Abstract:
【Objective】This experiment was performed to investigate the effects of dietary
Clostridium butyricum on growth performance, digestion, immunity, antioxidant capacity and intestinal microbiota of juvenile
Lateolabrax maculatus, and provide a theoretical basis for the application of C.butyricum in the culture of L.maculatus. 【Method】Juvenile L.maculatus was used as experiment material. Juvenile L. maculatus had been fed for 56 d with six diets containing 0(D0, control), 0.25%(D1), 0.50%(D2), 1.00%(D3), 2.00%(D4) and 4.00%(D5) C. butyricum. The growth performance, intestinal digestive enzyme activity, serum biochemical and immune indicators, and intestinal morphology indicators of juvenile L.maculatus were measured, and the composition of intestinal microbiota was analyzed. 【Result】The dietary C.butyricum could significantly reduce the feed coefficient(
P<0.05,the same below), significantly improved final mean body weight of L. maculates, the weight gain rate(WGR), and specific growth rate(SGR) in D3, D4 and D5 groups were significantly higher than the D0 group. Compared with D0 group, the activities of intestinal chymotrypsin, lipase were significantly increased in D4 group, while the contents of serum total cholesterol and triglyceride and the activities of glutamic oxalacetic transaminase and glutamicpyruvic transaminase were significantly decreased. The activities of lysozyme, alkaline phosphatase and total nitric oxide synthase in D4 group were significantly higher than those in D0group, and the activities of phenoloxidase in D3 group were significantly higher than those in D0 group. Compared with D0 group, the catalase activity and total antioxidant capacity in D3 and D5 groups were significantly increased, the superoxide dismutase activity in D4 group was significantly increased, and the malondialdehyde content was significantly decreased. The intestinal muscle thickness and villus height in D2, D3 and D5 groups were significantly higher than those in D0 group. The OTU number and Chao1 index of the intestinal microflora of juvenile L.maculatus in D3 group were significantly higher than those in D0 group, and the Simpson index and Shannon index of the intestinal microflora in all test groups were significantly higher than those in D0 group. At the phylum level, C. butyricum reduced the relative abundance of Proteobacteria and Firmicutes. The relative abundance of Actinobacteriota, Planctomycetota, Acidobacteriota, Chloroflexi, Bacteroidota and Gemmatimonadota increased. At the genus level, C. butyricum decreased the relative abundance of harmful bacteria like Ralstonia, Enterovibrio and Vibrio, and increased the relative abundance of beneficial bacteria like Arthrobacter and
KD4-96_unclassified. 【Conclusion】Adding C. butyricum in the dietary can significantly improve the growth performance, improve the digestion, immunity and antioxidant capacity of juvenile L.maculatus, regulate the structure and relative abundance and improve the diversity of intestinal microbiota of juvenile L. maculatus.The best effect is to add 2.00% of C.butyricum to the dietary.