Abstract

This study was conducted to examine the effects of neem (Azadirachta indica) seed oil (NSO) on feed intake, ruminal fermentability, feed digestibility, nitrogen balance, and blood parameters in Omani sheep. Nine Omani male sheep (BW; 54.44 ± 8 kg/sheep) were used in a replicated 3 × 3 Latin Square design with three dietary treatments and three periods, with each period lasting 21 days. The animals were randomly assigned into three treatment groups: basal diet without NSO (control); 20 mL/sheep per day NSO (low dose) or 40 mL/sheep per day NSO (high dose). Sheep fed with high dose presented lower (p < 0.05) intake, fiber digestibility, and excreted N in urine. However, diet supplemented with high NSO dose had a lower (p < 0.05) ruminal acetate proportion, while increased (p < 0.05) ruminal propionate compared to the control group. Moreover, sheep offered with NSO showed a linear decrease (p = 0.052) in ruminal ammonia nitrogen (NH₃-N) concentration. The high dose increased (p < 0.05) blood glucose and cholesterol, while decreased urea nitrogen concentrations. Emission of predicted methane (CH₄) reduced (p = 0.007) by 13% for high dose compared to the control group. In conclusion, these results suggested that NSO is a potential feed additive with up to 20 ml/kg of DM alters rumen fermentation profile, decreased CH₄ production, feed digestibility, and nitrogen metabolism for sheep.

摘要

本研究旨在检测印楝 ( Azadirachta indica ) 种子油 (NSO) 对阿曼绵羊采食量、瘤胃发酵能力、饲料消化率、氮平衡和血液参数的影响。9 只阿曼雄性绵羊（体重；54.44 ± 8 千克/只羊）被用于重复的 3 × 3 拉丁方设计，具有三种饮食处理和三个时期，每个时期持续 21 天。这些动物被随机分配到三个治疗组：不含 NSO 的基础饮食（对照组）；每天 20 mL/羊 NSO（低剂量）或 40 mL/羊每天 NSO（高剂量）。喂养高剂量的绵羊表现出较低的 ( p  < 0.05) 摄入量、纤维消化率和尿液中排泄的 N。然而，补充高剂量 NSO 的饮食具有较低的（p < 0.05) 瘤胃乙酸盐比例，同时 与对照组相比增加 ( p < 0.05) 瘤胃丙酸盐。此外，提供 NSO 的绵羊 瘤胃氨氮 (NH ₃ -N) 浓度呈线性下降 ( p = 0.052)。高剂量增加 ( p  < 0.05) 血糖和胆固醇，同时降低尿素氮浓度。与对照组相比，高剂量组的预测甲烷 (CH ₄ ) 排放量减少 ( p  = 0.007) 13%。总之，这些结果表明 NSO 是一种潜在的饲料添加剂，高达 20 ml/kg 的 DM 会改变瘤胃发酵曲线，降低 CH ₄羊的生产、饲料消化率和氮代谢。