Comparison of the effects of rumen-protected and unprotected L-leucine on fermentation parameters, bacterial composition, and amino acids metabolism in in vitro rumen batch cultures

作者：Jishan An, Weijun Shen, Hu Liu, Chen Yang, Kemeng Chen, Qiongwen Yuan, Zhiqing Li, Dingfu Xiao, Wang Zuo, Xinyi Lan, Lei Liu, Fachun Wan · 发表于：Frontiers in Microbiology · 年份：2023 · DOI：10.3389/fmicb.2023.1282767 · 被引用次数：21 · 研究领域：Ruminant Nutrition and Digestive Physiology、Muscle metabolism and nutrition、Animal Nutrition and Physiology

This study was conducted to compare the effects of rumen-protected (RP-Leu) and unprotected L -leucine (RU-Leu) on the fermentation parameters, bacterial composition, and amino acid metabolism in vitro rumen batch incubation. The 5.00 g RP-Leu or RU-Leu products were incubated in situ in the rumen of four beef cattle ( Bos taurus ) and removed after 0, 2, 4, 6, 12, 16, and 24 h to determine the rumen protection rate. In in vitro incubation, both RP-Leu and RU-Leu were supplemented 1.5 mmol/bottle ( L -leucine HCl), and incubated after 0, 2, 4, 6, 8, 12, and 16 h to measure gas production (GP), nutrient degradability, fermentation parameters, bacterial composition, and amino acids metabolism. Results from both in vitro and in situ experiments confirmed that the rumen protection rate was greater ( p &lt; 0.01) in RP-Leu than in RU-Leu, whereas the latter was slow ( p &lt; 0.05) degraded within incubation 8 h. Free leucine from RP-Leu and RU-Leu reached a peak at incubation 6 h ( p &lt; 0.01). RU-Leu supplementation increased ( p &lt; 0.05) gas production, microbial crude protein, branched-chain AAs, propionate and branched-chain VFAs concentrations, and Shannon and Sobs index in comparison to the control and RP-Leu supplementation. RU-Leu and RP-Leu supplementation decreased ( p &lt; 0.05) the relative abundance of Bacteroidota , which Firmicutes increased ( p &lt; 0.05). Correlation analysis indicated that there are 5 bacteria at the genus level that ma...