| Immune enhancer,as a very popular feed additive for aquatic animals,can activate immune active cells,enhance self-immune function and activate animal immunity,and can effectively prevent and control diseases in aquaculture.It can enrich the body fatness of cultured objects and improve the quality and value of aquatic animals.Now it has been widely used in fish culture.According to the types,the commonly used immune enhancers can be divided into animal and plant immune enhancers,microbial immune enhancers,synthetic immune enhancers,nutritional factors and so on.In this paper,two representative immune enhancers were selected from the market in order to study the addition of two kinds of aquatic immune enhancers to feed.The main active components of immunoenhancer A are mannose oligosaccharide,carrier glucose,starch and so on.The effective components of immune enhancer B are mainly amino acids,growthpromoting factors,active yeast polysaccharide peptides,food attractants,living bacteria probiotics and so on.The purpose of this study was to investigate the effects of two kinds of aquatic immune enhancers on serum biochemical indexes,tissue immunity-related cytokines and other non-specific immune indexes of crucian carp.Immunopotentiator A and immunopotentiator B were added to the basic diet of crucian carp according to 0.6%,respectively.Samples were taken for 21 days for 14 days and 28 days for 35 days,respectively.ELISA method was used to detect some related immune enzymes in crucian carp serum: immunoglobulin M(Ig M),complement C3,C4,acid phosphatase(AKP),lysozyme(LZM),alkaline phosphatase(ACP).Antioxidant indexes: the contents of superoxide dismutase(SOD),catalase(CAT)and glutamic oxaloacetic transaminase(AST)were used to determine the effects of two immune enhancers on serum biochemical indexes of crucian carp.The results showed that group A(0.6% immune enhancer A + basic feed)and group B(0.6% immune enhancer B + basic feed)on the 35 th day,the related immune enzymes such as ACP,AKP,LZM and C4 in crucian carp serum were significantly higher than those in the control group(p < 0.001).The content of Ig M in group A was significantly higher than that in the control group(p < 0.001).Compared with the control group,the improvement in group B was not significant(p > 0.05).The content of C3 in serum of group B was significantly higher than that of the control group(p < 0.001),while that of group A was not significantly higher than that of the control group(p > 0.05).The content of C3 in serum of group A and group B increased significantly(p < 0.05),which increased by 73.6% and 50.1%.The relative expression of immune cytokines such as interleukin-10(IL-10),interleukin-1(IL-1-β),transforming growth factor-β(TGF--β)and tumor necrosis factor-α(TNF-α)in crucian carp tissue was determined by fluorescence quantitative PCR method.The results showed that all the indexes were improved after feeding two kinds of crucian carp immune enhancers.Crucian carp fed with two kinds of immune enhancers for 35 days were challenged with 1×108CFU/ml Aeromonas hydrophila BSK-10(Aeromonashydrophila,Ah).The death records of crucian carp were recorded by II to determine the effects of two immune enhancers on the death of crucian carp.The results showed that 10 days after challenge,all the crucian carps in the control group died,and the survival rate of crucian carp in group A was 42.86%.The survival rate of crucian carp in group B was 51.43%.The results showed that the two immune enhancers could significantly enhance the immune function and hydrophilicity of crucian carp. |
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