Lin Yitong, Zhao Rong, Zhang Shiyue, Yan Haichao, Sun Jiajin, Zhao Yuqi, Huo Wenjie, Liu Qiang, Wang Cong, Chen Lei, Guo Gang
College of Animal Sciences, Shanxi Agricultural University, Jinzhong 030801, China.
Animals (Basel). 2025 Aug 15;15(16):2394. doi: 10.3390/ani15162394.
This study evaluated the effects of rumen-protected chromium-nicotinic acid (RPCNA) supplementation on lactation performance, nutrient digestion, ruminal fermentation, serum biochemical parameters and antioxidant in lactating water buffaloes under conditions of a critical thermal comfort index (TCI). Healthy lactating water buffaloes (milk yield = 5.96 ± 0.21 kg; parity = 2.96 ± 0.15, mean ± SD) were randomly assigned to four groups, which were the control (without RPCNA), and three treatment groups designated as RPCNA2, RPCNA4, and RPCNA6, with 0, 2, 4, and 6 mg/(d·head) of RPCNA, respectively. During a 56-day experimental period, the average temperature was 29 °C with an average TCI of 40.60, indicating a critical state of environmental stress. The results showed that the addition of RPCNA to the diet had no significant effect on the apparent digestibility of nutrients, lactation performance, and dry matter intake in lactating water buffaloes. However, RPCNA supplementation positively influenced rumen fermentation, reducing ammonia nitrogen (NH-N) concentrations and promoting microbial protein synthesis. Supplementation with RPCNA4 and RPCNA6 decreased rumen NH-N levels by 48.3% and 36.4%, respectively, while RPCNA4 increased isobutyrate concentrations. This demonstrates that the coating technology does not provide 100% rumen protection. Serum analysis revealed that RPCNA significantly increases total antioxidant capacity (T-AOC). Additionally, the supplementation of 4 mg/(d·head) of RPCNA, improved serum glutathione peroxidase (GSH-Px) activity and reduced malondialdehyde (MDA) levels. These findings suggest that moderate doses of RPCNA supplementation can improve antioxidant status and rumen nitrogen metabolism in lactating water buffaloes under critical state, without significantly altering milk production or composition.
本研究评估了在临界热舒适指数（TCI）条件下，添加瘤胃保护性铬-烟酸（RPCNA）对泌乳水牛泌乳性能、养分消化、瘤胃发酵、血清生化参数和抗氧化能力的影响。将健康的泌乳水牛（产奶量 = 5.96 ± 0.21千克；胎次 = 2.96 ± 0.15，均值 ± 标准差）随机分为四组，即对照组（不添加RPCNA）和三个处理组，分别为RPCNA2、RPCNA4和RPCNA6组，每组分别添加0、2、4和6毫克/（天·头）的RPCNA。在为期56天的试验期内，平均温度为29℃，平均TCI为40.60，表明处于环境应激的临界状态。结果表明，日粮中添加RPCNA对泌乳水牛养分的表观消化率、泌乳性能和干物质采食量没有显著影响。然而，添加RPCNA对瘤胃发酵有积极影响，降低了氨氮（NH-N）浓度并促进了微生物蛋白合成。添加RPCNA4和RPCNA6分别使瘤胃NH-N水平降低了48.3%和36.4%，同时RPCNA4增加了异丁酸浓度。这表明包被技术并不能提供100%的瘤胃保护。血清分析显示，RPCNA显著提高了总抗氧化能力（T-AOC）。此外，添加4毫克/（天·头）的RPCNA可提高血清谷胱甘肽过氧化物酶（GSH-Px）活性并降低丙二醛（MDA）水平。这些研究结果表明，在临界状态下，适度剂量的RPCNA添加可改善泌乳水牛的抗氧化状态和瘤胃氮代谢，而不会显著改变产奶量或乳成分。
