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The use of next-generation probiotics (NGP) in pigs for combating diseases has been subject to limited research. Here we explored the potential of a well-known NGP candidate Akkermansia muciniphilatargeting pig gut health. In the first screening experiment, we found that the abundance of A. muciniphilapeaked at 14 d old but decreased at weaning (21 d old; P < 0.05), suggesting the weaning period may be an effective window for A. muciniphilaintervention. Following that, 48 crossbred weaned pigs at 28 d old were randomly assigned to five groups: control (CON), high/low live A. muciniphila(HA/LA), and high/low heat-killed A. muciniphila(HIA/LIA). From 1 to 28 d old, the CON group received gastric infusion of anaerobic sterile saline every other day; the HA and LA groups were gavaged every other day with 1 × 1010 CFU/5 mL and 5 × 108 CFU/5 mL live A. muciniphila, respectively; and the HIA and LIA groups were gavaged every other day with 1 × 1010 CFU/5 mL and 5 × 108 CFU/5 mL heat-killed A. muciniphila, respectively. At d 29, pigs in the CON group were randomly and equally divided into two groups, one of which was named the enterotoxigenic Escherichia coli(ETEC) group, and all groups except CON received a 5-d ETEC challenge. The supplementation of A. muciniphilanumerically reduced the diarrhea rate of weaned pigs compared to the pigs that only received the ETEC challenge (P = 0.57), but the LIA group had a higher diarrhea rate than the CON group (P < 0.05). Consistent with this, the supplementation of A. muciniphilaimproved the small intestinal morphology and structure, proportion of CD4+T lymphocytes in the blood, as well as the expression of genes related to intestinal barrier and antioxidant indices of pigs with ETEC challenge, especially for the LA group (P < 0.05). Meanwhile, A. muciniphilasupplementation reduced the expression of ETEC virulence factor genes in the ileum and colon of pigs challenged by ETEC (P < 0.05). Therefore, A. muciniphilamay protect the intestinal health of weaned piglets from damage caused by ETEC infection, but the effect may vary depending on the concentration and activity of A. muciniphila.

The purpose of this research was to investigate how different bile acids impact lipid metabolism and carcass characteristics in finishing pigs, along with the potential mechanisms involved. Twenty-one finishing pigs (DLY; average BW = 144.38 ± 8.92 kg) were assigned to three dietary treatments, with each treatment containing seven replicates, each consisting of one pig. The three dietary treatments included: a basic diet, a basic diet supplemented with 500 mg/kg of hyodeoxycholic acid (HDCA), and a basic diet supplemented with 500 mg/kg of lithocholic acid (LCA). The trial lasted for 28 d. Hyodeoxycholic acid was used in the in vitro experiments and added to mature 3T3-L1 adipocytes for 4 d to elucidate the mechanism by which bile acids regulate lipid metabolism. The results suggested that HDCA tended to decrease backfat thickness in finishing pigs (P= 0.094) and reduced the size of lipid droplets in 3T3-L1 adipocytes (P= 0.012), whereas LCA increased backfat thickness (P= 0.016) and induced larger lipid droplets in the abdominal adipose tissue (P= 0.003). Furthermore, HDCA enhanced the expression of Takeda G-protein-coupled receptor 5 protein and hormone-sensitive lipase (HSL) gene in backfat of pigs (P< 0.05) and increased the protein expression of phosphorylated HSL (p-HSL) in vitro (P= 0.093). Compared to HDCA, LCA addition increased the gene and protein expression of peroxisome proliferator activated receptor gamma in backfat of pigs (P< 0.05) and enhanced the expression of hepatic genes sterol regulatory element-binding protein-1c and fatty acid synthase (P< 0.05). In conclusion, HDCA enhanced lipolysis and partially decreased backfat thickness in finishing pigs, while LCA promoted lipid synthesis and increased backfat thickness of pigs. The variations in the effects of various bile acids on bile acid receptors could explain these functional differences.

This experiment was conducted to investigate the effects of benzoic acid, Bacilluscoagulans and oregano oil combined supplementation on growth performance, immune status and intestinal barrier integrity of piglets. In a 26-d experiment, 25 piglets were randomly assigned to 5 treatments: 1) a basal diet, negative control (NC), 2) NC added with antibiotics, positive control (PC); 3) NC added with benzoic acid at 3,000 g/t and Bacilluscoagulans at 400 g/t (AB); 4) NC added with benzoic acid at 3,000 g/t and oregano oil at 400 g/t (AO); 5) NC added with 3,000 g/t benzoic acid and Bacilluscoagulans at 400 g/t and oregano oil at 400 g/t (ABO). On d 27, all piglets were euthanized to obtain jejunal mucosa to measure immune status and intestinal barrier integrity. Results showed that pigs fed AB diet increased the final body weight and average daily body weight gain and decreased the ratio of feed to gain compared with NC group (P< 0.05). Compared with NC group, AB, AO and ABO decreased serum tumor necrosis factor-α concentration and ABO decreased interleukin-1β concentration in serum and jejunal mucosa (P< 0.05). Compared with NC group, AB up-regulated mRNA expressions of sodium-glucose cotransporte1, claudin-1, occludin and mucin2 in jejunal mucosa and the populations of Bifidobacteriumand Bacillusin cecal digesta (P< 0.05). Compared with NC group, ABO increased jejunal mucosal occludin mRNA abundance and Bifidobacteriumpopulation in cecal digesta, and decreased Escherichia colipopulation in cecal digesta (P< 0.05). Furthermore, AB and ABO increased Bacillus population in cecal digesta compared with PC group (P< 0.05). These results indicated that dietary AB supplementation could improve growth performance and intestinal barrier integrity of piglets when fed antibiotic-free diets, which was possibly associated with the improvement of immune status and intestinal microflora. Dietary ABO supplementation is also beneficial to improve immune status and intestinal barrier integrity and microflora of piglets.