Wiarda Jayne E, Watkins Hannah R, Monson Melissa S, Anderson Christopher L, Loving Crystal L
Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, USA.
Oak Ridge Institute for Science and Education, Agricultural Research Service Participation Program, Oak Ridge, TN, USA.
BMC Vet Res. 2025 Jul 19;21(1):477. doi: 10.1186/s12917-025-04850-5.
Weaning in conventional pig production is a stressful event that involves abrupt dietary and environmental changes, and the post-weaning period is associated with increased incidence of disease and antibiotic use. As a result, there is a growing demand for non-antibiotic practices to enhance health during this phase of production. Current production systems wean piglets at a relatively young age, and it is unclear if age at weaning impacts shifts in intestinal immune populations, particularly intraepithelial T lymphocyte (T-IEL) populations, or bacterial communities, in a comparable timeframe and magnitude. T-IELs reside in the intestinal epithelium and play a role in intestinal integrity and defense. While later weaning may be an approach to minimize the negative impacts of weaning, the impact of age at weaning on T-IEL abundances and function is not clearly understood. Our results indicate pigs weaned at 18-21 days of age (doa; standard weaned, SW), which is consistent with production practices in the United States, had delayed shifts in T-IEL populations when compared to pigs weaned at 25-28 doa (late weaned, LW), which is consistent with practices in the European Union. Specifically, the abundance of induced T-IELs (CD8αβ αβ T cells) in the jejunum increased between 0 and 3 days post-weaning (dpw) for the LW group and stabilized, but shifts were delayed until between 3 and 7dpw in the SW group. Concomitant decreases in the abundance of natural T-IEL (γδ T cells) were detected. The structure of jejunal mucosal bacterial communities were comparable between SW and LW pigs at 0dpw, but the SW group had more pronounced shifts from 3 to 7dpw and 7dpw to 14dpw compared to minimal shift in LW group from 7 to 14dpw. Body weight between groups was comparable when adjusted for age. Overall, the bacterial communities of the jejunal mucosa were more stable after weaning in LW than SW pigs, and jejunal T-IEL abundances stabilized more rapidly in the LW group. As T-IELs play a key role in intestinal homeostasis and barrier integrity, the early differences in population abundance may be indicative of functional differences as well.
在传统养猪生产中，断奶是一个应激事件，涉及到饮食和环境的突然变化，且断奶后阶段疾病发病率和抗生素使用量都会增加。因此，人们对在这一生产阶段采用非抗生素方法来增强健康的需求日益增长。当前的生产系统在仔猪相对年幼时就进行断奶，尚不清楚断奶时的年龄是否会在可比的时间框架和程度上影响肠道免疫群体的变化，特别是上皮内T淋巴细胞（T-IEL）群体或细菌群落的变化。T-IEL存在于肠道上皮中，对肠道完整性和防御起作用。虽然延迟断奶可能是一种尽量减少断奶负面影响的方法，但断奶时的年龄对T-IEL丰度和功能的影响尚不清楚。我们的结果表明，与25 - 28日龄断奶（晚断奶，LW）的仔猪相比，18 - 21日龄断奶（标准断奶，SW）的仔猪，这与美国的生产实践一致，其T-IEL群体的变化延迟，LW组与欧盟的实践一致。具体而言，LW组空肠中诱导型T-IEL（CD8αβ αβ T细胞）的丰度在断奶后0至3天（dpw）增加并稳定下来，但SW组的变化延迟至3至7 dpw。同时检测到天然T-IEL（γδ T细胞）丰度的相应下降。空肠黏膜细菌群落的结构在0 dpw时SW和LW仔猪之间具有可比性，但与LW组从7至14 dpw的微小变化相比，SW组在3至7 dpw和7至14 dpw有更明显的变化。调整年龄后，各组之间的体重具有可比性。总体而言，LW仔猪断奶后空肠黏膜的细菌群落比SW仔猪更稳定，LW组空肠T-IEL丰度更快稳定下来。由于T-IEL在肠道稳态和屏障完整性中起关键作用，群体丰度的早期差异也可能表明功能上的差异。
