Beta-glucano purificado como modulador da resposta imune em cães adultos

Abstract

The increased demand for functional foods in companion animal nutrition has driven the use of bioactive compounds with immunomodulatory effects, such as beta-glucans. These polysaccharides, mainly extracted from the cell wall of the yeast Saccharomyces cerevisiae, are recognized for their ability to modulate immune responses, promote metabolic benefits, and contribute to the health and well-being of animals. The present study aimed to evaluate the effects of dietary supplementation with purified beta-glucans on the immune response of adult dogs subjected to a vaccination challenge. 14 clinically healthy Beagle dogs were randomly assigned to three experimental groups: control (no supplementation) and one group supplemented with a commercial source of beta-glucans at a dose of 1%. The animals were fed isonutritive diets for 42 days and, on day 21, were orally vaccinated against Bordetella bronchiseptica to evaluate the immune response to the challenge. Hematological, biochemical, and immunological analyses were performed on days 1, 7, and 21 post-vaccination. Apparent nutrient digestibility and fecal scores were also assessed. The results indicated that supplementation did not cause significant changes in most hematological parameters, except for a significant interaction between diet and time for segmented neutrophils, suggesting modulation of innate immunity. IgA showed a significant increase over time and a trend toward interaction with diet, indicating a possible enhancement of mucosal immunity. Lipid biochemical parameters did not exhibit marked changes, although a trend toward increased total cholesterol and preservation of HDL was observed in the supplemented group. Supplementation did not significantly alter cortisol levels, indicating no effect on the response to vaccination-induced stress. Regarding digestibility, beta-glucans did not impair the absorption of dry matter, protein, and fat but promoted a significant increase in mineral digestibility, suggesting benefits in micronutrient absorption. In summary, supplementation with beta-glucans proved safe and demonstrated targeted immunomodulatory potential, especially for innate immunity and mineral digestibility, in vaccinated adult dogs.