Yeasts isolates from bovine rumen can improve the in vitro digestibility of Urochloa decumbens.

Commercial yeast has been frequently employed to improve the digestibility of ruminant diets, albeit these microorganisms are not indigenous to the rumen microbiome. In this investigation, our aim was to assess the in vitro digestibility of Urochloa decumbens hay (UDH) with the incorporation of two selected yeast strains isolated of ruminal fluid of Zebu cattle. Rumen fluid was collected at the onset, midpoint, and final of the dry period in a semiarid region Brazil. UDH samples were obtained from the same region. Within simulated ruminal chambers, we included McDougall buffer solution, ruminal fluid, Ankon F-57 bags containing UDH samples. Sabouraud broth (control), V62 yeast (Pichia kudriavzevii), V5 yeast (Rhodotorula mucilaginosa), or a combination thereof (mixture) were evaluated as inoculant to the ruminal fluid. The incorporation of V5, the combination of both isolates, and V5 alone resulted in significantly elevated in vitro dry matter digestibility of UDH for ruminal fluid collected at the initial, intermediate, and final stages of the dry season, respectively. Moreover, the yeast isolates demonstrated resilience to the in vitro acid digestion process, indicating their potential utility in the formulation of probiotics or microbial supplements for ruminants raised in tropical pastures during dry season.