饲粮中添加海南霉素和莫能菌素对奶牛瘤胃蛋白质降解和产氨菌群的影响

【目的】研究饲粮中添加海南霉素和莫能菌素对奶牛瘤胃蛋白质降解和产氨菌群的影响。【方法】选用3头体重（460±20.6）kg、装有永久性瘤胃瘘管的成年荷斯坦奶牛，采用3×3拉丁方设计，对照组饲喂基础日粮，处理组分别在基础日粮的基础上添加莫能菌素150 mg?d-1和海南霉素75 mg?d-1。【结果】日粮添加海南霉素和莫能菌素，瘤胃中栖瘤胃普雷沃氏菌数量均显著高于对照组（P＜0.05），而溶纤维丁酸弧菌和高效产氨菌数量显著低于对照组（P＜0.05），对瘤胃埃氏巨球型菌、反刍兽新月单胞菌和牛链球菌数量没有影响（P＞0.05）。与对照组相比，日粮添加海南霉素和莫能菌素增加了瘤胃肽氮和氨基酸氮浓度（P＜0.05），降低了氨态氮浓度和脱氨酶活力（P＜0.05），对蛋白酶活力没有影响（P＞0.05）。海南霉素和莫能菌素两组间的所有指标差异均不显著（P＞0.05）。【结论】与莫能菌素相似，海南霉素具有节约“蛋白质”的作用，并且也是通过对特定产氨细菌的影响来调控蛋白质到氨态氮整个降解过程。

Effects of Dietary Supplementation with Hainanmycin or Monensin on Ruminal Protein Degradation and Populations of Ammonia-Producing Bacteria in Dairy Cows

【Objective】The study was conducted to evaluate the effects of dietary supplementation with hainanmycin or monensin on ruminal protein degradation and populations of ammonia-producing bacteria.【Method】Three ruminally cannulated cows were randomly assigned to treatments in a 3×3 Latin square design with a 12-d period.The three dietary treatments were: a control diet,control diet plus supplemental Hainanmycin at 75 mg·d-1,and control diet plus supplemental monensin at 150 mg·d-1.【Result】The results showed that ruminal relative population sizes of Prevotella ruminicola of cows supplemented with hainanmycin or monensin were higher than the control significantly(P<0.05),and that of Butyrivibrio fibrisolvens and ammonia-hyperproducing bacteria were lower than the control significantly(P<0.05).However,ionophore had no effect on relative population sizes of Megasphaera elsdenii,Selenomonas ruminantium and Streptococcus bovis(P>0.05).Compared with the control,hainanmycin or monensin supplementation increased peptide nitrogen and amino acid nitrogen concentration(P<0.05) and reduced ammonia concentration and deaminase activity(P<0.05),and had no effect on proteinase activity(P>0.05).There were no difference between hainanmycin and monensin(P>0.05).【Conclusion】Similarly to monensin,hainanmycin had the protein-sparing effect,and could modify degradation of protein by changing specified ammonia-producing bacteria.