Butyrate provides energy for colonocytes and is a functional metabolite that mitigates weanling piglet stress. However, its effects and mechanisms remain largely unknown. We established a lipopolysaccharide (LPS)-induced inflammatory stress piglet model to examine how butyrate mechanisms impacted piglet intestinal histology, microbiota, and inflammation. We randomly assigned 18 crossbred male piglets to three treatment groups: CON, LPS, and BT-LPS. Coated butyrate was supplemented in the BT-LPS feed for 21 days. On days 19 and 21, piglets in LPS and BT-LPS groups were challenged with LPS at 100 μg/kg body weight. Dietary butyrate improved LPS-injured intestinal histology by significantly increasing jejunal and ileal villus height, villus height to crypt depth ratios, and decreasing histological scores. LPS challenge activated hypoxia-inducible factor 1α and nuclear factor-κB, and enhanced interleukins (IL-1β, IL-6, IL-12), tumor necrosis factor-α, and also downstream inducible nitric oxide synthase and cyclooxygenase 2, but decreased anti-inflammatory cytokines (IL-10, IL-13). Most molecule levels were significantly reversed by butyrate administration. When compared with the CON or LPS groups, the BT-LPS group had a higher relative abundance of jejunal Firmicutes, Bacteroidetes, Clostridiaceae, Lactobacillus, and Prevotella but a lower abundance of Proteobacteria, Enterobacteriaceae, and Escherichia–Shigella. Phylogenetic investigation of communities by reconstruction of unobserved states and correlation analyses suggested these bacteria contributed to butyrate-alleviating jejunal inflammation and infectious diseases. Butyrate-based diets significantly reduced apoptosis via mitochondrial pathways by downregulating apoptotic caspase 3 mRNA levels. Diets also altered enterocyte metabolism in the jejunum by upregulating peroxisome-proliferator-activated receptor α expression but downregulating carnitine palmitoyltransferase 1 level when compared with CON or LPS groups. Butyrate supplementation improved immunity homeostasis, generated beneficial shifts in microbial communities, improved enterocyte energy metabolism, and prevented apoptosis to protect intestinal histology from LPS-induced injury.

The study was conducted to investigate the effects of replacing antibiotic growth promoters (AGPs) with an egg immunoglobulin (IgY) combined with phytomolecules (PM) on the growth rate, serum immunity, and intestinal health of weaned pigs challenged with Escherichia coli K88 (E. coli K88). A total of 192 piglets were weaned at 28 days old with an average weight of 7.29 (± 0.04) kg. They were randomly divided into four treatments containing eight replicates with six piglets per replicate. The treatment groups were NC and PC fed a basal diet, AGP fed a basal diet supplemented with 75 mg/kg chlortetracycline, 50 mg/kg oxytetracycline calcium, and 40 mg/kg zinc bacitracin, IPM fed a basal diet supplemented with IgY at dose of 2.5 g/kg and 1.0 g/kg and PM at dose of 300 mg/kg and 150 mg/kg during days 1 to 17 and 18 to 42, respectively. On days 7 to 9 of the experiment, piglets in the PC, AGP, and IPM groups were orally challenged with 20 mL E. coli K88 (10⁹ CFU/mL), while piglets in the NC group were challenged with 20 mL medium without E. coli K88. The E. coli K88 challenge model was successful as the incidence of post-weaning diarrhea (PWD) of piglets challenged with E. coli K88 was significantly higher than that of those unchallenged piglets during the challenge time (days 7 to 9) and days 1 to 7 of post-challenge (p < 0.05). A diet with combinations of IgY and PM and AGPs significantly decreased the incidence of PWD during the challenge time and days 1 to 7 of post-challenge (p < 0.05) compared to the PC group and significantly improved the ratio of feed to weight gain (F:G) during days 1 to 17 of the experiment compared to the NC and PC groups (p < 0.05). In comparison with the PC group, piglets in the IPM group had significantly higher serum levels of IgA, IgG, and IgM (p < 0.05), but lower serum IL-1β on day 17 of experiement (p < 0.05). Besides, diet supplementation with AGP significantly decreased serum IL-1β, IL-6, and TNF-α on days 17 and 42 (p < 0.05) with comparison to the PC group. Piglets in the IPM group showed a significantly lower level of fecal coliforms (p < 0.05), but a higher villus height of jejunum and ileum and higher ratio of villus height to crypt depth of duodenum and jejunum (p < 0.05) than those piglets in the PC group. In summary, diet supplementation with a mixture of IgY and PM decreased the incidence of PWD and coliforms, increased feed conversion ratio, and improved intestinal histology and immune function.