淡水养殖太平洋鲑循环饥饿后补偿性生长效果研究

COMPENSATORY GROWTH AFTER EXPERIENCING CYCLES OF FEED DEPRIVATION AND RE2FEEDING IN PACIFIC SALMON, ONCORHYNCHUS SPP

  • 摘要: 用16.1%脂肪,38.1%蛋白质含量日粮饲养108尾初始重约为240g的太平洋鲑(Oncorhynchusspp.)于0.25m3的水族箱中64d,水温为15.5±3.7℃。实验分6组,分别为对照组(每天投喂),实验1组(隔天投喂),实验2组(隔2天投喂2天),实验3组(隔4天投喂4天),实验4组(隔8天投喂8天),实验5组(隔16天投喂16天)。每组设3个平行水族箱,每箱6尾鱼。研究淡水养殖太平洋鲑多重周期饥饿后补偿性生长效果。实验结果表明:(1)各试验组太平洋鲑成活率均为100%。实验1、2、3组太平洋鲑鱼体增重接近对照组,其恢复摄食期间特定生长率、摄食率、食物转化率均显著或极显著高于对照组(P0.05或0.01)。而实验4、5组鱼恢复摄食期间虽摄食率极显著高于对照组(P0.01),但其鱼体增重、特定生长率、食物转化率均极显著低于对照组(P0.01);(2)实验各组鱼肥满度、肝体比、肝脏脂肪和糖原含量、肌肉中脂肪含量较对照组均有不同程度下降,肝脏脂肪中总饱和脂肪酸比例上升,而总多不饱和脂肪酸比例下降;(3)实验1、2、3组血浆中甘油三酯、胆固醇和低密度脂蛋白显著低于对照组,而葡萄糖、血清中甲状腺激素T4浓度显著高于对照组(P0.05)。实验结果表明,初重约240g太平洋鲑饥饿1-4d,再循环投喂相同时间64d后,获得了接近完全补偿生长效果,表现为其恢复摄食期间摄食率和食物转化率明显上升,生长速率明显加快,饲料报酬明显提高,鱼体增重接近持续喂食的对照组,养殖效益明显提高。但饥饿8-16d再循环投喂相同时间后,表现为无补偿生长效应,食物转化率和生长速率明显下降,鱼体增重极显著低于持续喂鱼的对照组。

     

    Abstract: A 64-days compensatory growth experiment in Pacific Salmon, Oncorhynchus spp. was conducted to determine the ef-fects of growth following starvation infreshwater. 108 Pacific salmon (initial weight ca.240g) were divided into 6 treatments with triplicate groups in a recirculated system at 15.5 ± 3.7 ℃. The control fishes were fed continuously and the test fishes were expe-riencing 1day deprivation and 1 day re2feeding,2 days deprivation and 2 days re-feeding, or 4,8,16 days deprivation and 4,8, 16 days re-feeding. The results indicated that the survival rate (SR) of fish in all groups is 100 % and the weight-gain in fish of test group 1,2,3 is close to fish at the control group, but fish in test group 4, 5 are significantly lower than those of the control group. The specific growth rate (SGR),feeding rate (FR),feed efficiency (FE) of fish in test group 1,2,3 were significantly higher than those of the control group (P < 0.05 or 0.01),but fish in test group 4,5 were significantly lower than those in the control group (P < 0.01). The condition factor (CF) and the rate of liver/ body,content of lipid and glycogen in liver, content of lipid in muscle of fish in all test groups were in different degree lower thanfish in the control group. The ratio of total saturated fatty acids(ΣSFA)in lipidof liver withfish in test groups was higher and total polyunsaturatedfatty acid (ΣPUFA) was lower than fish in the control group. The indexes of triglyceride(TG), cholesterol (CHOL),low density lipoprotein (LDL2C) in plasma of fish in test group 1,2,3 were significantly lower than those in the control group, but glucose in plasma and thyroxine T4in serum were significantly higher than those in the control group (P < 0.05). These results suggested that Pacific salmon with initial weight ca. 240g, which were deprivedfeedfor 1,2,4 days and then were re-fed for same days subsequently during 64 days peri-od, showed a positive compensatory growth through raising the feeding rate (FR) and feed efficiency (FE),but the fish which were deprived feed for 8-16 days and then were re2fed same days during the same period, showed a negative compensatory growth due to decrease of feeding rate (FR) and feed efficiency(FE).

     

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