The Study On The Optimum Dietary Vitamin B₂,Vitamin B₆ And Folic Acid Requirement Of Juvenile Golden Pompano?Trachinotus Ovatus?

The purpose of this study was to investigate the optimum dietary vitamin B₂,vitamin B₆ and folic acid of juvenile golden pompano?Trachinotus ovatus?on the basis of growth parameters,serum biochemical indices and hepatic concentration of vitamin.The main results were as below.1.The dietary vitamin B₂ requirement of juvenile golden pompano?Trachinotus ovatus?To determine the optimal dietary vitamin B₂ requirement of juvenile golden pompano?Trachinotus ovatus?,six experimental diets were formulated which contained 0 mg·kg^-1,4.4 mg·kg^-1,6.2 mg·kg^-1,8.0 mg·kg^-1,11.3 mg·kg^-1 and 15.5mg·kg^-1 of vitamin B₂.Each diet was assigned to three parallels of 25 fish[initial mass of?11.63±0.17?g]which were fed twice daily for eight weeks.The results show that the weight gain rate and specific growth rate of the fish fed with diet of 4.4mg·kg^-1 vitamin B₂ were significantly higher than those of 0 mg·kg^-1 group?P<0.05?,and the activities of aspartate aminotransferase and alanine aminotrans-ferase in the serum were significantly lower than those in 0 mg·kg^-1 group?P<0.05?.No significant effect was found on the fish coefficient,hepatic concentration of vitamin B₂,serum immune parameters,crude protein and crude fat content in whole body,moisture,crude fat and crude ash in muscle?P>0.05?;the liver D-AAO activity in 6.2 mg·kg^-1group was significantly higher in 0 mg·kg^-11 group?P<0.05?.Broken-line model analysis estimates that the dietary vitamin B₂ requirement of juvenile golden pompano is 4.23 mg·kg^-1 for optimal growth,and 6.24 mg·kg^-1 for maximum liver D-AAO activity.2.The dietary vitamin B₆ requirement of juvenile golden pompano?Trachinotus ovatus?The feeding trial was conducted to investigate the effect of dietary vitamin B₆ on growth performance,feed utilization,serum biochemical indices,hepatic antioxidant abilities,intestinal enzymes activity and intestinal flora in juvenile golden pompano?Trachinotus ovatus?.Purified basal diets were formulated by using vitamin-free casein as the main source of protein.A basal diets supplemented with vitamin B₆ at 0,3.75,7.47,10.6,13.7 and 18.5 mg·kg^-1,respectively.Each diet was randomly assigned to three replicate groups of juvenile golden pompano?initial weight15.31±0.19 g?.Weight gain rate?WGR?and specific growth rate?SGR?were the highest when dietary vitamin B₆ levels up to 7.47 mg·kg^-1.Dietary vitamin B₆ level had a significant effect on hepatic alanine aminotransferase?ALT?,aspartate aminotransferase?AST?,glutathione peroxidase?GPx?,glutathione reductase?GR?,malondialdehyde?MDA?and peroxidase?POD?activities and liver vitamin B₆concentration?P<0.05?.Golden pompano fed diet containing 7.47 mg·kg^-1 vitamin B₆achieved the maximum ALT,AST,GPx and hepatic vitamin B₆ concentrations as well as the minimum MDA,however,the ALT,AST,GPx and hepatic vitamin B₆concentrations decreased while MDA increased with a further increasing of dieatry vitamin B₆.The highest values of GR and POD occurred at the 10.6 mg·kg^-1 and 13.7mg·kg^-1 dietary vitamin B₆?P<0.05?,resspectively.WGR,hepatic vitamin B₆concentrations,AST and ALT were activities analyzed by quadratic regression.Results indicated that the dietary vitamin B₆ requirement were 8.84⁹.28 mg/kg of the diet of golden pompano.Intestinal Na+,K+-ATPase,?-glutamyl transpeptidase and creatine kinase activities increased with dietary vitamin B₆ levels up to 7.47mg·kg^-1 of the diet?P<0.05?.Chymotrypsin were statistically significant at 3.75mg·kg^-1 of the diet?P<0.05?.Tenericutes,Proteobacteria Firmicutes and Bacteroidetes were dominant in the intestines of golden pompano regardless of the diet.The relative abundance of Tenericutes and Bacteroidetes decreased while Proteobacteria and Firmicutes improved with increase of dietary vitamin B₆ levels up to 7.47 mg·kg^-1.Overall,supplementation with 7.47 mg·kg^-1 dramatically altered the growth and microbiota in the guts of golden pompano,but when dietary vitamin B₆level up to 18.5 mg·kg^-1,there was a few effect.On the side,the present study first successfully characterized the intestinal bacteria diversity in the best growth group(Diet-3 7.47 mg·kg^-1)of golden pompano.3.The dietary folic acid requirement of juvenile golden pompano?Trachinotus ovatus?Seven experimental diets were formulated to contain 0.31,0.94,1.76,2.83,4.20,5.69 and 6.32 mg·kg^-1 of folic acid.Each diet was assigned to three parallels of 25fishes[initial weight was?7.77±0.10?g]which were fed twice daily for 8 weeks.The results show that juvenile golden pompano fed diets supplemented with 4.20 mg·kg^-1folic acid had significantly higher?P<0.05?weight gain rate,specific growth rate,complement 3,complement 4,hepatic antioxidant capacities and hepatic concentration of folic acid than the control group fed with 0.31 mg·kg^-1 folic acid supplement.In contrast,moderate folic acid in feed had significantlyreduced?P<0.05?feed conversion ratio,total cholesterol and triacylglycerol.Regression analysis of the weight gain rate and hepatic concentration of folic acid showed that the folic acid requirements of juvenile golden pompano were 4.53 mg·kg^-1 and 4.94 mg·kg^-1,respectively.