Seleção de fungos celulolíticos do intestino grosso de borregos e ovelhas criados em pastagens tropicais

Abstract

The ruminal environment is composed of numerous microorganisms, each of which plays a fundamental role in the use of the diets ingested by ruminants, fungi are unicellular beings that act by degrading the fibrous portions of this diet. The objective of this study was to evaluate the cellulolytic activity (CA) of aerobic mycelial fungi from the digestive tract of sheep. Thirty-eight isolates of mycelial fungi from lambs and sheep were identified and evaluated, after re-isolation, samples of these microorganisms were inoculated in medium C, containing 1% microcrystalline cellulose as the only carbon source, and incubated in an oven at 37 °C, in triplicate, for a period of three days. AC readings were performed after 24, 48 and 72 hours of incubation. Solution containing congo red was added and after 15 minutes, the plates were washed with 15 mL of 1M NaCl solution. CA indices were calculated by the ratio between the cellulose degradation halo and the colony halo. Two isolates of the genus Aspergillus and one Trichoderma sp. showed CA index greater than one, showing good growth when using this polysaccharide as a single carbon source. Future studies should assess the potential of these fungi as probiotics in ruminant feed or for industrial microbiology.