青贮银合欢作为粗饲料对肉牛生长性能、瘤胃 微生物和氮代谢的影响

Effects of Leucaena silage as a roughage feed on growth performance,rumen microorganism and nitrogen metabolism of beef cattle

文章旨在评估青贮银合欢作为粗饲料对肉牛生长性能、瘤胃微生物及氮代谢的影响。试验将平均初始体重为(291.70±5.70)kg的128头肉牛随机分为4组,每组4个重复,每个重复8头。T1~T4组肉牛在试验期分别自由采食相同的浓缩料,同时分别补充100%水稻秸秆、60%水稻秸秆+40%青贮银合欢、40%水稻秸秆+60%青贮银合欢及100%青贮银合欢。结果:T3组肉牛粗饲料摄入量较T1组显著提高8.54%(P<0.05),同时T2和T3组肉牛的平均日增重较T1组分别显著提高10.74%和12.40%(P<0.05),料重比显著降低8.96%和9.33%(P<0.05)。饲喂后2 h,T3组肉牛瘤胃细菌、真菌、蛋白分解菌及纤维分解菌数量均显著高于T1组(P<0.05),但T1组肉牛瘤胃原生动物数量显著高于T3和T4组(P<0.05)。T4组肉牛氮摄入量、粪氮和尿氮排泄量及氮沉积量最高(P<0.05),同时T2和T3组上述指标均显著高于T1组(P<0.05)。结论:用60%青贮银合欢替代水稻秸秆作为粗饲料饲喂肉牛可以改善饲料效率,提高瘤胃细菌总量,尤其是蛋白和纤维分解菌,同时也提高了氮的沉积和微生物蛋白质的合成。

The aim of this experiment was to evaluate the effects of Leucaena silage as roughage on growth performance,rumen microorganism and nitrogen metabolism of beef cattle.A total of 128 beef cattle with an average initial body weight of(291.70±5.70)kg were randomly divided into 4 groups with 4 replicates of 8 cattle per replicate.Beef cattle in groups T1~T4 were fed the same concentrated feed freely during the whole 8-week feeding experiment period,and supplemented with 100%rice straw,60%rice straw+40%silage leucaena,40%rice straw+60%silage leucaena,and 100%silage leucaena,respectively.Results:Compared with T1 group,the roughage intake of beef cattle in T3 group was significantly increased by 8.54%(P<0.05),meanwhile,the average daily gain of beef cattle in T2 and T3 groups was significantly increased by 10.74%and 12.40%(P<0.05)compared with T1 group,respectively,and the ratio of feed to gain in T3 groups was significantly decreased by 8.96%and 9.33%(P<0.05).2 h after feeding,the number of bacteria,fungi,proteolytic bacteria and fibrolytic bacteria in the rumen of beef cattle in group T3 was significantly higher than that in group T1(P<0.05),but the number of protozoa in the rumen of beef cattle in group T1 was significantly higher than that in groups T3 and T4(P<0.05).The nitrogen intake,fecal nitrogen and urinary nitrogen excretion and nitrogen deposition of beef cattle in T4 group were the highest(P<0.05),and the above indexes in T2 and T3 groups were significantly higher than those in T1 group(P<0.05).Conclusions:Replace rice straw with 60%Leucaena silage as roughage for beef cattle can improve feed efficiency,increase total bacteria,especially protein and fibrolytic bacteria,and also increase nitrogen deposition and microbial protein synthesis.