红鳍东方鲀幼鱼适宜投喂频率和投喂水平的研究

Study on Optimum Feeding Frequency and Feeding Level of Juvenile Takifugu rubripes

本试验旨在研究投喂频率和投喂水平对红鳍东方鲀幼鱼生长、饲料利用、形体指标、体成分、消化酶活性和水质的影响,以确定红鳍东方鲀幼鱼适宜投喂频率和投喂水平。在流水养殖模式下,采用商业饲料分别进行投喂频率和投喂水平的摄食生长试验。投喂频率试验为表观饱食投喂,设2、3和4次/d共3个投喂频率,分别记为F2、F3和F4组;投喂水平试验采用3次/d的投喂频率,设体重的2%、4%、6%、8%和10%共5个投喂水平,分别记为R2、R4、R6、R8和R10组。选择红鳍东方鲀初始体重约15 g的幼鱼,每组3个重复,每个重复30尾鱼,进行28 d养殖试验。结果表明:1)不同投喂频率对终末体重、成活率、摄食率(FI)、特定生长率(SGR)和饲料效率(FER)均无显著影响(P>0.05)。R2组FI、SGR和FER显著低于R4、R6、R8、R10组(P<0.05)。2)F3组肝体比(HSI)和脏体比(VSI)显著高于F2组(P<0.05)。R2组HSI显著低于R4、R6、R8、R10组(P<0.05);R2组VSI显著低于R8和R10组(P<0.05),但与R4和R6组无显著差异(P>0.05)。3)F3组肝脏胰蛋白酶和脂肪酶活性显著高于F2和F4组(P<0.05)。R2组肝脏胰蛋白酶活性显著低于R4、R8和R10组(P<0.05);R2组肝脏糜蛋白酶活性显著高于R4、R6、R8、R10组(P<0.05);R2组肝脏脂肪酶活性显著低于R4组(P<0.05),但与R6、R8和R10组无显著差异(P>0.05)。4)F3组肝脏谷丙转氨酶(ALT)活性显著低于F2组(P<0.05)。R2组肝脏ALT活性显著低于R4和R10组(P<0.05),但与R6和R8组无显著差异(P>0.05)。5)尽管氨态氮、亚硝态氮和磷酸盐含量在养殖水桶出水口相比进水口数值上大部分有所升高,但不同投喂频率和投喂水平对养殖水体中的氨态氮、亚硝态氮和磷酸盐含量均无显著影响(P>0.05)。由此可见,在本试验条件下,红鳍东方鲀幼鱼适宜的投喂频率为2~3次/d,投喂水平为体重的4%。此外,在流水养殖模式下,不同投喂频率和投喂水平对养殖水体氨态氮、亚硝态氮和磷酸盐含量的影响极小。

The aim of this study was to investigate the effect of feeding frequency and feeding level on growth,feed utilization,morphological parameters,body composition,digestive enzyme activities and water quality of juvenile Takifugu rubripes,and to determine the suitable feeding frequency and feeding level of juvenile Takifugu rubripes.Under the flow-through rearing system,the feeding growth experiments for feeding frequency and feeding level were tested with commercial feed.The feeding frequency experiment was apparent satiety feeding,which set 3 feeding frequencies of 2,3 and 4 times/d,and named F2,F3 and F4 groups,respectively;the feeding level experiment used the feeding frequency of 3 times/d,which set 5 feeding levels of 2%,4%,6%,8%and 10%body weight,and named R2,R4,R6,R8 and R10 groups,respectively.Juvenile Takifugu rubripes with initial body weight about 15 g were selected,each group contained 3 replicates and each replicate contained 30 fish.The experiment lasted for 28 days.The results showed as follows:1)the final body weight,survival rate,feed intake(FI),specific growth rate(SGR)and feed efficiency ratio(FER)were not significantly affected by different feed frequencies(P>0.05).The FI,SGR and FER of R2 group were significantly lower than those of R4,R6,R8 and R10 groups(P<0.05).2)The hepatosomatic index(HSI)and viscerosomatic index(VSI)of F3 group was significantly higher than those of F2 group(P<0.05).The HSI of R2 group was significantly lower than that of R4,R6,R8 and R10 groups(P<0.05);the VSI of R2 group was significantly lower than that of R8 and R10 groups(P<0.05),but had no significant difference with R4 and R6 groups(P>0.05).3)The activities of trypsin and lipase in liver of F3 group were significantly higher than those of F2 and F4 groups(P<0.05).The liver trypsin activity of R2 group was significantly lower than that of R4,R8 and R10 groups(P<0.05);the liver chymotrypsin activity of R2 group was significantly higher than that of R4,R6,R8 and R10 groups(P<0.05);the liver lipase activity of R2 group was significantly lower than that of R4 group(P<0.05),but had no significant difference with R6,R8 and R10 groups(P>0.05).4)The liver alanine aminotransferase(ALT)activity of F3 group were significantly lower than that of F2 group(P<0.05).The liver ALT activity of R2 group was significantly lower than that of R4 and R10 groups(P<0.05),but had no significant difference with R6 and R8 groups(P>0.05).5)The contents of ammonia nitrogen,nitrite nitrogen and phosphate from water inlet of tanks were higher than those from water outlet after 2 h of feeding,but different feeding frequencies and feeding levels had no significant effects on contents of ammonia nitrogen,nitrite nitrogen and phosphate in aquaculture water(P>0.05).In conclusion,under the present experimental condition,the optimal feeding frequencies of juvenile Takifugu rubripes are 2 to 3 times/d,and the feeding level is 4%body weight.In addition,under the flow-through rearing system,different feeding frequencies and feeding levels have minimal impact on the contents of ammonia nitrogen,nitrite nitrogen and phosphate in the aquaculture water.