Research On Optimal Ratio Of Dietary Protein,Lipid And Carbohydrate For Siganus Guttatus

The purpose of research was to determine optimal ratio of dietary protein,lipid andcarbohydrate for Siganus guttatus,the content of research as follows:1. Research on optimal ratio of dietary protein,lipid and carbohydrate for Siganusguttatus1320artificially cultured S. guttatus in weight of (6.43±0.17) g were randomlydivided into44groups in net cages at a rate of30individuals per cage, and21formulated diets were designed in this experiment, the ranges of dietary protein, lipidand carbohydrat were designed between27%～45%,3%～18%and15%～24%,respectively. Among them,20diets had two replicates per diet, and one diet with fourreplicates as the central group to calibrate bias. The test lasted for56days.The results indicated that dietary protein level was vitally important on specificgrowth rate and weight gain rate of S. guttatus, followed by dietary lipid level andcarbohydrate level. When dietary protein level was inferior to40.38%, the growthperformance of S. guttatus was adverse whether dietary lipid levels and carbohydratelevels increase or decrease. when dietary protein level exceed43.75%, the groups withhigh-protein,low-lipid and low-carbohydrate diets couldn’t significantly improvegrowth performance. When dietary protein level was40.38%～42.49%, lipid level was6.33%～7.87%and carbohydrate level was19.52%～21.14%, the growth performanceand feed efficiency were ideal. The analysis of muscle component showed thatappropriate protein amount of dietary could deposit muscles of S. guttatus when dietaryprotein levels were greater than38.44%. High-protein,low-lipid and low-carbohydratediets couldn’t significantly improve the deposition of muscle protein, but the depositionof lipids and glycogens increased.The comprehensive experimental results on growthperformance and muscle composition indicated that the best formulated dietary protein,lipid, carbohydrate for S. guttatus should be42.49%,6.33%and21.14%, respectively.2. Compared Artificial diets with commercial diets for the growth performance of Siganus guttatusThis experiment choosed five diets which included2groups of self-made optimalmacronutrient composition of diets and three commercial diets (dietary of shrimp,dietary of Epinephelussp, dietary of Trachinotus ovatus), to investigate the growthperformance,muscle quality and enzyme activity in liver of S. guttatus with15.27±1.45g. Three kinds of commercial fish diets were marked as D1, D2and D3. Every diet hadtwo replicates per diet, every replicatethe was feed to30fishes.The experiment lasted10weeks.The results showed that the SGR and WGR of S.guttatus were the lowest in D1,there were no obvious differences betwwen L9and D1(P＞0.05),but significantly lowerthan L10, D2and D3(P＜0.05). The SGR and WGR of of S.guttatus in D2were thelargest. However, the SGR and WGR of S.guttatus between L10, D2and D3had nosignificant differences (P＞0.05). The FCR of S.guttatus in D2was significantly lowerthan the other4groups (P＜0.05), L10and D3was significantly lower than that ofL9and D1(P＜0.05), the FCR of D1was up to1.64. Calculated from the diets rawmaterial costs, the price of diet ingredients in L9was minimum,secondly was L10, theprice of diet ingredients in D2was the highest.Every dietary effcts on CF, VSI, MFI andHIS of S.guttatus had no significant differences(P＞0.05).VSI, MFI and HIS ofS.guttatus in D1were the largest.The results of muscle moisture content and lipidcontent were not affected with different dietary composition (P＞0.05), muscleprotein of S.guttatus in L10and D2were significantly higher than that in L9and D1(P＜0.05), but that had no significant differences compared with D3(P＞0.05). InD1, the delicious amino acids, no essential amino acids,essential amino acids andtotal amino acids in muscle were the lowest, which in L9and D1were significantlylower than that in L10, D2and D3groups(P＜0.05), there were no significantdifferences between L10, D2and D3(P＞0.05). MUFA, PUFA and total fatty acidscontent of muscle had no significant differences in five diets(P＞0.05). In D2, HUFA ofmuscle in S.guttatus was significantly higher than that of muscle in the other fourdiets (P＜0.05), followed was L10. Among them, n-3HUFA in D2was significantlyhigher than that in L9, L10, D1and D3(P＜0.05), L10was significantly higher than thatin L9, D1and D3(P＜0.05). In L10,two types enzyme activity in liver were thehighest. liver GPT activity of S.guttatus had no significant differences in different diets(P＞0.05), L9was the lowest. Liver GOT activity in D3was significantly lower than the other four groups (P＜0.05).