Study On The Requirements Of Lysine, Methionine, Arginine And Phenylalanine For Juvenile Pacific White Shrimp, Litopenaeus Vannamei

In the present study, feeding trials were conducted to evaluate the requirements oflysine, methionine, arginine and phenylalanine for juvenile Pacific white shrimp,Litopenaeus vannamei, and evaluated the effect on growth performance, feed efficiency,the activities of amino acids metabolic enzymes and oxidation resistance for the shrimps.The results can be briefly summarized as follows:1. An8-week feeding trial was conducted to estimate the dietary lysine requirement ofjuvenile Pacific white shrimp Litopenaeus vannamei. Six isonitrogenous and isolipidicpractical diets (41.0%crude protein and7.5%crude lipid) were formulated to contain sixgraded dietary lysine levels ranged from1.44%to2.49%(dry weight) at about0.3%increments(1.44%,1.61%,1.85%,1.99%,2.23%,2.49%). The initial body weight was about0.52g. The results indicated that weight gain(WG), specific growth rate(SGR), Feedefficiency (FE) and protein efficiency ratio(PER) were significantly differences in among alltreatments(p<0.05). WG and SGR were increased significantly with the dietary lysineincrease from1.44%to1.85%, but dietary lysine from1.99%to2.49%, WG and SGR didnot increase significantly. However, protein productive ratio(PPV) were no significantlydifference(p>0.05). There were no significant differences in the compositions of whole bodyand muscle (moisture, crude protein, crude lipid and ash)(p>0.05) except for the crudeprotein of whole body. The crude protein of whole body fed2.23%lysine diet was higherthan that of other treatments. Urea nitrogen and total protein in haemolymph were notsignificantly(p>0.05), but cholesterol and triglyceride was significantly affected by theexperimental diets(p<0.05), and negative correlation with dietary lysine levels. Aspartateaminotransferase(AST) and alanine aminotransferase(ALT) in haemolymph weresignificantly affected by dietary lysine levels(p<0.05); Superoxide dismutase (SOD) andarginase in haemolymph showed no significant differences(p>0.05). The optimal dietarylysine requirement estimated by broken-line model based on SGR was2.05%of dry diet(4.92%dietary protein).2. An8-week feeding trial was conducted to evaluate the effect of dietary methioninerequirement of juvenile Pacific white shrimp Litopenaeus vannamei. Six isonitrogenous andisolipidic practical diets(41.0%crude protein and7.5%crude lipid) were formulated tocontain six graded dietary methionine levels ranged from0.59%to1.25%(dry weight) at about0.15%increments(0.59%,0.69%,0.86%,0.99%,1.10%,1.25%). The initial bodyweight was about0.34g. The results indicated that there were significantly differences inweight gain(WG), specific growth rate(SGR), feed efficiency(FE) and protein efficiencyrate(PER) among all treatments(p<0.05), but protein productive value(PPV) were nosignificantly affected by the dietary methionine level(p>0.05). With the dietary methioninewas0.86%, WG, SGR, FE and PER were significantly higher than other treatments, butdietary methionine from0.59%to0.86%, WG and SGR were increased with methionineincreased，and the decreased with the dietary methionine from0.99%to1.25%. The Wholebody composition were not significantly affected by the dietary methionine(p>0.05). Themoisture, crude protein and ash of muscle were also no significantly differences, but thecrude lipid was significantly affected by the dietary methionine(p<0.05), and were positivecorrelation with SGR. Total protein in hemolymph were significantly affected(p<0.05), buturea nitrogen, triglyceride and cholesterol in hemolymph were not significantlydifferent(p>0.05). Aspartate aminotransferase(AST), alanine aminotransferase(ALT) andsuperoxide dismutase(SOD) in hemolymph were significantly affected by dietarymethionine levels(p<0.05), Aspartate aminotransferase(AST) in the treatment which