Zhao Jian, Zhao Xinsheng, Gao Jian, Bai Binqiang, Niu Jianzhang, Yang Yingkui, Zhao Guojun, Wang Zuojiang, Xu Zhenhua, Wang Jilong, Cheng Yanfen, Hao Lizhuang
Laboratory of Gastrointestinal Microbiology, National Centre for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing 210095, China.
Qinghai University, Key Laboratory of Plateau Grazing Animal Nutrition and Feed Science of Qinghai Province, Xi'ning 810016, China.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae173.
The aim of this study was to investigate the effects of ensiled agricultural byproducts from Qinghai-Tibet plateau on growth performance, rumen microbiota, ruminal epithelium morphology, and nutrient transport-related gene expression in Tibetan sheep. Fourteen male Tibetan sheep were randomly assigned to one of two diets: an untreated diet (without silage inoculum, CON, n = 7) or an ensiled diet (with silage inoculum, ESD, n = 7). The total experimental period lasted for 84 d, including early 14 d as adaption period and remaining 70 d for data collection. The ESD increased average daily gain (P = 0.046), dry matter intake (P < 0.001), ammonia nitrogen (P = 0.045), microbial crude protein (P = 0.034), and total volatile fatty acids concentration (P < 0.001), and decreased ruminal pH value (P = 0.014). The proportion of propionate (P = 0.006) and the copy numbers of bacteria (P = 0.01) and protozoa (P = 0.002) were higher, while the proportion of acetate (P = 0.028) was lower in the sheep fed ESD compared to CON. Pyrosequencing of the 16S ribosomal RNA gene revealed that ESD increased the relative abundance of Firmicutes, Ruminococcus, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, and Christensenellaceae_R-7_group in the rumen (P < 0.05), while decreased the relative abundance of Bacteroidota, Prevotellaceae_UCG-003, and Veillonellaceae_UCG-001 (P < 0.05). Analyses with PICRUSt2 and STAMP indicated that the propionate metabolism pathway was enriched in the sheep fed ESD (P = 0.026). The ESD increased the rumen papillae height (P = 0.012), density (P = 0.036), and surface area (P = 0.001), and improved the thickness of the total epithelia (P = 0.018), stratum corneum (P = 0.040), stratum granulosum (P = 0.042), and stratum spinosum and basale (P = 0.004). The relative mRNA expression of cyclin-dependent Kinase 2, CyclinA2, CyclinD2, zonula occludens-1, Occludin, monocarboxylate transporter isoform 1 (MCT1), MCT4, sodium/potassium pump, and sodium/hydrogen antiporter 3 were higher in the rumen epithelial of sheep fed ESD than CON (P < 0.05). Conversely, the relative mRNA expressions of Caspase 3 and B-cell lymphoma-2 were lower in the sheep fed ESD than CON (P < 0.05). In conclusion, compared with an untreated diet, feeding an ensiled diet altered the rumen microbial community, enhanced nutrient transport through rumen epithelium, and improved the growth performance of Tibetan sheep.
本研究旨在探讨青藏高原青贮农业副产品对藏羊生长性能、瘤胃微生物群、瘤胃上皮形态以及营养物质转运相关基因表达的影响。将14只雄性藏羊随机分为两种日粮组之一：未处理日粮组（无青贮接种物，CON，n = 7）或青贮日粮组（有青贮接种物，ESD，n = 7）。整个试验期持续84天，包括前14天的适应期和其余70天的数据收集期。ESD提高了平均日增重（P = 0.046）、干物质摄入量（P < 0.001）、氨氮（P = 0.045）、微生物粗蛋白（P = 0.034）和总挥发性脂肪酸浓度（P < 0.001），并降低了瘤胃pH值（P = 0.014）。与CON组相比，ESD组藏羊的丙酸比例（P = 0.006）以及细菌（P = 0.01）和原虫（P = 0.002）的拷贝数更高，而乙酸比例（P = 0.028）更低。对16S核糖体RNA基因进行焦磷酸测序显示，ESD增加了瘤胃中厚壁菌门、瘤胃球菌属、毛螺菌科_AC2044_组、毛螺菌科_XPB1014_组和克里斯滕森菌科_R-7_组的相对丰度（P < 0.05），同时降低了拟杆菌门、普雷沃氏菌科_UCG-003和韦荣氏菌科_UCG-001的相对丰度（P < 0.05）。使用PICRUSt2和STAMP进行分析表明，丙酸代谢途径在ESD组藏羊中富集（P = 0.026）。ESD增加了瘤胃乳头高度（P = 0.012）、密度（P = 0.036）和表面积（P = 0.001），并改善了总上皮厚度（P = 0.018）、角质层厚度（P = 0.040）、颗粒层厚度（P = 0.042）以及棘层和基底层厚度（P = 0.004）。与CON组相比，ESD组藏羊瘤胃上皮中细胞周期蛋白依赖性激酶2、细胞周期蛋白A2、细胞周期蛋白D2、闭合蛋白-1、闭合蛋白、单羧酸转运体亚型1（MCT1）、MCT4、钠/钾泵和钠/氢反向转运体3的相对mRNA表达更高（P < 0.05）。相反，ESD组藏羊中半胱天冬酶3和B细胞淋巴瘤-2的相对mRNA表达低于CON组（P < 0.05）。总之，与未处理日粮相比，饲喂青贮日粮改变了瘤胃微生物群落，增强了营养物质通过瘤胃上皮的转运，并改善了藏羊的生长性能。
