Associative Effects of Supplementing Rice Straw with Rapeseed Meal on Performance, Digestion and Ruminal Microbes for Growing Lambs

摘要

Thirty six male Huzhou lambs consuming a rice straw-based diet were used in a 60 days trial to study the associate effects of Rapeseed Meal (RSM) supplementation on digestion, ruminal fermentation parameters, blood biochemical indices and growth performance. All animals were fed rice straw ad libitum together with 120 g day-1 of cornstarch and supplemented with RSM at levels of 0 (control), 80, 160 or 240 g day-1, respectively. Supplemental RSM had no significant effects on feed intake of rice straw (p>0.05) but enhanced the apparent digestibility of organic matter, crude proteins and neutral detergent fiber significantly (p<0.05) with the maximum value at 160 g RSM per day. Daily weight gain of lambs increased linearly with the increasing RSM, reaching 108 g day-1 from 26 for the control. Supplementation of rapeseed with 160 or 240 g day-1 increased significantly serum concentrations of total protein and urea nitrogen (p<0.05) but with no significant effects on triglyceride (p>0.05). The blood glucose concentration rose as the level of supplementation increased. Rumen concentrations of volatile fatty acids, microbial protein and carboxymethyl cellulase activity increased as the proportion of rapeseed increased. When the quantity of supplemented rapeseed reached to 240 g day-1, the increasing rate was mitigated.