Effect of supplementing with with different doses probiotics on fiber digestibility and rumen ecosystem of growing cattle receiving two levels of concentrate

Abstract

The lower fiber digestibility in tropical pastures, is the main obstacle to increasing animal performance in these systems. The use of concentrated supplements for grazing animals during the rainy season, make up the deficiencies in the quality of forage by optimizing the average daily gain. Different doses of Saccharomyces cerevisiae, has been fed to ruminants, and can cause beneficial effects on the digestive tract of the animal, such as increased fiber digestibility. The objective of the study is to evaluate the effect of supplementation with different strains of S. cerevisiae on fiber digestibility, dry matter intake and rumen kinetics of Nellore cattle fed hay, receiving or not, energy supplementation, using the following parameters: 1) Consumption of dry matter; 2) ruminal fermentation parameters; and 3) measurement of ruminal microorganisms. A total of 36 animals, fistulated in the rumen, with approximately 24 months of age and 400 kg will be kept in individual stalls, where they will receive daily doses of yeast. The experimental design is a randomized block with six replications per treatment, in a factorial arrangement 3x2 (control, supplemented with S. cerevisiae dose I and the group supplemented with S. cerevisiae dose V and groups with or without energy supplementation). Rumen fluid will be collected for measurement of pH, SCFA and ammonia. In determining the volume, total weight and size of the rumen compartment will be completely evacuated. Samples of the liquid and solid phases will be taken for chemical analysis to determine the digesta components and population of rumen microbes by PCR in real time. This study will enable the identification and assessment of the effects of different doses of S. cerevisiae on ruminal metabolism and digestibility of fiber, allowing better understanding of the mechanisms of action of these yeasts in the feeding of beef cattle grazing, at different levels of supplementation. (AU)