The present study was to determine the efficacy of dietary supplementation with oleum cinnamomi (OCM) on growth performance and intestinal functions in piglets. Sixteen piglets (24-day-old) were randomly assigned to the control or OCM groups. Piglets in the control group were fed a basal diet, whereas piglets in the OCM group were fed the basal diet supplemented with 50 mg/kg OCM. On day 20 of the trial, blood samples and intestinal tissues were obtained from piglets. Compared with the control group, dietary OCM supplementation increased (p < 0.05) average daily feed intake, plasma insulin levels, villus width and villous surface area in the duodenum and jejunum, DNA levels and RNA/DNA ratios in the ileum, the abundance of Enterococcus genus and Lactobacillus genus in caecum digesta, mRNA levels for epithelial growth factor receptor (EGFR), Ras, extracellular signal-regulated kinase 1/2 (Erk1/2), b-cell lymphoma-extra large (Bcl-xL), villin, junctional adhesion molecule A (JAM-A), myxovirus resistance (MX) 1, MX2 and regenerating islet-derived protein 3 gamma (REG3G), and protein abundances of Ras and claudin-1, but decreased (p < 0.05) diarrhoea incidence; the abundances of Enterobacteriaceae family, Enterococcus genus, Lactobacillus genus, Bifidobacterium genus, and Clostrium coccoides in the colon digesta, and AMP-activated protein kinase (AMPK) mRNA levels and caspase-3 protein abundance in the jejunal mucosa of piglets. Taken together, these data indicate that dietary OCM supplementation modulates intestinal microbiota and improves intestinal function in weanling pigs. OCM is an effective feed additive and alternative to feed antibiotics for improving intestinal health in swine.

l-Tryptophan (Trp) is known to play an important role in the health of the large intestine. However, a role of dietary Trp in the small-intestinal mucosal barrier and microbiota remains poorly understood. The present study was conducted with weaned piglets to address this issue. Postweaning piglets were fed for 4 weeks a corn- and soybean meal-based diet supplemented with 0 (Control), 0.1, 0.2, or 0.4% Trp. The small-intestinal microbiota and serum amino acids were analyzed by bacterial 16S rRNA gene-based high-throughput sequencing methods and high-performance liquid chromatography, respectively. The mRNA levels for genes involved in host defense and the abundances of tight-junction proteins in jejunum and duodenum were measured by real time-PCR and Western blot techniques, respectively. The concentrations of Trp in the serum of Trp-supplemented piglets increased in a dose-dependent manner. Compared with the control group, dietary supplementation with 0.2⁻0.4% Trp reduced the abundances of Clostridium sensu stricto and Streptococcus in the jejunum, increased the abundances of Lactobacillus and Clostridium XI (two species of bacteria that can metabolize Trp) in the jejunum, and augmented the concentrations of secretory immunoglobulin A (sIgA) as well as mRNA levels for porcine β-defensins 2 and 3 in jejunal tissues. Moreover, dietary Trp supplementation activated the mammalian target of rapamycin signaling and increased the abundances of tight-junction proteins (zonula occludens (ZO)-1, ZO-3, and claudin-1) in jejunum and duodenum. We suggested that Trp-metabolizing bacteria in the small intestine of weaned pigs primarily mediated the beneficial effects of dietary Trp on its mucosal integrity, health, and function.

This study aims to determine whether Lactobacillus casei (L. casei) could relieve liver injury in piglets challenged with lipopolysaccharide (LPS). Piglets were randomly allocated into one of the three groups: control, LPS, and L. casei. The control and LPS groups were fed a corn- and soybean meal-based diet, whereas the L. casei group was fed the basal diet supplemented with 6 × 10⁶ cfu/g L. casei. On Day 31 of the trial, piglets in the LPS and L. casei groups received intraperitoneal administration of LPS (100 µg/kg body weight), while the control group received the same volume of saline. Blood and liver samples were collected for analysis. Results showed that L. casei supplementation decreased the feed/gain ratio (p = 0.027) and diarrhea incidence (p < 0.001), and attenuated LPS-induced liver histomorphological abnormalities. Compared with the control group, LPS challenge dramatically increased glutamyl transpeptidase activity (p = 0.001) in plasma as well as the concentrations of Interleukin 6 (IL-6) (p = 0.048), Tumor necrosis factor-alpha (TNF-α) (p = 0.041), and Malondialdehyde (MDA) (p = 0.001) in the liver, while decreasing the hepatic SOD activity. LPS also increased (p < 0.05) the mRNA levels for IL-6, IL-8, TNF-α, Toll-like receptors 4 (TLR4), Nuclear factor κB (NF-κB) and Heat shock protein 70 (HSP70) in the liver. The adverse effects of LPS challenge were ameliorated by L. casei supplementation. In conclusion, dietary L. casei alleviates LPS-induced liver injury via reducing pro-inflammatory cytokines and increasing anti-oxidative capacity.