Effects of Dietary Supplementation of Clostridium butyricum or Sodium Butyrate on Growth Performance,Serum Biochemical Indexes,Liver Immune and Antioxidant Capacity of Largemouth Bass
The aim of this experiment was to investigate the effects of adding Clostridium butyricum(CB)or sodium butyrate(SB)to the diet on growth performance,serum biochemical indexes,liver immunity,antioxi-dant capacity and hypoxia stress of juvenile largemouth bass(Micropterus salmoides).Three kinds of iso-nitro-gen(50%)and iso-lipid(9%)diets were prepared,which were the basal diet(Con),the basal diet supple-mented with 10 mL/kg CB,and the basal diet supplemented with 1.0 g/kg SB.A total of 360 fish with body weight of(5.02±0.01)g were randomly divided into 3 groups and fed 3 kinds of diets with 3 replicates per group and 40 fish per replicate.The culture experiment was carried out for 8 weeks,and then hypoxia stress test was carried out.The results showed as follows:1)compared with Con group,weight gain rate(WGR)and protein deposition rate(PDR)in CB group were significantly increased(P<0.05),and feed conversion ratio(FCR)in CB group was significantly decreased(P<0.05).Compared with Con group,the intestinal body index(ISI)in CB group was significantly increased(P<0.05).2)Compared with Con group,the ser-um alkaline phosphatase(AKP)activity and triglyceride(TG)content in SB group were significantly de-creased(P<0.05),the serum urea nitrogen content in CB and SB groups was significantly decreased(P<0.05),and the serum glucose(GLU)content in SB group was significantly increased(P<0.05).3)Com-pared with Con group,dietary CB and SB supplementation significantly increased liver total protein(TP)con-tent(P<0.05),and liver catalase(CAT),superoxide dismutase(SOD)and lysozyme(LZM)activities in CB and SB groups were significantly increased(P<0.05).The liver malondialdehyde(MDA)content in SB group was significantly lower than that in Con group(P<0.05).4)Compared with Con group,the relative expression level of Toll-like receptor 22(TLR22)gene in liver of SB group was significantly increased(P<0.05).The relative expression levels of interleukin-1β(IL-1β),interleukin-8(IL-8)and myeloid differentia-tion factor 88(MyD88)genes in CB and SB groups were significantly decreased(P<0.05),and the relative expression levels of insulin-like growth factor-1(IGF-1)and growth hormone(GH)genes in CB group were significantly increased(P<0.05).5)After 3 h of hypoxia stress,the cumulative mortality of Con,CB and SB groups was 68.75%,31.25%and 35.42%,respectively.Compared with Con group,the cumulative mortality in CB group and SB group was significantly decreased(P<0.05).In conclusion,dietary supplementation of CB and SB can improve the growth performance,liver antioxidant enzyme activity,inhibit the expression of liver anti-inflammatory factors of largemouth bass,and improve the survival rate under hypoxia stress.Com-pared with SB,CB supplementation has better effects on growth performance,immunity and antioxidant of largemouth bass.[Chinese Journal of Animal Nutrition,2024,36(4):2572-2585]