Cinética da fermentação in vitro de alimentos com inóculo ruminal de bovinos de corte em pastejo recebendo diferentes tipos de suplemento

Abstract

The objective was to evaluate the effect of different types of supplement, during the dry-water transition period and in the rainy season, in order to estimate the kinetics of the in vitro fermentation of Brachiaria brizantha cv. Marandu, ground corn and soybean meal.The experiment was carried out in a double 4x4 Latin square, using eight Nellore steers fistulated in the rumenas rumen fluid donors that received different types of supplements: mineral supplementation, protein supplementation, energy supplementation and protein-energy supplementation. In vitro incubation techniques were implemented for the evaluations of accumulated gas production, kinetic parameters, and ruminal fermentation profile. In the dry-water transition period the volume of gas generated by the degradation of fibrous carbohydrates was superior to soybean meal (P<0.001) in inoculum whose diet included concentrated food. The ground corn ingredient (P=0.03) presented a higher degradation rate of non-fibrous carbohydrates in the ruminal inoculum from cattle supplemented with protein, energy, and protein-energy in comparison with the mineral supplementation. Marandugrass (P=0.008) and ground corn (P=0.02) showed higher partitioning factor values in the inoculum from animals whose diet included the concentrate during the dry-water

transition period. In the rainy season, for marandugrass, ruminal inoculum of protein- supplemented cattle provided higher dry matter degradability than the ruminal

inoculum of cattle that received protein-energy (P=0.004) and energy (P=0.029) supplementation. The inclusion of the dietary concentrate provided greater metabolizable energy in marandugrass (P=0.026) and soybean meal (P=0.043) during the rainy season. Ruminal inoculum of cattle receiving different types of supplement influence the cumulative gas production, and the inclusion of the concentrate in the diet benefits the ruminal fermentation profile of marandugrass, ground corn, and soybean meal in the period of dry-water transition and in the rainy season. During the period of dry-water transition, ruminal inoculum from bovines subjected to different

diets did not affect the volume of gas and the rate of slow degradation of ground corn. In the rainy season, ruminal inoculum subjected to different diets influence the degradation rates of ground corn and soybean meal, but do not alter the kinetic parameters of in vitro fermentation of marandugrass.