a stable muscle cell line from model fish medaka as an in vitro model for transgenic application.
2019, 43(2): 330 -339   doi: 10.7541/2019.041
[Abstract](119) [FullText HTML](77) [PDF 801KB](9)
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To investigate whether Aeromonas hydrophila generally mediate liver protein expression, isobaric tags for relative and absolute quantitation (iTRAQ) combined with LC-MS/MS were used to screen liver proteins of black carp Mylopharyngodon piceus after infected with Aeromonas hydrophila (BCK0712) for 24 hours. Differentially expressed proteins were screened through identification and quantification analysis. As a result, a total of 4475 proteins were identified and 188 differentially expressed proteins were quantified upon bacterial infection, including 70 up-regulated and 118 down-regulated proteins. Bioinformatics analysis indicated that these differentially expressed proteins were mainly associated with complement and coagulation cascades, spliceosome, endocytosis, oxidative phosphorylation, carbon metabolism, arginine and proline metabolism, etc. Hispathological characteristics including unclear cell boundary, hemorrhage at different degrees and necrosis were observed on liver of black carp infected with A. hydrophila under microscope after hematoxylin-eosin staining. The potential mechanism of regulated proteins by A. hydrophila infection in liver pathology need further investigation.
2019, 43(2): 340 -347   doi: 10.7541/2019.042
[Abstract](159) [FullText HTML](60) [PDF 693KB](9)
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To investigate the effect of different Cd (0 (control), 50, and 200 μg/L Cd2+) on Yellow catfish (Pelteobagrus fulvidraco), fish were exposed for 8 weeks before analyzing the histological structure, antioxidant status and immune-related gene expression in gills. The results showed that Cd2+ exposure induced significant Cd accumulation and histological changes in gill, such as aneurism, hyperplasia, curling of lamella and cell desquamation. Meanwhile, Cd2+ increased the activity of glutathione-S-transferase (GST), glutathione peroxidase (GPx) and anti-hydroxyl radical (AHR) as well as the content of hydrogen peroxide (H2O2), and it decreased catalase (CAT) activity and glutathione (GSH) content. However, Cd2+ had no significant effect on superoxide dismutase (SOD) activity. In addition, Cd exposure up-regulated tumor necrosis factor-a (tnf-a), major histocompatibility complex (mhc), interleukin-10 (il-10), transforming growth factor-β (tgf-β) and complement factor C3 (c3) expressions, but down-regulated interleukin-1β (il-), interleukin-8 (il-8) and lysozyme (lys) transcription levels. These results showed that Cd exposure resulted in the accumulation of Cd, and induced histological damage, oxidative stress and immune response of gill in yellow catfish.
2019, 43(2): 348 -355   doi: 10.7541/2019.043
[Abstract](117) [FullText HTML](69) [PDF 668KB](6)
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C-type lectins are a type of proteins binding to carbohydrates and important pattern recognition receptors in the innate immune system. The classical C-type lectins recognize sugars in Ca2+-dependent manners. It is highly acknowledged that Ca2+ acts as a second messenger in the cell and participates in a variety of physiological and biochemical process. Heavy metal cadmium can lead to dysregulation of cellular calcium homeostasis and interfere with intracellular Ca2+-related information transmission. The aim of this study was to investigate the effects of cadmium stress on the immune responses of two types of lectins, ShLec21 and ShLec23, in the freshwater crab Sinopotamon henanense. The ShLec21 and ShLec23 cDNA were cloned by RACE method, and bioinformatic analysis was carried out. In addition to their constitutive expression in selected tissues, the stimulated expression of the two C-type lectins in hepatopancreas and hemolymph after the treatment of cadmium followed by Aeromonas hydrophila infection were detected. The results showed that ShLec21 cDNA was 863 bp in length that potentinally encoded 152 amino acid residues and ShLec23 cDNA was 681 bp in length that encoded 164 amino acid residues. ShLec21 and ShLec23 clustered into two branches of invertebrates. Both of ShLec21 and ShLec23 were widely expressed in hemolymph, gill, hepatopancreas, intestine, muscle, ovary and testis with highest level in hepatopancreas. Cadmium stress had no significant effect on the expression of ShLec21 and ShLec23 in hepatopancreas and hemolymph. Bacteria A. hydrophila infection significantly down-regulated the expression of ShLec21 (P<0.05) andShLec23 (P<0.01) in the hepatopancreas, and significantly (P<0.05) reduced the expression ofShLec23 in hemolymph. However, in the course of infection with A. hydrophila after cadmium stress, the expression levels of ShLec21 (P<0.05) andShLec23 (P<0.01) were significantly up-regulated in hepatopancreas and hemolymph. The results suggest that cadmium stress could upregulate the expression ofShLec21 and ShLec23 in response to A. hydrophila infection in a certain extent.
