Table 1_Enhancing growth performance in Liangshan black sheep through fermented onion: insights from transcriptomics and metabolomics.xlsx

The objective of this study was to assess the effect of fermented onion (FO) on the growth performance of Liangshan black sheep (LBS) and to elucidate its potential molecular mechanisms from a multi-omics perspective. A total of 20 LBS were randomly assigned to one of four groups and fed diets containing 0, 10, 20%, or 30% fermented onions, respectively. The initial and final body weights were recorded. Following the termination of the experiment, the control group and the group exhibiting the most significant increase in average daily gain (ADG) were selected for slaughter. Rumen epithelial tissue was then collected for transcriptome sequencing, while fermented and unfermented onions were collected for untargeted metabolomics. The study revealed that the supplementation of 20% FO led to a notable enhancement in the ADG of LBS, whereas the addition of 30% resulted in a growth-inhibitory effect. Metabolomic analysis revealed that the fermentation process markedly elevated the concentration of bioactive compounds in the onion, including quercetin, rutin, luteolin, myricetin, 4′-methoxyflavone and other flavonoids, as well as linoleic acid, γ-linolenic acid and diverse amino acids. Transcriptome analysis revealed 34 differentially expressed genes (DEGs), which were primarily enriched in protein-related signaling pathways, glycerolipid metabolism, and digestion and absorption-related pathways. The appropriate addition of FO has been demonstrated to promote the growth performance of LBS by increasing the concentration of bioactive substances and regulating metabolic processes and gene expression. The findings of this study provide a scientific basis for improving the growth performance of LBS and making more effective use of onion resources, and contribute new insights to the development and utilization of feeds.本研究旨在评估发酵洋葱（fermented onion, FO）对凉山黑绵羊（Liangshan black sheep, LBS）生长性能的影响，并从多组学视角阐明其潜在分子机制。共计20只凉山黑绵羊被随机分为4组，分别饲喂添加0%、10%、20%或30%发酵洋葱的基础日粮。记录试验羊的初始体重与终末体重。试验结束后，选取对照组与平均日增重（average daily gain, ADG）提升最显著的试验组进行屠宰。随后采集瘤胃上皮组织用于转录组测序，同时采集发酵与未发酵洋葱样品进行非靶向代谢组学分析。研究结果显示，日粮中添加20%的发酵洋葱可显著提升凉山黑绵羊的平均日增重，而添加30%的发酵洋葱则会产生生长抑制作用。代谢组学分析表明，发酵过程显著提高了洋葱中生物活性化合物的含量，包括槲皮素、芦丁、木犀草素、杨梅素、4'-甲氧基黄酮等黄酮类物质，以及亚油酸、γ-亚麻酸与多种氨基酸。转录组学分析共筛选得到34个差异表达基因（differentially expressed genes, DEGs），这些基因主要富集于蛋白质相关信号通路、甘油脂代谢以及消化吸收相关通路。本研究证实，适量添加发酵洋葱可通过提升生物活性物质含量、调控代谢过程与基因表达，进而促进凉山黑绵羊的生长性能。该研究结果为改善凉山黑绵羊的生长性能、高效利用洋葱资源提供了科学依据，同时为饲料的开发与利用提供了新的研究视角。