Fungos e protozoários do trato digestório de cordeiros alimentados com feno da folha de bananeira

Abstract

The sheep husbandry is an important source of income for the rural population in the north of Minas Gerais, but the long period of drought is a limiting factor for livestock, in this context the interest of research using agro-industrial byproducts in ruminant feeding arises. We used 30 animals which were about five months old, with an average weight of 24.50 kg and created in intensive system, with adaptation of 15 days. The animals were distributed in a completely randomized design with six replications and five treatments, remaining on feedlot for three periods of 21 days. The treatments were: T1 (100% Cynodon spp. hay); T2 12.5% (banana leaf hay) + 37.5% (Cynodon spp. hay); T3 (25% banana leaf hay) + 25% (Cynodon spp. hay); T4 37.5% (banana leaf hay) + 12.5% (Cynodon spp. hay); T5 (100% banana leaf hay). Diets showed a roughage: concentrate ratio of 50:50, isoproteic. We evaluated the characteristics of the rumen fluid of sheep fed banana leaf hay. Physicochemical characteristics were immediately evaluated after collection of ruminal fluid. We performed micromorphological examination of the rumen fluid, direct examination of strict anaerobes fungi and cultivation, quantification, isolation and identification of aerobic fungi from the rumen, quantification, identification of rumen protozoa and cellulolytic activity of the rumen aerobic fungi. It was found that the concentrations of mycelial fungi in the rumen fluid of the sheep fed banana leaf hay (Musa sp.) and Cynodon sp. hay is significantly lower when compared to the concentration of yeast. Fungi from the Aspergillus genus are prevalent among isolates from the rumen and feces of sheep fed banana leaf hay (Musa sp .) and Cynodon sp. hay. Among isolates of these microorganisms, 69.44% have cellulolytic activity higher than one, which indicates good capacity for cellulose degradation and high potential for the development of probiotics or prebiotics in ruminant food. The total protozoa population and Entodinium genus are reduced in the rumen of these animals. It is suggested the inhibitory effect of condensed tannins or other compounds of that plant on ruminal mycrobiota.