Effects of Bacillus megaterium on growth performance, serum biochemical parameters, antioxidant capacity, and immune function in suckling calves

Background - This study was conducted to investigate the effects of Bacillus megaterium on growth performance, serum biochemical parameters, antioxidant capacity, and immune function in suckling calves. Methods - In total, 20 1-day-old Holstein calves with similar body weight (BW) and good health condition were randomly assigned into two groups with ten replicates per group and one calf per replicate. The control group (CON group) was fed a basal diet, whereas the B. megaterium group (BM group) was fed the basal diet supplemented with 500mg/day/head of B. megaterium (10(10) CFU/g) for 28 days. Results - The results revealed that the BM group showed an increase in final BW, daily weight gain, and feed-to-gain ratio (p < 0.05) and a decrease in diarrhea rate. Moreover, the concentrations of serum cholesterol and high-density lipoprotein decreased (p < 0.05) in the BM group compared with the CON group at 28 days. The level of serum glutathione was higher (p < 0.05) in the BM group than that of the CON group at 14 days, whereas the level of serum malondialdehyde decreased (p < 0.01) in the BM group compared with the CON group at 28 days. In addition, compared with the CON group (p < 0.05), the concentrations of serum IgA, IgM, IgG, and IL-4 were higher, whereas the concentration of serum TNF-alpha decreased in the BM group at 28 days. Conclusion - B. megaterium had beneficial effects on the improvement of growth performance, immune function, and intestinal oxidative status of suckling calves.