The current study assessed ruminal fermentation parameters and bacterial community, nutrient intake, nutrient digestibility and nitrogen balance of goats fed diets containing buffel grass hay and ruminal ammonia nitrogen (N-NH3). Five rumen-cannulated mixed-breed castrated adult goats (45 ± 2.3 kg) were used in a 5 × 5 Latin square design represented by five N-NH3 levels (3.43, 9.95, 17.2, 23.0 and 33.7 mg/dl). Control animals were fed hay exclusively. Other treatments were represented by ruminal infusion composed of a mixture containing urea, ammonium sulphate and casein. The increasing N-NH3 concentrations did not affect rumen fluid pH, which averaged 6.43. Rumen ammoniacal nitrogen increased linearly in response to N-NH3. Volatile fatty acids were not affected by increasing N-NH3 concentrations. A higher abundance of Ruminococcaceae (Ruminococcus 1, Ruminococcaceae UCG-014 and Ruminococcaceae NK4A214 group) was observed in the rumen of goats infused with higher concentrations of N-NH3 (17.2 and 33.7 mg/dl N-NH3). There was a quadratic effect (P < 0.050) of N-NH3 levels on neutral detergent fibre intake with maximum values estimated at 13.7 mg/dl N-NH3. Nutrient intake, nitrogen excretion and nitrogen balance presented a positive linear effect (P < 0.050). In conclusion, 3.43 mg/dl of N-NH3 is the minimum level to maintain microbial activity, whereas the recommended level to optimize the microbial community is 14.5 mg/dl of N-NH3 in the rumen of goats fed buffel grass.

中文翻译：

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饲喂非蛋白氮的山羊：瘤胃细菌群落和瘤胃发酵、采食量、消化率和氮平衡

目前的研究评估了饲喂含野牛干草和瘤胃氨氮 (N-NH) 日粮的山羊的瘤胃发酵参数和细菌群落、养分摄入、养分消化率和氮平衡。3）。五只瘤胃插管混合品种去势成年山羊 (45 ± 2.3 kg) 用于 5 × 5 拉丁方设计，由五个 N-NH 表示3水平（3.43、9.95、17.2、23.0 和 33.7 毫克/分升）。对照动物只喂干草。其他处理以瘤胃输液为代表，瘤胃输液由含有尿素、硫酸铵和酪蛋白的混合物组成。增加的 N-NH3浓度不影响瘤胃液 pH 值，平均为 6.43。瘤胃氨氮响应于 N-NH 线性增加3. 挥发性脂肪酸不受增加 N-NH 的影响3浓度。更高的丰度瘤胃球菌科(瘤胃球菌1、瘤胃球菌科UCG-014 和瘤胃球菌科在注入较高浓度 N-NH 的山羊瘤胃中观察到 NK4A214 组）3（17.2 和 33.7 毫克/分升 N-NH3）。有二次效应（磷< 0.050) N-NH3中性洗涤纤维摄入量的最大值估计为 13.7 mg/dl N-NH3. 养分摄入、氮排泄和氮平衡呈正线性效应（磷< 0.050)。总之，3.43 mg/dl N-NH3是维持微生物活性的最低水平，而优化微生物群落的推荐水平是 14.5 mg/dl N-NH3在山羊的瘤胃中喂食了野牛草。