Table_2_Impact of precursor-derived peracetic acid on post-weaning diarrhea, intestinal microbiota, and predicted microbial functional genes in weaned pigs.DOCX

Post-weaning diarrhea affects piglets in the nursery phase of production, leading to a substantial impact both at the farm and financial levels. The multifactorial etiology of this disease includes housing conditions, pig genetics, microbial composition, and metagenomic assets. Among the common therapeutic approaches, the widely used zinc oxide underwent a European Union ban in 2022 due to its negative environmental impact and correlation to increased antimicrobial resistance. During this study, we have tested two levels of inclusion of the potential antimicrobial alternative peracetic acid, delivered in water via the hydrolysis of the precursors sodium percarbonate and tetraacetylethylenediamine, in comparison to zinc oxide and an untreated control during a 2-week animal study. We assessed the microbial composition and predicted the metagenome, together with performance and physiological parameters, in order to describe the microbial functional role in etiopathology. Both zinc oxide and peracetic acid resulted in amelioration of the diarrheal status by the end of the trial period, with noticeable zinc oxide effects visible from the first week. This was accompanied by improved performance when compared to the first-week figures and a decreased stomach pH in both peracetic acid levels. A significant reduction in both stomach and caecal Proteobacteria was recorded in the zinc oxide group, and a significant reduction of Campylobacter in the stomach was reported for both zinc oxide and one of the peracetic acid concentrations. Among other functional differences, we found that the predicted ortholog for the zonula occludens toxin, a virulence factor present in pathogens like Escherichia coli and Campylobacter jejuni, was less abundant in the stomach of treated pigs compared to the control group. In water, peracetic acid delivered via precursor hydrolysis has the potential to be a valid intervention, an alternative to antimicrobial, to assist the weaning of piglets. Our findings support the view that post-weaning diarrhea is a complex multifactorial disease with an important metagenomic component characterized by the differential abundance of specific predicted orthologs and microbial genera in the stomach and caecum of pigs.

断奶后腹泻（post-weaning diarrhea, PWD）会影响生产保育阶段的仔猪，给养殖场运营与经济效益均带来显著冲击。该疾病的多因素病因涵盖饲养环境、猪只遗传性状、微生物群落组成及宏基因组特征。在常用治疗手段中，应用广泛的氧化锌（zinc oxide, ZnO）因对环境存在负面影响，且与抗菌素耐药性上升相关，于2022年被欧盟（European Union, EU）禁用。本研究开展了为期2周的动物试验，对比评估了两种添加水平的潜在抗菌替代物——过氧乙酸（peracetic acid, PAA）——的应用效果：过氧乙酸通过前驱体过碳酸钠（sodium percarbonate）与四乙酰乙二胺（tetraacetylethylenediamine, TAED）的水解反应制备后溶于饮水给药，同时设置氧化锌组与未处理对照组。研究人员对仔猪的微生物群落组成进行了检测并预测其宏基因组，同时监测生长性能与生理参数，以阐明微生物在该疾病发病机制中的功能作用。

试验结束时，氧化锌与过氧乙酸均能改善仔猪的腹泻症状，氧化锌的改善效果在第一周即可显现。相较于第一周的数据，两组仔猪的生长性能均得到提升，且两种过氧乙酸添加水平组的胃内pH均有所降低。氧化锌组的胃与盲肠内变形菌门（Proteobacteria）丰度均显著降低，而氧化锌组与其中一种过氧乙酸浓度组的胃内弯曲杆菌属（Campylobacter）丰度均显著下降。在其他功能差异方面，研究团队发现，相较于对照组，处理组仔猪胃内编码紧密连接毒素（zonula occludens toxin, ZOT）的直系同源基因丰度更低——该毒素是大肠杆菌（Escherichia coli）、空肠弯曲杆菌（Campylobacter jejuni）等病原菌携带的毒力因子。

通过前驱体水解制备的饮水型过氧乙酸，有望成为一种有效的抗菌替代干预手段，用于辅助仔猪断奶。本研究结果证实，断奶后腹泻是一种复杂的多因素疾病，其宏基因组组分为核心特征之一，具体表现为仔猪胃与盲肠内特定的预测直系同源基因及微生物属的丰度存在差异。