The Lipid(Energy) To Protein Ratio And Lipid Content Of Juvenile Blunt Snout Brean(Megalobrama Amblycephala)

A series of two experiments was conducted to study to the optimum levels ofdietary lipid to protein ratio and lipid on juvenile blunt snout brean by feeding differrentdietary lipid to protein ratio and lipid after51d’ s feeding trial.Experiment1: the optimal level of lipid on juvenile blunt snout breanSix experimental diets containing2.7%,4.1%,5.6%,7%,8.4%,9.9%were fed totriplicate groups of20fish with intial mean weights of6.89g for51days.The resultssuggested that the conic analysis of WG,SGR,FCR,PER and PDR indicated that theoptimal dietary lipid of juvenile blunt snout brean was3.60%,3.61%,3.72%,4.39%and4.71%when WG,SGR,FCR,PER and PDR arrived in the maximum. Compared with2.7%and4.1%,when the dieriay lipid added in the level of9.9%,viscerosomatic indexwas significantly increased(P<0.05),but the condition factor and hepatopancrea indexshowed no significant difference (P>0.05);the body composition showed no significantdifference (P>0.05);the ALT,AST/ALT, TCHO,TRIG,HDL-C,LDL-C,T-SOD in bloodand MDA in intestine were not significantly different (P>0.05),but when the dieriaylipid added in the level of9.9%(P<0.05), the GLU reached the lowest level. Comparedwith2.7%and4.1%,when the dieriay lipid added in the level of7%,the AST in bloodand MDA in liver were significantly increased(P<0.05).For muscle,the fatty acidcomposition was reflected to a certain extent by dietary fatty acid composition. C18:1n-9was the main fatty acid in muscle and liver lipid.Fish was the ability to convert fattyacids of dietary.This convertion occurred between n-3and n-6fatty acids.Liver cell wasin the nomal location when the lipid level reached2.7%and4.1%,but fat accumulationis further increased with the growing lipid content level in other groups, In summary, itwas advised that the optimal lipid level of juvenile blunt snout brean was3.60%~4.71%.Experiment2: the optimal dietary lipid to protein ratio on juvenile blunt snout breanAn experiment was performed to study the optimal dietary lipid to protein ratio ofjuvenile blunt snout. Six crude protein levels (36%,34%,32%,30%,28%,26%) wereutilized.Correspondingly,lipid to protein ratios were0.08,0.12,0.18,0.23,0.3,0.38.Casein, gelatin and Peruvian fish meal were used as the source of protein.Lipid sourcewas soybean oil. Each of the experimental diets was fed to triplicate groups of20fishwith an average individual weight of6.89g for51days.The result showed that the conicanalyses of WG,SGR,FCR,PER,PDR and ERR indicated that the optimal dietary lipidto protein ratio of juvenile blunt snout brean was0.17,0.17,0.17,0.26,0.31,0.22. whenWG,SGR,FCR,PER,PDR and ERR arrived in the maximum. Compared to other groups,when the dietary lipid to protein ratio added in the level of0.38, the conditionfactor,viscerosomatic index,hepatopancrea index were significantly increased (P<0.05);the body composition showed no significant difference (P>0.05); The AST, ALTAST/ALT, GLU, TCHO, TG, HDL-C, LDL-C,T-SOD in blood and MDA in intestinewas not significantly different (P>0.05). The MDA is further increased with the growingdietary lipid to protein ratio level,compared with0.08,0.12,0.18, and0.23,when thedietary lipid to protein ratio added in the level of0.3,the MDA in liver was significantlyincreased(P<0.05).The amino acids correlation coefficients of the experimental dietsand muscle of their corresponding experimental groups were between0.92to0.96, andhad not significantly different(P>0.05).When dietary lipid to protein ratio reached0.3,the hepatopancreas cell began to apoptosis, bile duct began to cholestasis. With thecombination of these conclusions, it was recommended that the optimal lipid to proteinratio of juvenile blunt snout brean was0.17to0.26(lipid content from5.56%to7.70%,protein content from29.60%to32.72%).