부산대학교 도서관

Effects of pre-treatment of growing diets with exogenous cellulose/xylanase (Trichoderma ressie) on intake, ruminal fermentation, digestibility, and feeding behavior were evaluated. Five ruminally cannulated crossbred steers (BW = 520 ± 30 kg; experimental units) were used in a 5 × 4 unbalanced Latin-square design. A 2 × 2 factorial treatment arrangement was used: a) diet quality (high [HQ] or low [LQ]); and b) enzyme application (0 or 0.75 mL/kg of diet DM; ABVista, UK). Steers were fed ad-libitum during four 21-d periods (14d adaptation; 7d collections). Wireless ruminal pH probes were used for continuous assessment. Ruminal fluid samples were collected at 2, 4, 8, 16 and 24h after-feeding for VFA analyses. A continuous observation (24h) was used for feeding behavior analyses. Data were analyzed using the GLIMMIX procedures of SAS using collection day as repeated measure. Both DMI and digestible detergent fiber intake were increased (P ≤ 0.05) with addition of enzyme. Steers fed HQ diets consumed more DM, digestible DM, and OM (P ≤ 0.04), and less (P ≤ 0.03) total fiber and digestible fiber than steers fed LQ diets. Mean ruminal pH decreased (P = 0.01) when enzyme was added and when diet was HQ. Molar proportion of ruminal propionate increased (P = 0.01) for steers fed diets containing enzyme. Propionate and valerate molar proportions increased (P < 0.01), while acetate molar proportion as well as acetate:propionate ratio decreased (P < 0.01) for steers fed HQ. Steers tended to spend more time eating (P = 0.09) when fed LQ-enzyme diet. Greater (P < 0.01) eating and chewing was observed for LQ-fed steers. Fibrolytic enzyme as pre-treatment of beef cattle growing diets stimulated intake, positively affected ruminal fermentation without negatively affecting feeding behavior. High quality growing diets positively affected intake, ruminal fermentation, and reduced physical events of consumption.