2019, 43(2): 356 -361   doi: 10.7541/2019.044
[Abstract](262) [FullText HTML](183) [PDF 945KB](17)
Abstract:
To assess the effects of PFOS pollution on burst swimming performance and metabolic recovery of fish, juvenile Spinibarbus sinensis were exposed to different PFOS concentrations (0, 0.32, 0.8, 2 and 5 mg/L) for 28d. There after, the burst swimming speed (Uburst), relative Uburst (rUburst), resting metabolic rate (RMR) and metabolic recovery after exhaustive swimming of the fish were measured. The results showed that PFOS had a profound effect on the Uburst and rUburst of fish (P<0.05). TheUburst and rUburst were reduced by 17.4% and 10.8%, respectively, upon exposure to 5 mg/L PFOS. A possible non-monotonic dose response was found in rUburst to PFOS. Moreover, PFOS significantly increased RMR (P<0.05), but did not have a marked effect on maximum metabolic rate (MMR), metabolic scope (MS), factorial metabolic scope (F-MS) and excess post-exercise oxygen consumption (EPOC) (P>0.05). The results indicated that PFOS had more dramatical effect on RMR than MMR of the experimental fish. Presumably, PFOS negatively impact survival-related activities such as capturing prey, avoiding predators, hunting for suitable habitats without significant ecotoxicological effects on metabolic recovery associated with anaerobic metabolism.
2019, 43(2): 362 -366   doi: 10.7541/2019.045
[Abstract](248) [FullText HTML](155) [PDF 551KB](31)
Abstract:
In order to explore activities of digestive enzymes fluctuation of common carp (Cyprinus carpio) larvae during growth stage, this study investigated the growth, soluble protein content and the activities of digestive enzymes of laboratory-reared common carp. The results indicated that total length and body weight of larvae at 40 days after hatching (DAH) increased greatly with a 14.81% growth rate. The activities of amylase, lipase, trypsin, chymotrypsin, alkaline phosphatase and aminopeptidase were detected at 1 DAH in common carp. During the development of larvae, soluble protein content of larvae decreased firstly, and then gradually increased. The activity of digestive enzymes in larvae increased before feeding. With the development of digestive systems and change of alimentation mode, activities of digestive enzymes of larvae changed continually from 3 to 25 DAH. After 25 DAH, activities of digestive enzymes of common crap were relatively stable, a sign of completed larval digestive function. In order to improve the ecological restoration effect of artificial fishnest and reduce starvation effect on the survival rate of larvae, organic materials could be used for artificial fishnest according to the digestive enzyme activity of common carp at different developmental stages.
2019, 43(2): 367 -378   doi: 10.7541/2019.046
[Abstract](132) [FullText HTML](82) [PDF 788KB](8)
Abstract:
To protect Schizothorax macropogon, belong to Schizothorax, Schizothorax, this study investigated the embryonic and larval development characteristics of Schizothorax macropogon to provide technical support for its scientific protection and rational development. The results indicated that the egg with the diameter 3.0—3.2 mm were slightly sticky when met with water and then take off the stick. The egg hatched about 460.67 hours at temperature 10℃. Based on external morphological characteristics, embryonic development was separated into 7 stages, including cleavage preparing stage, cleavage stage, blastula stage, gastrula stage, neural embryo stage, organ differentiation stage, and hatching stage. Newly hatching fry with body length 9.9—11.0 mm, heart rate 48—50 beats/min, operculum, underjaw primordial radial of tail fin primordia clearly appeared. 2-day fry after hatching, nose concave appeared. Hepatopancreas primordial observed from 3 day fry after hatching, and gill raker and shoulder strap primordium shown in 4 day fry after hatching. The upper and lower jaw began to open and close in 6 day fry after hatching, and vascular differentiation ended, turned into mixed vegetative phase at 7 day fry after hatching. 14 day fry after hatching, swim bladder one room and pigment zone formed. 26 day fry after hatching, rib primordia developed. 35 day fry after hatching, swim bladder two room formed and yolk sac depleted. 63 day fry after hatching, dorsal fin differentiation ended and lateral line developed. 83 day fry after hatching, anal fin differentiation ended. An unique development timing for the first blastopore to metameres existed in Schizothorax macropogon, which is the adaptation and evolution to plateau environment.
