| 3 feeding trials were conducted to examine the effects of lysine,methionine,arginine,and taurine on feeding,growth performence,body composition,serum and liver biochemical indices of tiger puffer(Takifugu rubripes).the results of these studies are shown as follows:1.Dietary lysine requirement of juvenile tiger puffer(Takifugu rubripes)A 76-days feeding experiment was conducted to investigate how the diet with different lysine influenced the growth performance and biochemical parameters of tiger puffer(average body weight:13.83±0.63g),and to determine the dietary lysine requirement for tiger puffer.There were six experimental isonitrogenous and isolipidic semipurified diets which were formulated with the graded levels of methionine(1.65%,2.58%,3.18%,4.01%,4.80%,5.52%,respectively).Each diet was randomly assigned to triplicate groups,and each group contained 30 individuals.Fish were fed fourth daily(07:00,12:00,16:00,20:00)to apparent satiation.The result showed that no significant differences in Protein efficiency ratio(PER)were found among dietary treatments(P>0.05).Specific growth rate(SGR),feed conversion ratio(FCR)and Protein productive value(PPV)increased with increasing dietary lysine levels from1.65% to 4.80%(P<0.05),the higest group was observed in lysine levels 4.80% group,and there after showed a declining tendency with increasing dietary lysine levels from4.80 to5.52% ? Crude lipid,Hepatosomatic index(HSI)and viscerosomatic index(VSI)of the 1.65% lysine diets was significantly higher than other groups(P<0.05).while moisture,crude protein and condition factors(CF)showed no significant differences(P>0.05).Dietary lysine levels significantly influenced the contents of high density lipoprotein cholesterol,total protein and activity of glutamic-oxaloacetic transaminase,alkaline phosphatase in serum(P<0.05),There were no significant difference in total cholesterol,low density lipoprotein cholesterol,triglyceride,bile acid,blood glucose and activity of glutamic-pyruvic transaminase(P>0.05)in serum.Second-order regression analysis on the basis of specificgrowth rate(SGR)indicated that the optimum dietary lysine requirements of tiger puffer were estimated to be 3.95% of diet(7.89% of dietary protein).2.Dietary methionine requirement of juvenile tiger puffer(Takifugu rubripes)A 76-days feeding experiment was conducted to investigate how the diet with different methionine influenced the growth performance and biochemical parameters of tiger puffer(average body weight:13.83±0.63g),and to determine the dietary methionine requirement for tiger puffer.There were six experimental isonitrogenous and isolipidic semipurified diets which were formulated with the graded levels of methionine(0.61%,0.85%,1.10%,1.39%,1.60%,1.84%,respectively).Each diet was randomly assigned to triplicate groups,and each group contained 30 individuals.Fish were fed fourth daily(07:00,12:00,16:00,20:00)to apparent satiation.The result showed that no significant differences in protein productive value(PPV)were found among dietary treatments(P>0.05).Specific growth rate(SGR),feed conversion ratio(FCR)and protein efficiency ratio(PER)increased with increasing dietary methionine levels from 0.61% to 1.60%(P<0.05),the higest group was observed in methionine levels1.60% group,and there after showed a declining tendency with increasing dietary methionine levels from1.60% to 1.84%?Hepatosomatic index(HSI)and viscerosomatic index(VSI)of the 1.60% methionine diets was significantly higher than that of 0.61%groups(P<0.05),with further increase from 1.60% to 1.84%,HSI and VSI decreased.The crude lipid contents of whole body were significantly affected by dietary methionine levels(P<0.05),the 1.60% methionine diets was significantly higher than0.61% groups(P<0.05),with further increase from 1.60% to 1.84%,crude lipid decreased.while moisture,crude protein and ash showed no significant differences(P>0.05).Dietary methionine levels significantly influenced the contents of triglyceride,bile acid and blood glucose in serum(P<0.05),There were no significant difference in total cholesterol,high density lipoprotein cholesterol,low density lipoprotein cholesterol,total protein,activity of glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase(P>0.05)in serum.Second-order regression analysis on the basis of specific growth rate(SGR)indicated that the optimum dietary methionine requirements of tiger puffer were estimated to be 1.38% of diet(2.71% of dietary protein).3.Dietary methionine increased the lipid accumulation in juvenile tiger puffer Takifugu rubripesMethionine(Met)is one of the most important amino acids in fish feed.The effects of dietary Met on lipid deposition in fish varied a lot among different studies.The present study was aimed at investigating the effects of dietary Met supplementation on the lipid accumulation in tiger puffer,which have a unique lipid storage pattern.Crystalline L-Met was supplemented to a low-fishmeal control diet to obtain two experimental diets with a low(1.1% of dry weight,L-MET)or high Met level(1.6% of dry weight,H-MET).A 76-day feeding trial was conducted with juvenile tiger puffer(average initial weight,13.83 g).Each diet was fed to triplicate tanks(30 fish in each tank).The results showed that the total lipid contents in whole-body and liver significantly increased with increasing dietary Met levels.The hepatosomatic index,weight gain,and total bile acid content in serum showed similar patterns in response to dietary Met treatments,while the lipid content in muscle was not affected.The hepatic contents of 18-carbon fatty acids were elevated by dietary Met supplementation.The Hepatic mRNA expression of lipogenetic gene such as FAS,GPAT,PPAR?,ACLY,and SCD1 was down-regulated,while the gene expression of lipolytic genes ACOX1 and HSL,as well as that of ApoB100,were up-regulated by increasing dietary Met levels.The hepatic lipidomics of experimental fish was also analyzed.In conclusion,increasing dietary Met levels(0.61%,1.10%,and 1.60%)increased the hepatic lipid accumulation in tiger puffer.The mechanisms involved warrant further studies4.Effects of dietary arginine on growth performance,body composition and gene expression related to TOR signal pathway of juvenile tiger puffer(Takifugu rubripes)A 56-days feeding experiment was conducted to investigate how the diet with different arginine influenced the growth performance and biochemical parameters of tiger puffer(average body weight:19.97±0.14g),and to determine the dietary arginine requirement for tiger puffer.There were six experimental isonitrogenous and isolipidic semipurified diets which were formulated with the graded levels of arginine(1.91%,2.15%,2.44%,2.67%,3.00%,3.25%,respectively).Each diet was randomly assigned to triplicate groups,and each group contained 25 individuals.Fish were fed third daily(08:00,14:00,20:00)to apparent satiation.The result showed that no significant differences in feed intake(FI)were found among dietary treatments(P>0.05).Specific growth rate(SGR),feed conversion ratio(FCR),protein productive value(PPV)and protein efficiency ratio(PER)increased with increasing dietary arginine levels from1.91% to 2.44%(P<0.05),the higest group was observed in arginine levels 2.44%group,and there after showed a declining tendency with increasing dietary arginine levels from2.44% to 3.25% ? There were no significant difference in Hepatosomatic index(HSI),viscerosomatic index(VSI),condition factor(CF),crude lipid,crude protein,ash,moisture(P>0.05).Dietary arginine levels significantly influenced the contents of TNOS and activity of glutamic-pyruvic transaminase(GPT)in liver(P<0.05),and also influenced the contents of GOT,SOD,GSH,LZM in serum(P<0.05).broken-line regression analysis on the basis of SGR,FCE,PER,PPV indicated that the optimum dietary arginine requirements of tiger puffer were estimated to be 2.27%-2.44% of diet(4.70%-5.05 of dietary protein). |
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