Efeito de Saccharomyces boulardii e Bacillus cereus var. toyoi na resposta imune de cordeiros vacinados contra Escherichia coli e Herpes vírus bovino-5

Abstract

Probiotics are products that contain viable microorganisms that modulate mucosal microbiota with beneficial effects on health. They are useful in the prevention and treatment of diseases, inhibit carcinogenesis, increase feed efficiency being an alternative to antibiotics, and modulate immune responses. Most of the reports on the effects of probiotics on the immune response were produced using lactobacillaceae or bifidobacteria, and although the processes involved are not completely understood, there is no doubt about heir beneficial effect on humoral and cellular responses. More potent vaccines that produce less undesirable effects were developed using efficient adjuvants and purified antigens. Probiotics can potentiate the response to vaccines, opening a new perspective for their use. The objective of this work was to evaluate the effect of two probiotics, one prepared with Bacillus cereus var. toyoi and the other with Saccharomyces boulardii, on the immune response of lambs vaccinated against Escherichia coli and Bovine Herpesvirus-5. Thirty three-month old lambs were vaccinated with one dose of each vaccine on days 0 and 30 of the experiment, and randomly divided in three groups of 10 each. The animals were maintained in the same pasture and supplemented with the respective feed ad libitum. Feed of group 1 contained Bacillus cereus var. toyoi at a concentration of 1x106 viable spores gr-1, and that of group 2, 1x106 CFU gr-1 of Saccharomyces boulardii, while group 3 received non-supplemented feed. Blood samples were obtained at weekly intervals for eight weeks. Antibody titres were determined by ELISA using vaccinal strains as antigens. Individual absorbancies and means for each group were divided by those at day 0 and expressed as seroconversions. The higher seroconversions against the E. coli bacterin were 1.3, 1.9 and 0.9 for the B. cereus var. toyoi, S. boulardii and control groups, respectively, all different among them (p<0,05). The higher seroconversions against the BoHV-5 vaccine were 2.7, 1.7 and 1.3 for the B. cereus var. toyoi, S. boulardii and control groups, respectively, all different among them (p<0,05). The results showed that S. boulardii induced higher soroconversions against E. coli and that B. cereus var. toyoi higher soroconversions against BoHV-5.