Relação entre a microbiota do Rúmen e o aumento no ganho de peso em bovinos de corte

Abstract

Bovines (Bos taurus) are animals with great economic importance, especially in the production of meat and milk, moving billions of dollars every year. They are very widespread in Brazil, especially in the Pampa, since the Great Navigations period when they were brought by European colonists. These animals are classified as ruminants due they have a multi-cavity stomach where the first portion is called rumen. In this environment, microorganisms such as bacteria and fungi act in the degradation of ingested food and in the production of absorbable compounds by the animal throughout the gastrointestinal tract. The present work aimed to analyze the bovine rumen microbiota and its relationship with animal nutrition. Rumen samples of ruminal liquid from heifers provided by the Department of Diagnosis and Agricultural Research (DDPA) were collected in the city of São Gabriel, RS. These heifers were monitored for 60 days for analysis of nutritional aspects (such as average weight gain) and, subsequently, grouped into groups related to this monitoring for comparative analyzes. The microbial DNA (ITS2 region for fungi and V4 region of 16S rRNA for bacteria) was amplified by PCR and sequenced on the Ion PGM platform. The sequences were processed according to the recommendations of the Brazilian Microbiome Project and analyzed in the R environment. With this, a pattern of microorganisms linked to animals with greater weight gain was identified, being these organisms known to produce enzymes that degrade more efficiently vegetable organic matter. The data point to a combination of fungi and bacteria that are associated with greater weight gain, including the bacterial genera RFN20, Prevotella and Anaeroplasma as well as the fungal genera Aureobasidium, Cryptococcus and Sarocladium. In higher taxa, microorganisms assigned as belonging to the family RF16 and to the orders Tremellales and Pleosporales also showed relationship with a higher gain of weight. Among archaeas, it was found only the phylum Euryarchaeota (0.2% of sequences), which did not show difference between the groups. These reports suggest that is possible the use of these microorganisms in later studies both as efficiency markers and in microbial therapies to increase weight gain.