2019, 43(2): 379 -387   doi: 10.7541/2019.047
[Abstract](283) [FullText HTML](182) [PDF 794KB](20)
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Most Balitoridae fish with similar shapes separately distribute in different rivers or different sections of a river. Providing the morphological similarities, it’s interesting to find why Sinogastromyzon sichangensisandMetahomaloptera omeiensis coexist in the Zaodu River. To address this, the digestive systems of these two fish species were comparatively analyzed by morphological, histological and histochemical methods. The digestive systems of these two fish were nearly the same at morphology, which were consistent with characteristics of omnivorous fishes, however, the morphological difference of the digestive system was obvious. First, the intestine of S. sichangensis was circled into a" φ”shape, with hepatopancrease covered on the ventral part, however, that of M. omeiensis was organized in a complicated ways. Second, the gut index (GI) and digestive system index (DSI) of S. sichangensis were greater than those of M. omeiensis.Besides, the digestive tract of S. sichangensis had a significant higher mucosal fold and thicker muscular layer compared with M.oneiensis, however, there was no significant difference in hepatopancrease. The mucous secreting cells were similar in these two fishes based on AB (Alcian Blue) and PAS (Periodic Acid Schiff) staining, and most of these cells belong to type Ⅱ and Ⅳ mucous cells that were similar to most teleosts. The characteristics of digestive system reflect the feeding habits and digestive ability of fish, in some degree. Thus, the morphological and histological differences in digestive system between S. sichangensis and M. omeiensis may suggest different diet and digestion, which maybe the reasons for the coexistence of these two morphologically similar species.
2019, 43(2): 388 -394   doi: 10.7541/2019.048
[Abstract](267) [FullText HTML](157) [PDF 435KB](30)
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To evaluate muscle nutritive values of the hybrid F1 of female Culter alburnus × male Megalobrama terminalis (CA×MT), the proximate composition, amino acids levels, fatty acids profiles and mineral contents in muscle of Culter alburnus (CA), Megalobrama terminalis (MT), and CA×MT were measured. The results showed that muscle moisture of CA×MT were significantly lower than those of CA and MT (P<0.05), while the muscle crude protein of CA×MT was significantly higher than others (P<0.05). Muscle essential amino acids (EAA) of CA×MT was the highest one that was significantly higher than that of MT (P<0.05). According to amino acid score (AAS) and chemical score (CS), the first limiting amino acid was methionine+cysteine (Met+Cys) for all three kinds of fish. The percentage of unsaturated fatty acid (UFA) to total fatty acids of CA×MT in muscle was higher than those of CA and MT (P<0.05). The contents of iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) of three kinds of fish in muscle had no significant difference (P>0.05). In conclusion, the muscle of CA×MT has a higher nutritive value with higher protein contents, EAA and UFA.
2019, 43(2): 395 -401   doi: 10.7541/2019.049
[Abstract](112) [FullText HTML](72) [PDF 463KB](11)
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To increase feed intake and reduce feed loss in the production of Eriocher sinensis, this study screened the attractants for Chinese mitten crab by pigment indication method using crabs of (26.4±0.17) g that were equally divided into 20 concrete tankages. To explore color preference and the optimum supplement dosages of five attractants of squid extract (SE), yeast hydrolysate (YH), cottonseed meal protein hydrolysate (CPH), betaine, and allicin, these five attractants were added pigment of different colors. The results showed that color did not significantly impact on feeding of crab (P>0.05). The stimulant index of fed 0.3% SE, 0.6% YH, 0.6% CPH and 0.09% allicin diets were significantly (P<0.05) higher than that of the control diet. The highest stimulant index of betaine was 1%, but there was no significant difference among other groups (P>0.05). The highest stimulant index was observed in 0.6% CPH group, and the stimulant index of 0.6% CPH and 0.6% YH diet was significantly (P<0.05) higher than other groups. The stimulant index of 0.3% SE diet was higher than 0.09% allicin diet group and 1% betaine diet group (P<0.05). In conclusion, the optimum supplement dosages of SE, YH, CPH, betaine and allicin for crab were 0.3%, 0.6%, 0.6%, 1% and 0.09% orderly and diets preference were following: CPH>YH>SE>allicin>betaine. The 0.6% CPH or 0.6% YH had stronger attractive effect among the attractants, which can be used as attractants of crab.
