Gestational and lactational dietary supplementation with live yeast partially attenuates inflammatory responses to lipopolysaccharide challenge in newly weaned piglets

Weaning is an abrupt event in the life of piglets that adversely affects metabolic homeostasis, leading to poor nutrient absorption, increased susceptibility to enteric pathogens, and reduced growth performance. Few studies have examined the effects of maternal dietary live yeast (LY) supplementation on the responses of piglets subjected to an immunological challenge immediately after weaning. The aim of this study was to evaluate the effects of gestational and lactational dietary LY supplementation on inflammatory and antioxidant markers in newly weaned piglets challenged with lipopolysaccharide (LPS). On day 77 of gestation, 40 sows were randomly assigned to two dietary treatments: without (CON) or with LY supplementation at 0.05% of the diet during gestation and 0.1% during lactation. Within 24 h postweaning, 16 piglets with similar weights were selected from each maternal group and intraperitoneally injected with sterile saline or LPS, resulting in four treatment groups (n = 8): 1) CON + saline (CS), 2) LY + saline (YS), 3) CON+ LPS (CLPS), and 4) LY + LPS (YLPS). Rectal temperature was measured hourly for 4 h post-injection, after which piglets were euthanized. Samples of the mesenteric lymph node, liver, muscle, and intestinal mucosa were collected at 4 h post-injection to detect maternal LY-induced physiological changes in piglets. Results showed that YLPS piglets tended to have a lower rectal temperature than CLPS piglets at 3 h post-injection (P = 0.09). Levels of tumor necrosis factor (TNF)-α were decreased in the ileal mucosa of YLPS piglets compared with CLPS piglets (P < 0.05). Additionally, piglets from LY-supplemented sows had higher mRNA abundance of interleukin (IL)-6, IL-10, TNF-α, and IL-1β in the ileal mucosa, with higher protein abundance of E-cadherin in the jejunal mucosa than those from CON sows (P < 0.05). In the liver, YLPS piglets had lower mRNA abundance of nuclear factor kappa B (NF-κB) and toll-like receptor 4 than CLPS piglets (P < 0.05). In the mesenteric lymph node, piglets from LY-supplemented sows had lower gene expression of NF-κB and myeloid differentiation factor 88 than those from CON sows (P < 0.05). These results suggest that maternal dietary LY supplementation may confer protective effects against bacterial endotoxin exposure by attenuating inflammatory responses in newly weaned piglets, with implications for improved resilience to certain gram-negative bacterial infections, such as Escherichia coli, after weaning.