Avaliação do efeito imunomodulador de Bacillus toyonensis em cães vacinados contra Parvovírus

Abstract

Probiotics are live microorganisms that when administered in adequate quantities promote health benefits to the host. The mechanisms of action of probiotics include factors that enhance the body's natural defenses, among which it is possible to cite the modulation of the immune response. Bacillus toyonensis is a probiotic microorganism that for decades has been used in animal nutrition around the world. The objective of this work was to evaluate the immunomodulatory effect of probiotic B. toyonensis supplementation for dogs that were vaccinated against parvovirus. 10 Australian Cattle Dog dogs from two litters with 45 days were randoy selected to form two groups, where one group received oral B. toyonensis at a concentration of 2x108 viable spores per day for 35 days and for the other group only phosphate saline was administered. Dogs were vaccinated against canine parvovirus type 2 on day 7 and 28 of the experiment, and blood samples were collected on days 0, 7, 21 and 35 of the experiment. Total antigen-specific IgG antibody levels were determined by indirect ELISA. B. toyonensis supplementation was efficient in stimulating the production of higher antibody titers 4 times higher (p <0.05) when compared to control animals on all days analyzed. The hemograms showed an expected hematological profile for the species and age of the animals. Peripheral blood mononuclear cells (PBMCs) from dogs were cultured and stimulated with DNA, vegetative cell and B. toyonensis spores. By qPCR the mRNA transcription of cytokines IL-4, IL-17, and IFN-γ in PBMCs was evaluated. B. toyonensis spores induced IL-4 (4.4-fold), IL-17 (1.3-fold) and IFN-γ (1.6-fold) mRNA transcription, the DNA obtained IL-4 (4.7 fold), IL-17 (3.5-fold), and IFN-γ (2-fold), and the vegetative cells were responsible for inducing IL-4 (1.7-fold), IL- IFN-γ (1.2 fold).Thus, we conclude in this study that B. toyonensis supplementation may amplify the vaccine immune response against parvovirus in dogs.