2019, 43(2): 402 -414   doi: 10.7541/2019.050
[Abstract](154) [FullText HTML](60) [PDF 1145KB](16)
Abstract:
" Plate-shaped Lake Enclosed in Autumn” is a fishing method used by fishermen in the Poyang Lake. According to seasonal water level, fishermen use artificial gates to control sub-lake water level for fishing. This study analyzed the zooplankton community structure during the " Plate-shaped Lake Enclosed in Autumn” and discussed the impact of water level and other possible influencing factors on the zooplankton community structure. From 9th November, 2014 to 4th January, 2015, we conducted 8 times qualitative and quantitative zooplankton acquisitions from seven sampling sites in the open water area of Dahuchi Lake, a sub-lake located in the Poyang Lake National Nature Reserve. A total of 77 species of zooplankton were identified, which consisted of 53 species of Rotifera, 10 species of Cladocera and 14 species of Copepoda. During the " Plate-shaped Lake Enclosed in Autumn” fishing process, the specie richness of zooplankton gradually decreased with the decrease of water level. The diversity index of zooplankton also showed a decreasing tendency. Zooplankton density and biomass increased first and then decreased. However, the density variation of dominant species in zooplankton has obvious species differences. The density of Asplanchna priodonta and Limnoithona sinensis gradually increased during " Plate-shaped Lake Enclosed in Autumn”. The density of Polyarthra vulgaris, Mesocyclops leuckarti, Bosmina longirostris and Copepod nauplii continuously decreased. Redundancy analysis (RDA) showed that several environmental factors such as water level, conductivity, water temperature, dissolved oxygen and nutrient had significant effect on the zooplankton community structure with the strongest effect by dissolved oxygen. In addition, according to the information of fishing catch during " Plate-shaped Lake Enclosed in Autumn”, we propose that the decrease in planktonic fish caused by fishing activities can impact zooplankton density.
2019, 43(2): 415 -422   doi: 10.7541/2019.051
[Abstract](302) [FullText HTML](191) [PDF 899KB](41)
Abstract:
Jianghan Plain is an alluvial plain located in the middle and south of Hubei province, China. In order to explore the community structure of phytoplankton in an integrated rice-crayfish symbiosis farming (IRCSF) system, algal species, cell density, algal biomass, and physicochemical factors in four rice-crayfish symbiosis farming water bodies were monthly investigated in the Jianghan Plain from April 2016 to December 2016. There were 124 species belonged to 7 phylum, which observed in this integrated system; 78 species belonged to Chlorophyta; 16 species belonged to Cyanophyta; 15 species belonged to Bacillariophyta; 3 species belonged to Euglenophyta; 2 species belonged to Cryptophyta; 7 species belonged to Pyrrophyta; and 3 species belonged to Chrysophyta. The number of algal species, cell density value, and chlorophyll-a content all reached the maximum value from June to September, while the minimum value appeared in December. Algal cell density fluctuated in the range of 1.37×105 to 2.93×108 cells/L, and the content of chlorophyll-a varied from 0.15 to 208.60 μg/L. During the study period, 28 dominant species were totally identified. The dominant species were Oscillatoria, Dactyloccocpsis, Microcystis, Chlorella, and Cryptomonas. The annual variation of the Shannon-Wiener diversity index was from 0.64 to 6.3. The maximum value of diversity index achieved in October, while the minimum value was in August. The results showed that the community structure of phytoplankton in the IRCSF sytem was complex with an obvious spatio-temporal heterogeneity. Since algae plays an important role in water environment and crayfish cultivation, it is of great significance to pay attention to the change of community structure of phytoplankton in the IRCSF system.
2019, 43(2): 423 -430   doi: 10.7541/2019.052
[Abstract](288) [FullText HTML](188) [PDF 856KB](28)
Abstract:
Gaoyou Lake is the sixth largest freshwater lake in China, it is located between Anhui Province and Jiangsu Province. It has been located in the eastern part of the South-to-North Water Diversion Project, playing an important role in the national water allocation strategy. Base on the investigation performed on the distribution of submerged plants in Gaoyou Lake in 2016, this paper analyzed the characteristics of distribution of submerged plants, and presented a relationship between submerged plants and key environmental factors with redundancy analysis. The results showed that there were few submerged plants in Gaoyou Lake. In addition, it was revealed that Potamogeton crispus was a dominant species and prevalent in the whole lake in late spring and summer seasons, which occupied all over the lake. Myriophyllum spicatum and Potamogeton pectinatus were only visible in few sampling points as well. Nitrogen (N) content of Gaoyou Lake maintained at Ⅲ level in different seasons, whereas phosphorus severely exceeded the limit. The correlation analysis revealed that the distribution of submerged plants was positively correlated with water transparency, while negatively correlated with total phosphorus (P) and ammonium. Results of Monte Carlo analysis also showed that both the total phosphorus and water transparency were the main environmental factors playing key roles in the distribution of submerged plants in Lake Gaoyou. These results have provided a strong basis for utilization and protection of submerged plant resources in Gaoyou Lake.
