Effects of increasing dietary rice straw level on chewing activity, ruminal fermentation, fibrolytic enzyme activity and blood biochemical profile in growing goats

摘要

Effects of increasing dietary rice straw on the responses of goats were investigated by a 4×4 Latin Square Design. The goats were offered 1 of 4 diets with increasing proportion of rice straw (i.e. 0.05, 0.10, 0.15 and 0.20 rice straw, respectively). Dietary rice straw significantly increased (P<0.05) the time spent eating, ruminating and chewing activities. The pH value and acetate: propionate were significantly (P<0.05) increased in rumen, while the NH3-H concentration was significantly (P<0.05) decreased. Increasing rice straw significantly affected (P<0.05) the some individual VFA concentration in rumen, such as increased molar proportion of acetate and isovalerate, and decreased molar proportion of propionate. Fibrolytic enzymes activities in rumen were greatly influenced (P<0.05) by the increased dietary rice straw level, such as decreased CMCase, xylanase and cellobiase activities, and increased the avicelase activities. The blood biochemical parameters were hardly affected by the rice straw, except blood urea N. Blood motilin firstly increased and then decreased with the highest value occurring at 8 h after feeding across four treatments. In summary, increased rice straw has great impact on chewing activity and ruminal fermentation, and has little effect on energy metabolism in goats.