Effect of Bacillus cereus var. Toyoi and Saccharomyces boulardii on the immune response of sheep to vaccines

In this study we evaluated the effects of Bacillus cereus var. Toyoi and Saccharomyces boulardii on the immune response of lambs to Escherichia coli K88ab and Bovine Herpes Virus type 5 (BoHV-5) vaccines. Thirty, 3-month-old lambs were randomly grouped in three lots of 10 each and vaccinated at days 0 and 30 of the experiment. They grazed on the same pasture and were fed ad libitum twice a day with commercial sheep feed supplemented with either B. cereus var. Toyoi at a concentration of 1×106 viable spores gr-1, S. boulardii at a concentration of 1×106 CFU gr-1, or non-supplemented feed. Blood samples were collected at weekly intervals over eight weeks and antibody titres were analysed by ELISA. The mean seroconversions against E. coli and BoHV-5 of the fed probiotics groups were higher (p<0.001) than the controls. Both probiotics enhanced the humoral immune response of lambs to the vaccines.