| Litopenaeus vannamei is one of the most productive shrimp species in the world.It has the advantages of short growth cycle,strong fecundity,high survival rate,strong environmental stress resistance and easy transportation of live shrimp.It has produced great economic and social benefits.However,the diseases of prawn can not be ignored,such as acute hepatopancreatic necrosis of prawn caused by Vibrio parahaemolyticus(Vp AHPND),white spot syndrome virus(WSSV),infectious subcutaneous and hematopoietic necrosis virus(IHHNV),white stool disease,enterocystis hepatica(EHP),early death syndrome(EMS)and so on,and has caused great economic losses to shrimp farming.Therefore,the development of green and high-efficiency drugs has become a hot and difficult point in disease control of L vannamei.In the present study,compound Chinese herbal medicine(CCHM)was fed to shrimps to explore its effect on the growth performance,digestive enzyme activity,immunity and metabolism and Vibrio parahaemolyticus resistance of L vannamei.The main findings are as follows:1.Effects of CCHM on growth performance,digestive enzyme activity,related gene expression and antimicrobial activity of L.vannameiThe 30-day feeding trial of shrimp(4.66±0.33 g)showed that CCHM significantly increased the survival rate(SR),weight gain rate(WGR)and specific growth rate(SGR)of shrimp,and significantly decreased the feed conversion rate(FCR).The activities of protease,amylase and lipase in stomach,hepatopancreas and intestine were significantly increased by 1.0% CCHM(P<0.05),and the number of haemocytes was significantly increased by 1.0% and 1.5% CHMM(P<0.05).The activities of total superoxide dismutase(T-SOD),glutathione peroxidase(GSH-Px)and catalase(CAT)in hepatopancreas of 1.0%CCHM group were significantly higher than those of control group(P<0.05).The gene expression levels of SOD,CAT,ATPase,trypsin,chymotrypsin and GS in hepatopancreas and intestines of shrimp fed with 1.0% CCHM were significantly up-regulated(P<0.05),and the relative protection rate against Vibrio parahaemolyticus in CCHM groups was significantly increased(P<0.05).2.Effects of CCHM against antibiotic resistance V.parahaemolyticus of L.vannameiAfter 28 days of feeding with CCHM diet,the shrimp(5.39±0.56 g)was infected with V.parahaemolyticus for 6 days,and the growth performance,digestive enzyme activity,anti-oxidation index and related gene expression of prawns were analyzed before,3 d and 6 d after infection with Vibrio.The results showed that the WGR and SGR of shrimp in 1.0% CCHM and 1.5% CCHM groups were significantly increased(P<0.05).On the 3rd and 6th day of Vibrio infection,the cumulative mortality of shrimp in CCHM groups was significantly lower than that in control group(P<0.05).The lymphocytes of prawns in CCHM groups was significantly higher than that in control group before and after Vibrio infection(P<0.05).The activities of protease,amylase and lipase in hepatopancreas,stomachs and intestines of prawns in 1.0% CCHM group were significantly higher than those in control group after 3 days and 6 days(P<0.05).Before and after Vibrio infection,the activities of alkaline phosphatase(AKP),CAT,ATPase and SOD in CCHM groups were significantly higher than those in control group(P<0.05),and.the activities of aspartate aminotransferase(GOT)and alanine aminotransferase(GPT)in1.0% CCHM group were significantly higher than those in control group(P<0.05),and the content of malondialdehyde(MDA)in 0.5% CCHM and 1.0% CCHM groups was significantly lower than that of control group(P<0.05).The AKP activity in haemolymph of CCHM group was significantly higher than that of control group on the 3rd and 6th day after infection(P<0.05).Before and after Vibrio infection,the activity of phenoloxidase(PO)in haemolymph of CCHM group was significantly higher than that of control group(P<0.05),and the activity of GOT and GPT in haemolymph of CCHM group was significantly lower than that of control group(P<0.05).The gene expression of trypsin,chymotrypsin,ATPase,SOD,glutamate dehydrogenase,antimicrobial peptide,glutathione sulfhydryltransferase,cytochrome C oxidase and hemocyanin were significantly up-regulated on the third day of infection(P<0.05).The PO gene expression in blood lymphocyte of shrimp was significantly up-regulated in 0.5% CCHM and 1.0% CCHM groups before and on the 3rd day of infection(P<0.05).Before and on the third day of infection,the expression of PO gene of shrimp lymphocytes in 0.5% CCHM and 1.0%CCHM groups was significantly up-regulated(P<0.05). |
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