Abstract
Weaning is a critical stage in the growth and development of piglets, often inducing stress reactions. This study aims to investigate the effects of Parabacteroides distasonis (PBd) derived from Ningxiang pigs on growth performance, intestinal apoptosis, oxidative damage, and inflammation in ETEC-challenged weaned piglets. A total of 22 Duroc × Landrace × Yorkshire (DLY) piglets, 24 days old with similar body weights, were randomly divided into three groups: Control (n = 7), ETEC (n = 7), and PBd + ETEC (n = 8). The results show that, compared to the Control group, ETEC challenge led to decreased growth performance, reduced villus height in the duodenum and jejunum, increased crypt depth in the duodenum, a decreased villus-height-to-crypt-depth ratio, increased expression of apoptosis-related genes (Caspase-8 and Caspase-9), increased expression of oxidative damage-related genes (Nrf2, GSH-PX, mTOR, and Beclin1), increased expression of inflammation-related genes (Myd88, P65, TNF-α, and IL-6), and reduced the contents of SCFAs in the colonic chyme (acetate, propionate, butyrate, valerate, and total SCFAs). Compared to the ETEC group, the PBd + ETEC group alleviated the reduction in growth performance, mitigated intestinal morphological damage, and reduced the expression of the aforementioned apoptosis, oxidative damage, and inflammation-related genes with the increase in SCFAs. In conclusion, PBd derived from Ningxiang pigs effectively reduces ETEC-induced intestinal damage in weaned piglets, improves intestinal health, and increases the content of SCFAs in the colonic chyme, thereby enhancing growth performance.