Effects Of Organic Acids On Growth,Nutrient Utilization And Intestinal Microflora Of Litopenaeus Vannamei

1 Effects of Adding Organic Acid Complex in Diets on Growth,Nutrient Utilization,Serum Biochemical Indexes and Intestinal Microflora of Pacific white shrimp,Litopenaeus vannameiThis study was conducted to investigate the effects of dietary organic acid complex on growth performance,nutrient utilization,hepatopancreas enzyme activity,serum non-specific immune enzyme activity and intestinal microbial composition of Pacific white shrimp,Litopenaeus vannamei.Four isonitrogenous and isolipidic diets were made by adding 0,0.05 %,0.10 %,and 0.15 % organic acids complex(OC,fumaric acid as the major component)(OC-0,OC-5,OC-10,OC-15)to the basal diet which contained 10% fish meal.A total of 1000 shrimp(1.10 ± 0.09 g)were randomly allocated into 20 cages(5 cages per group,50 shrimp per cage)and fed with the above 4 diets for 8 weeks.Compared to the OC-0 group,the weight gain rate of OC-5 and OC-10 groups were increased by 18.7 % and 17.9 %,and the feed conversion ratio were decreased by 16.1% and 18.5 %(P < 0.05),respectively.In body composition,the addition of OC in diets reduced the crude fat significantly(P < 0.05),and the contents of OC-5 and OC-10 groups’ crude protein were significantly higher than that of OC-0 group(P < 0.05).Dietary supplementation of OC had no significant effect on nutrient digestibility,but significantly increased hepatopancreas amylase activity(P < 0.05)and serum SOD activity(P < 0.05).The analysis of intestinal microbiota showed that OC increased the abundance of intestinal flora in Litopenaeus vannamei.In summary,the addition of organic acid complex in diets can promote the growth and feed utilization of Litopenaeus vannamei,and the appropriate addition amount of OC is 0.10 %.2 Effects of Adding Sodium Butyrate and Clostridium Butyricum in Diets on Growth,Hepatopancreas Health,Serum Biochemical Parameters and Intestinal Histology and Microflora of Pacific white shrimpThis study was conducted to investigate the dietary effects of sodium butyrate and clostridium butyricum on growth performance,nutrient utilization,hepatopancreas health,serum non-specific immune enzyme activity and intestinal health of Pacific white shrimp.Five isonitrogenous and isolipidic diets(FM12,BUT-1,BUT-2,BUT-3,CBUT-2)were prepared by adding 0,0.1 %,0.2 %,0.3 % sodium butyrate and 0.2 % clostridium butyricum to the basal diet which contaied 12 % fish meal.A total of 600 shrimps(1.90 ± 0.08 g)were randomly allocated into 20 cages(5 cages per group,30 shrimps per cage)and fed with the above 5 diets for 8 weeks.Compared to the control group,the weight gain rate of BUT-1,BUT-2 and CBUT-2 groups was increased significantly,while the feed conversion ratio(FCR)was decreased significantly(P < 0.05).The addition of sodium butyrate and clostridium butyricum significantly increased crude protein content of the whole shrimp and the activities of alkaline phosphatase,lysozyme and peroxidase in serum(P < 0.05).The superoxide dismutase activity was also significantly increased by the addition of sodium butyrate(P < 0.05).BUT-2 group(0.2 % sodium butyrate)showed significantly higher hepatopancreas protease activity than the control(P < 0.05).In terms of intestinal histology and intestinal flora,the intestinal wall thickness of BUT-1,BUT-2,BUT-3,and CBUT-2 groups was significantly higher than that of the control group(P < 0.05),while the addition of sodium butyrate(BUT-2)and Clostridium butyricum(CBUT-2)did not significantly affect the richness and composition of intestinal flora(P>0.05).In summary,dietary addition of 0.2 % sodium butyrate and 0.2 % clostridium butyricum significantly increased weight gain rate,body crude protein content,and reduced FCR,but showed no significant effects on intestinal microbial composition of Pacific white shrimp.3 Comparison of the Effects of Fumaric Acid and Malic Acid on Pacific white shrimpThis study compared the effects of dietary fumaric acid and malic acid on growth performance,nutrient utilization,hepatopancreas health,serum non-specific immune enzyme activity and intestinal health of Pacific white shrimp.Three isonitrogenous and isolipidic diets were prepared by adding 0.2 % fumaric acid,malic acid(FUM,MA)to a basal diet containing 12 % fish meal(FM12).A total of 360 shrimp(1.90 ± 0.09 g)were randomly allocated into 12 cages(4 cages per group,30 shrimps per cage)and fed with the above three diets for 8 weeks.Compared to FM12 group,the weight gain rate(WGR)of FUM group was significantly increased,and feed conversion ratio(FCR)was significantly decreased(P<0.05).MA group also presented significantly lower FCR than FM12 group(P < 0.05),but WGR was not significantly different from the control group(P > 0.05).Dietary addition of organic acids showed no significant effects on the body composition of shrimp(P > 0.05).Compared to the control group,the hepatopancreas protease activity and serum alkaline phosphatase,peroxidase activityin FUM group were significantly increased(P < 0.05).In terms of intestinal morphology,the intestinal wall thickness of FUM and MA groups was increased significantly(P < 0.05).The analysis of intestinal flora showed that the Sobs index and Chao index of FUM group and MA group were significantly lower than those of the control group(P < 0.05).In summary,dietary fumaric acid(0.2%)can promote the growth of Pacific white shrimp and reduce FCR,while the addition of 0.2 % malic acid also improved feed utilization fumaric acid showed better growth-promoting effects than malic acid.