PSII-B-18 - açai Seed as Fiber Source on Intake, Digestibility and Ruminal Parameters in Zebu Beef Cattle Fed a High Concentrate Diet

Abstract: This study was designed to evaluate the effects of açaí seed (AS) as a fiber source on intake, digestibility, and ruminal fermentation parameters of beef cattle fed a high concentrate diet. Five rumen-fistulated Zebu bulls were used in a 5x5 Latin-square design. Treatments consisted of five diets with different inclusion rates of AS: 0, 5, 10, 15, and 20% of the diet dry matter (DM). The total mixed ration contained 75% of concentrate and 25% of roughage. Mombasa grass silage and AS were used as the roughage sources. The concentrate portion of the diet contained cracked corn (61.8%), soybean meal (8%) and vitamin/mineral premix (5.2% of DM). Each experimental period lasted 25 d and the last 11 d were used for data collection. Total fecal collections were performed over three days. Titanium dioxide was used to estimate the omasal outflow. Statistical significance was declared at P < 0.05, and tendency at 0.05 > P < 0.10. A linear increase was observed for DM (P= 0.07), organic matter (P < 0.05), crude protein (CP, P < 0.05), and neutral detergent fiber (NDF) intake with the inclusion rate of AS. Intake was greatest in bulls receiving diets containing 20% AS. A linear decrease (P< 0.05) in NDF digestibility was detected with the inclusion rate of AS. DM, CP digestibility, and metabolic energy were similar across treatments (P > 0.10). Ruminal and intestinal DM and nutrient digestibility were similar between the treatments (P > 0.10). Rumen concentrations of acetic acid increased (P < 0.05), and total short-chain fatty acids (P = 0.07) and butyrate (P = 0.08) tended to increase linearly with the inclusion of AS. Açaí seed as a source of fiber in confined Zebu bulls diets alters DM intake and rumen fermentation but has no impact on total tract DM digestibility.