Effects Of Avi Plus~?,a Blend Of Organic Acids Organic Acids And Essential Oils,on Growth,Gut Microbiota,immune Response And Disease Resistance Of Pacific White Shrimp(Litopenaeus Vannamei)

1.Effect of AviPlus~?(AP)supplementation in fish meal based diets on growth performance,gut microbiota,immune response and disease resistance of Litopenaeus vannamei against Vibrio parahaemolyticusA basal experimental diet was formulated using fish meal and soybean meal as protein sources and supplemented with 0,0.3,0.6,0.9 and 1.2 g/kg AP to produce five test diets(Con,AP0.3,AP0.6,AP0.9 and AP1.2).Each diet was fed to triplicate groups of shrimp(0.2±0.01 g,mean±SE)to apparent satiation three times daily for 8 weeks.Growth performance and survival rate were not significantly influenced by AP supplementation(P>0.05).Significantly higher serum total protein was found in groups fed?0.6 g/kg AP compared to Con group(P<0.05).Serum alkaline phosphatase and phenoloxidase activities were significantly increased in AP0.9 and AP1.2 groups(P<0.05).Also,the group received AP0.6 diet showed significantly higher glutathione peroxidase activity than group(P<0.05).Expression of gut pro-inflammatory genes including TNF-?,LITAF and Rab6a were down-regulated by AP administration.Gut microbiota analysis showed the significant enhancement of the operational taxonomic unit(OTU)richness indices by AP application(P<0.05).AP supplementation led to increased abundance of Firmicutes and a reduction in abundance of Proteobacteria.Also,dietary inclusion of 1.2 g/kg AP led to a significant increase in the abundance of Lactobacillus in shrimp gut(P<0.05).The group offered AP0.3 diet showed significantly higher disease resistance than control group(P<0.05).Furthermore,AP application significantly enhanced relative expression of immune related genes including lysozyme,penaeidin and catalase at 48 h post challenge(P<0.05).In conclusion,these findings show that the tested organic acids and essential oils mixture beneficially affects intestinal microflora and improves immune response and disease resistance of L.vannamei.2.Effect of AP supplementation in high soybean meal diets on growth performance,and Non-specific immunity in Litopenaeus vannamei fed diets with low fish mealIn this experiment five isonitrogenous(400 g/kg crude protein)and isolipidic(82.4 g/kg crude lipid)diets were formulated.A basal diet containing 25%fish meal(FM)was formulated and used as a high fish meal(HFM)diet,then four other diet were prepared by reducing FM content to 20 or 15%with or without AP supplementation referred to as SM1(20%fish meal),ASM1(20%Fish meal+0.6 g/kg AP),SM2(15%fish meal)and ASM2(15%Fish meal+0.6g/kg AP),respectively.Each diet was fed to quadruplicate groups of shrimp(0.56±0.01 g)to apparent satiation three times daily for 8 weeks.During the feeding period,survival rate ranged from 88.5%to 92.5%and did not significantly influenced(P>0.05)by dietary treatments.Weight gain(WG)in HFM and ASM1 groups were significantly higher than that of other groups(P<0.05).No significant difference in WG was observed between shrimps fed SM1 and ASM2diets(P>0.05).The shrimp fed the HFM,SM1 and ASM1 diets had lower feed conversion rate than those fed the SM2 and ASM2 diets.Apparent digestibility coefficient of protein was significantly higher in ASM1 group than SM1,SM2 and ASM2 groups(P<0.05).Serum total protein content in HFM group decreased significantly compared to SM1,ASM1 and ASM2groups(P<0.05).Serum albumin and total cholesterol contents in SM2 group were significant lower than those of HFM group(P<0.05).Serum glucose concentration in HFM group was significantly lower than that of the SM1,SM2 and ASM2 groups(P<0.05).Serum triglyceride content in SM2 group was significantly lower than that of ASM1 group(P<0.05).The activity of serum glutamic-pyruvic transaminase in HFM group was significantly lower than those of SM2and ASM2 group.Also,HFM group showed the lowest activity of serum glutamic-oxalacetic transaminase(P<0.05).The activity of serum phenoloxidase in SM1 and ASM1 group were significantly higher than those of HFM and SM2 group(P<0.05).There were no significant differences in the activity of serum superoxide dismutase(P>0.05).Serum malondialdehyde concentration in SM2 group was significantly higher than that of HFM,SM1 and ASM1 groups(P<0.05).Serum glutathion peroxidase activity and total antioxidant capacity in ASM1 and ASM2 groups were significantly higher than those of SM1 and SM2 groups(P<0.05).Shrimp hepatopancreatic in ASM1 and ASM2 group had higher R-cells than in the other groups.More hepatopancreatic damage was observed in shrimp fed SM2 diet.There were no significant differences in the mRNA relative expression of catalase,penaeidin-3a and alkaline phosphatase(P>0.05)in liver.Relative expression of hepatopancreatic lysozyme in HFM group was significantly higher than those of SM2 and ASM2 groups(P<0.05).Relative expression of hepatopancreatic C-type lectin 3 in HFM group was significantly higher than those of SM1,SM2and ASM2 group(P<0.05).Lower abundance of Pseudoalteromonas and higher OTUs were found in ASM1 and ASM2 groups compared to SM1 and SM2 groups.In intestine,the expression of tumor necrosis factor-?in ASM1 group was significantly lower than that of SM1and SM2 groups(P<0.05).Expression of NOS in SM2 group was significantly higher than the other groups(P<0.05).Expression of Rab6A in ASM1 group was significantly lower than those of HFM and SM1 groups(P<0.05).Higher expression of lysozyme was found in HFM and ASM1 groups compared to the other groups(P<0.05).There were no significant differences in the expression of intestinal superoxide dismutase(P>0.05).These findings indicated that the harmful effects of partial replacement of fish meal by soybean meal could be mitigated by supplementation of 0.6 g/kg AP diet.