无机铜添加对体外瘤胃微生物发酵的影响

铜是瘤胃微生物活动不可缺少的元素，为研究日粮添加无机铜对瘤胃微生物发酵的影响，本试验用人工瘤胃模拟装置发酵72h研究添加不同水平铜（0、6、12、18、24和30mg/kg干物质（DM））对体外瘤胃微生物发酵挥发性脂肪酸（VFA）产生量、瘤胃液氨浓度和微生物氮产量的影响。结果表明，添加铜可使发酵液不同时间点氨浓度和总氨产量、有机物发酵率显著提高（p<0.05），而对发酵罐中总微生物氮产量没有影响（p>0.05）；与不添加的对照组相比添加铜可使发酵液的总VFA、乙酸、丙酸、丁酸浓度明显增加（p<0.05），但乙酸、丙酸、丁酸摩尔比例没有差异（p>0.05）。添加铜明显促进瘤胃有机物的发酵，增加瘤胃VFA产生量。

Influence of Copper Supplementation on Nitrogen Metabolism and Volatile Fatty Acid Production of Mixed Ruminal Microbial Growth in Continuous Culture Flow-through Fermentors

An experiment was conducted to determine the effects of dietary concentrations of copper on nitrogen metabolism, VFA production and fermentation of mixed ruminal microbes grown in continuous culture fermentors.Six fermentors were fed 40 g of diet.The diet consisted of concentrate and rice straw with Cu supplemented as CuSO4.Dietary treatments were 1) control(no supplemental), 6mg, 12mg, 18mg, 24mg and 30mg of supplemental Cu/kg of DM.The ruminal pH was not greatly affected by Cu supplementation.Ruminal fluid ammonia concentration in continuous ruminal cultures were affected by Cu supplementation(p< 0.05).However, concentrations of ammonia increased(p<0.05) in response to supplemental Cu.The fermen-tation of organ matter was increased by the supplemental Cu.The ruminal fluid VFA concentrations were affected by Cu supplementation(p<0.05).The concentrations of acetate, propionate and butyrate increased(p< 0.05) in response to supplemental Cu.Molar proportions of acetate, propionate and butyrate were not affected by the addition of supplemental Cu to the basal diet.The results indicate that addition of supplemental Cu to the control diets improved growth of ruminal microbe, and increased ruminal fermentation of organ matter and concentrations of VFA in continuous cultures.