Antioxidant action in diets with ground soybeans on ruminal microbial production, digestion, and fermentation in buffaloes

ABSTRACT The objective of this study was to evaluate the effect of adding ground soybeans and antioxidants to diet of buffaloes on intake, ruminal microbial production, total and ruminal digestibility of nutrients, and ruminal fermentation parameters. Four crossbred buffaloes with a mean weight of 506±29 kg were distributed in a 4×4 Latin square. Four diets were tested: control; diet with ground soybeans; diet with ground soybeans and supplementation with yerba mate; and diet with ground soybeans and supplementation with yerba mate and vitamin E. The addition of ground soybeans had negative effects on intake of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, as well as ruminal digestibility of neutral detergent fiber and total carbohydrates but did not influence total digestibility of nutrients. Yet, the ground soybeans diet increased the concentration of butyrate and microbial production in the rumen. The diet with ground soybeans supplemented with yerba mate decreased the concentration of acetate and increased the concentration of propionate and increased the efficiency of synthesis and the production of microbial protein in the rumen. There was a positive additive effect of vitamin E in the presence of yerba mate, enhancing the synthesis and production efficiency of microbial protein. Thus, the addition of ground soybeans and antioxidants to diet of buffaloes improves the efficiency of microbial protein synthesis and increases the production of butyrate, without, in general, altering the total digestibility of nutrients.