| Flammulina velutipes stembase polysaccharides were prepared by different concentration of ethanol,protein removal and column chromatography.The effects of ethanol concentration during fractionation and the degree of purification on the in vitro antioxidant properties of Flammulina velutipes stembase polysaccharides were analyzed.Meanwhile,the effects of Flammulina velutipes stembase on antioxidant properties in vitro,growth,immunity and intestinal flora of juvenile brook trout(Salvelinus fontinalis)were studied.270 juvenile brook trout were randomly divided into three groups(CK: control group;FVS: 2% Flammulina velutipes stembase powder supplementation group;FVSE: 2% Flammulina velutipes stembase extract supplementation group),each group had three replications.The experiment lasted for 81 d.The results showed that:1.During the extraction of polysaccharides from Flammulina velutipes stembase,the ethanol concentration during isolation had an impact on the antioxidant activity of the FVSPs.In the trial range,when the ethanol concentration was low,the antioxidant activity was weak.As the ethanol concentration increased,the antioxidant activity gradually increased.The degree of purification also influenced the antioxidant activity of the FVSPs: In the trial range,the degree of purification was low,the antioxidant activity was high.2.The addition of Flammulina velutipes stembase could significantly improve the antioxidant capacity and the growth performance of Salvelinus fontinalis,but have no effect on the nutritional components.The total antioxidant capacity(T-AOC),superoxide dismutase(SOD)and catalase(CAT)activity in the hepatopancreas were significantly increased in group FVS and group FVSE(P?0.05),and the activity of catalase(CAT)in FVSE group was significantly higher than that in FVS group(P?0.05).The final body weight(FBW),weight gain(WG),specific growth rate(SGR)and survival rate(SR)in group FVS and group FVSE were significantly higher than that of the control group(P?0.05);the feed conversion rate(FCR)in group FVS and FVSE group was significantly lower than that of the control group(P?0.05);the hepatosomatic index(HIS)in the FVSE group was significantly higher than that of the control group(P?0.05);The effects on moisture,crude protein,crude fat and ash content of the whole fish were not significant(P?0.05).3.The addition of Flammulina velutipes stembase could affect the serum indices,significantly improve the nonspecific immunity,reduce the expression of heat shock protein HSP70 and HSP90 mRNA,improve the tolerance to the adverse environment.Serum total protein(TP)content and aspartate transaminase(AST)activity in FVS group were significantly higher than those in control group(P?0.05),and alanine transaminase(ALT)activity was significantly lower than that in control group(P?0.05).The activity of total protein(TP),albumin(ALB),globulin(GLO),glucose(GLU),total cholesterol(CHOL)and aspartate e transaminase(AST)activity in the serum of FVSE group was significantly increased(P?0.05),and the activity of alanine transaminase(ALT)was significantly reduced(P?0.05).The content of total protein(TP)in serum of group FVSE was significantly higher than that of group FVS(P?0.05).In group FVS,the activity of alkaline phosphatase(AKP)and acid phosphatase(ACP)in the hepatopancreas increased significantly(P?0.05),and the activity of lysozyme(LYZ),alkaline phosphatase(AKP)and acid phosphatase(ACP)in group FVSE increased significantly(P?0.05).In group FVSE,the activity of acid phosphatase(ACP)was significantly higher than that of group FVS(P?0.05).Both group FVS and group FVSE reduced significantly the expression of HSP70 and HSP90 mRNA in hepatopancreas(P?0.05).4.The core flora of Salvelinus fontinalis mainly includes Proteobacteria,Actinobacteria and Firmicutes,and Proteobacteria is the highest.The addition of Flammulina velutipes stembase could increase the diversity and abundance of intestinal flora,and the diversity and abundance of the flora in FVS group were significantly increased(P?0.05),while the abundance of the flora in FVSE group was significantly increased(P?0.05).Proteobacteria decreased significantly in FVS group(P?0.05),while Actinobacteria,Cyanobacteria,Chloroflexi,Verrucomicrobia,Saccharibacteria and Chlamydiae increased significantly(P?0.05).Only Chlamydiae increased significantly in FVSE group(P?0.05).In conclusion,the antioxidant activity of polysaccharides from Flammulina velutipes stembase in vitro is related to ethanol concentration during isolation and purity.The antioxidant activity of polysaccharides from Flammulina velutipes stembase is strong when the ethanol concentration was high during isolation or the degree of purification is lower.The polysaccharides from Flammulina velutipes stembase can also play an antioxidant role in Salvelinus fontinalis,improve antioxidant status,improve growth performance and immunity,and regulate intestinal flora composition. |
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