Live yeast dietary supplementation acts upon intestinal morpho-functional aspects and growth in weanling piglets

Three hundred and fifty-two piglets were at weaning assigned to two dietary experimental groups, Ctr (control) or Y (yeast-supplemented). The yeast supplement (2 g/kg of diet) provided 2 x 106 CFU/g of feed. Piglet growth was monitored from weaning to 4 weeks after weaning. On day 28 post-weaning, 20 female piglets (10 per group) were slaughtered and the distal ileum was sampled from each animal, and examined with microanatomical methods (histology, histochemistry, immunohistochemistry, and histometry). Villus and crypt measurements were taken, mucin profile assessed with histochemistry, and mucosal macrophages and proliferating epithelial cells determined after immunolocalization. Yeast supplementation to piglets was associated with a greater live weight (P < 0.001) and a greater post-weaning daily gain (P < 0.001) in comparison with control animals. The intestinal adherent mucous layer was thicker in control than supplemented piglets (P < 0.001). Proliferating epithelial cell counts were greater in supplemented than control piglets (P=0.045). Mucosal macrophages were more numerous in supplemented than control piglets (P=0.007). These findings indicate that live yeast dietary supplementation to piglets is able to improve nursery growth performance. Effects on intestinal mucosa suggest that supplementation is able to promote a "healthy" intestine, encouraging an early restoration of the intestinal mucosal thinning that often occurs at weaning, and possibly improving local resistance to infection.