2019, 43(2): 431 -438   doi: 10.7541/2019.053
[Abstract](277) [FullText HTML](181) [PDF 607KB](15)
Abstract:
We studied the effects of different amount biostimulants supplement on the removal efficiency of nitrogen, phosphorus and COD in vertical flow constructed wetland. The mechanism was analyzed by determining the activities of substrate phosphatase and urease in the constructed wetland systems. The results showed that biostimulanta suppklement could improve nitrogen removal efficiency in the systems, and the removal rates of \begin{document}${\rm{NH}}_4^ +$\end{document} -N and TN reached up to 80%, increasing by 71.5% and 31.7% respectively when compared with the control group. The maximum removal rates of TP and COD reached up to 36.0% and 91.6%, increasing by 9.1% and 5.9%, respectively. Meanwhile, the biostimulants could improve the enzymatic activities of substrate phosphatase and urease in the system, and the biostimulants had a significant influence on substrate urease activity. Significant positive relationships were found between COD removal rate and the activities of substrate phosphatase and urease. The most suitable amount of biostimulant supplement used in this system is 5 μL/L, which means 5 μL biostimulants was supplied to 1 L influent.
2019, 43(2): 439 -447   doi: 10.7541/2019.054
[Abstract](132) [FullText HTML](68) [PDF 859KB](9)
Abstract:
To evaluate the impacts of nitrogen concentration on both biomanipulation and the competition between algae and water grass, Microcystis aeruginosa, Daphnia magna and Ceratophyllum demersum were selected for experiments to represent phytoplankton, zooplankton and submerged macrophyte, respectively. When two or three of them were cultured together, the changes of growth rate and removal rate of nitrogen and phosphorus were observed with the phosphorous concentration of 1.5 mg/L and 5 different nitrogen concentrations (0.5, 2, 4, 8 and 16 mg/L, prepared with KNO3 solution), under temperature of 25℃, illumination of 2600 lx, light dark ratio 14h﹕10h. The results indicated that whenM. aeruginosa was cultured separately, its growth rate effectively reduced with a nitrogen concentration less than 1.97 mg/L. When D. magna andM. aeruginosa were co-cultured, the nitrogen concentration which D. magna could effectively control algae was from 0.5 to 4 mg/L. However, the nitrogen concentration which C. demersum could effectively control algae was from 0.5 to 2 mg/L, when C. demersum and M. aeruginosa were co-cultured. When nitrogen concentrations were at 0.5 and 2 mg/L, the cell densities of M. aeruginosa were 23.89% and 21.51%, respectively, of that when D. magna and M. aeruginosa were co-cultured at the last of experiment. So the effect of algae control was better when C. demersum and M. aeruginosa were co-cultured. The algae could be effectively controlled with nitrogen concentration from 0.5 to 16 mg/L, when D. magna, C. demersum and M. aeruginosa were co-cultured, under which the effect of algae control was the best. Especially, the growth rate of M. aeruginosa was all negative and significantly lower than those of D. magna and C. demersum when nitrogen concentration was bewteen 0.5 and 4 mg/L. In the co-culture environment of D. magna and M. aeruginosa, with the addition of large submerged macrophyte, the effect of algae control could effectively enhance, and the nitrogen and phosphorus in the water could be decreased, which can effectively improve the water quality over the long term.
2019, 43(2): 448 -456   doi: 10.7541/2019.055
[Abstract](283) [FullText HTML](83) [PDF 464KB](37)
Abstract:
The structure and function of microbial communities in aquatic ecosystems have been widely reported. In eutrophic waters, bacteria play an important role in the occurrence, development, decline and degradation of Microcystis blooms. In this paper, we described the unique characteristics ofMicrocystisand bacterial communities in the water column and sediment, as well as the responses of the dynamics of Microcystis and bacterial communities to environmental factors. Furthermore, the interactions between Microcystis and bacteria were summarized from the following aspects: first, attached bacteria can mediate the growth of Microcystis in the microenvironment of algal cells. Second, bacteria are involved in the formation and maintenance of Microcystis colonies. Third, bacteria regulate the aggregation and degradation of Microcystis blooms. Fourth, the bacterial degradation of microcystins was introduced. Finally, the future research focus of the relationships betweenMicrocystisand bacteria and the available omics technology were prospected.

### 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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