dietarymethionine is1.25%were significantly higher than other treatments, and alanineaminotransferase(ALT) were positive correlation with the dietary methionine. The activitiesof superoxide dismutase (SOD) from0.86%to1.10%were significantly higher than othertreatments(p<0.05). Arginase in hemolymph was no significantly affected by differencedietary methionine levels(p>0.05). The optimal dietary methionine requirement estimated byquadratic regression model based on SGR was0.89%of dry diets based on SGR (2.16%dietary protein).3. An8-week feeding trial was conducted to evaluate the effect of dietary argininerequirement of juvenile Pacific white shrimp Litopenaeus vannamei. Six isonitrogenous andisolipidic practical diets(41.0%crude protein and7.5%crude lipid) were formulated tocontain six graded dietary arginine levels ranged from1.44%to2.74%(dry weight) at about0.3%increments(1.44%,1.74%,1.99%,2.32%,2.51%,2.74%). The initial body weight wasabout0.50g. The results indicated that there were significantly differences in weightgain(WG), specific growth rate(SGR), feed efficiency(FE) and protein productivevalue(PPV) among all treatments(p<0.05). But with the increase of dietary arginine from1.44%to2.32%, WG, SGR, FE and PPV were significantly increased. The Whole body andmuscle composition(moisture, crude protein, crude lipid and ash) were not significantlyaffected by the dietary arginine(p>0.05). Total protein in hemolymph were significantlyaffected(p<0.05), but urea nitrogen, triglyceride and cholesterol in hemolymph were not significantly different(p>0.05). Aspartate aminotransferase(AST), alanine aminotransferase(ALT) in hemolymph were significantly affected by dietary arginine levels(p<0.05),superoxide dismutase (SOD), arginase in hemolymph were also significantly affected bydifference dietary arginine levels(p<0.05), and with dietary arginine2.32%weresignificantly higher than other treatments. The optimal dietary arginine requirementestimated by quadratic regression model based on SGR was2.16%of dry diets based onSGR(5.27%dietary protein).4. An8-week feeding trial was conducted to evaluate the effect of dietary phenylalaninerequirement of juvenile Pacific white shrimp Litopenaeus vannamei. Six isonitrogenous andisolipidic practical diets(41.0%crude protein and7.5%crude lipid) were formulated tocontain six graded dietary phenylalanine levels ranged from1.38%to2.28%(dry weight) atabout0.2%increments(1.38%,1.57%,1.82%,1.95%,2.10%,2.28%), and dietary tyrosinelevel was0.84%. The initial body weight was about0.38g. The results indicated that therewere no significantly differences in survival rate, feed efficiency(FE) and protein efficiencyrate(PER)(p>0.05). When phenylalanine were from1.38%to1.82%, weight gain(WG),specific growth rate(SGR) and protein productive value(PPV) were positive correlation withphenylalanine content. But with the dietary phenylalanine was beyond1.95%, WG, SGR andPPV were no higher. The composition of whole body and muscle(moisture, crude protein,crude lipid and ash) were not significantly affected by the dietary phenylalanine(p>0.05).Total protein, urea nitrogen, triglyceride and cholesterol in hemolymph were notsignificantly different(p<0.05). Alanine aminotransferase(ALT) were significantly affectedby dietary phenylalanine levels(p<0.05), aspartate aminotransferase(AST), superoxidedismutase(SOD) and arginase in hemolymph were no significantly affected(p>0.05), andsuperoxide dismutase(SOD) of the dietary phenylalanine1.95%were higher than othertreatments. The optimal dietary phenylalanine requirement estimated by broken-line modelbased on SGR was1.92%of dry diets based on SGR(4.54%dietary protein). Consideringthe requirement of phenylalanine by the influence of the dietary tyrosine content, and thetyrosine in experiment diets were0.84%, the total aromatic amino acids requirement ofLitopenaeus vannamei was2.76%(6.52%dietary protein).