Avaliação da estabilidade ruminal de diferentes produtos de Betaglucana extraídos de Saccharomyces cerevisiae para subsidiar seu uso como imunofármaco

Abstract

The inappropriate use of antibiotics, both in humans and animals, is primarily responsible for the selection of multidrug-resistant pathogenic bacteria. In cattle, one of the most promising recent alternatives to the classic treatment with antibiotics is the use of immunomodulators, in order to improve the host's immune defenses against pathogens, in order to promote the reduction of the use of antibiotics. Betaglucans are biopolymers with immunomodulatory activity in higher animals and are therefore classified as immunopharmaceuticals. It can be considered that betaglucans extracted from Saccharomyces cerevisiae have high activity on the immune system because they present, which favors their binding to immune system cell receptors. In the scientific literature, the immunopharmacological effect of betaglucan for monogastric animals is well established, which does not occur for ruminants. In part, this is due to antagonistic scientific results, in which some identify positive effects of the biopolymer on the immune system, while others do not identify significant biological activity. Considering both these differences in biological response and the anatomophysiological peculiarities of the digestive system of these two groups of animals, it was hypothesized that betaglucan may undergo some biotransformation in the bovine rumen after oral administration. This could impact the drug's bioavailability to the posterior segments of the digestive system. Given the above, the present project aims to evaluate the ruminal stability of four betaglucan products extracted from the same strain of S. cerevisiae, with variations in the culture medium and in the extraction process. Samples were incubated in the rumen of fistulated cattle (in situ) for 72 hours. The analysis times were 6, 12, 24, 48 and 72 h. For these samples, mass loss and chemical modifications of the polymeric chain were evaluated by Raman spectroscopy, infrared spectroscopy and NMR techniques. The rate of mass loss varied in all betaglucan extracts, probably after cleavage of the polymeric chain at the β(1,3) and β(1,6) bonds. With loss of molecular weight and intensity of polymer chain branching. The passage of betaglucan through the rumen promoted chemical modifications in different betaglucan extracts. Such a condition has the potential to impact both the bioavailability and the biological activity of orally administered beta-glucan for cattle.