Açai seed as a fiber source in high-concentrate beef cattle diets and its nutritional effects

Abstract

This study evaluated the effects of different levels of inclusion of coarsely broken açai seed (CBAS) in the diet of feedlot beef cattle on the intake, digestibility, ruminal degradation, passage kinetics, and nitrogen utilization efficiency. Five ruminally fistulated crossbred bulls (387±27kg body weight) were used in a 5×5 Latin square design. A total mixed ration with 750g/kg concentrate and 250g/kg roughage, based on the total dry matter (DM), was used. The treatments consisted of the inclusion of CBAS at 0, 50, 100, 150, and 200g/kg DM as a fiber source in the diet. The roughage used was Mombasa grass silage, which was partially replaced by CBAS. A linear increase in organic matter (OM; P=0.042), crude protein (CP; P=0.023), and neutral detergent fiber (NDF; P=0.022) intake was observed with the inclusion of CBAS in the diet, while a linearly increasing trend was observed for DM (P=0.077) and metabolizable energy (ME; P=0.051) intake. The total, ruminal, and intestinal digestibility of DM and nutrients were not affected by the inclusion of CBAS (P > 0.10). Ruminal ammonia nitrogen decreased linearly (P=0.045), while acetate concentration showed a linear increase (P=0.038), propionate was not affected (P=0.762), and butyrate showed a linear tendency to increase (P=0.086) with the inclusion of CBAS. Passage rate and DM degradation, as well as N utilization were not affected by the inclusion of CBAS (P > 0.10), except for N fecal excretion that showed a linear tendency to increase (P=0.092). Thus, we conclude that CBAS increases organic matter, crude protein, metabolizable energy, and neutral detergent fiber intake in high-concentrate diets without compromising rumen kinetics and nitrogen utilization in beef cattle. Therefore, the CBAS can be considered as an alternative roughage source in scenarios where forage silage of low quality is the fiber source.