Oregano essential oil (OEO) has long been used to improve the health of animals, particularly the health of intestine, which is generally attributed to its antimicrobial and anti-inflammatory effects. However, how OEO acts in the intestine of pig is still unclear. This study was aimed at elucidating how OEO promotes the intestinal barrier integrity in a pig model. Pigs were fed a control diet alone or one supplemented with 25 mg/kg of OEO for 4 weeks. The OEO-treated pigs showed decreased (P < 0.05) endotoxin level in serum and increased (P < 0.05) villus height and expression of occludin and zonula occludens-1 (ZO-1) in the jejunum. These results demonstrated that the integrity of intestinal barrier was improved by OEO treatment. The OEO-treated pigs had a lower (P < 0.05) population of Escherichia coli in the jejunum, ileum, and colon than the control. This is in accordance with the greater inactivation (P < 0.05) of inflammation, which was reflected by the mitogen-activated protein kinase (MAPK), protein kinase B (Akt), and nuclear factor κB (NF-κB) signaling pathways and expression of inflammatory cytokines in the jejunum. Our results show that OEO promotes intestinal barrier integrity, probably through modulating intestinal bacteria and immune status in pigs.

With recent bans on the growth-promoting use of antibiotics, alternative strategies are needed to improve the performance of agricultural animals. Here, the effects of dietary supplementation with Clostridium butyricum and a combination of Saccharomyces boulardii and Pediococcus acidilactici were assessed on laying performance, egg quality, oxidative status, and gut health in laying hens. A total of 8208 Lohmann pink laying hens were divided into 3 treatment groups, with each group replicated 12 times (n = 228). Hens in the control group (CON) were provided a basic diet devoid of added antibiotics and probiotics. Treatment group 1 (T1) received the same base diet supplemented with 0.5 g/kg C. butyricum, and the diets of treatment group 2 (T2) supplemented with S. boulardii (0.05 g/kg) and P. acidilactici (0.1 g/kg) for the entirety of the 5-week trial. The data indicated that C. butyricum supplementation resulted in a significant reduction in ADFI, a significant increase in feed conversion, eggshell strength, and the CP% of albumen (dry matter, DM) relative to CON. The probiotic-treated hens exhibited decreased reactive oxygen species (ROS) levels in ileum and cecum, and reduced malondialdehyde (MDA) in serum. In conclusion, dietary supplementation with C. butyricum may be beneficial with respect to hen performance, egg quality, and gut health.

This experiment was conducted to evaluate the effects of quercetin supplementation on intestinal integrity, intestinal reactive oxygen species (ROS) levels and intestinal inflammation in pigs under transport stress. A total of 170 finishing pigs were randomly assigned into two groups. Animals in the control group consumed a basal diet, while those in the treatment group consumed the same diet supplemented with 25 mg quercetin per kg feed. After a 4-week period, pigs were transported for 5 hr. The quercetin-supplemented pigs showed decreased serum levels of endotoxin (P<0.05), increased height of jejunum villi (P<0.05), and increased occludin and zonula occudens-1 (ZO-1) mRNA expression in the jejunum (P<0.05). These parameters are associated with intestinal health and were markedly improved by quercetin supplementation. Pigs consuming the quercetin-supplemented diet had lower intestinal levels of ROS and malondialdehyde (MDA) compared with the control group (P<0.05). This finding coincided with greater inhibition of the innate immune system (P<0.05), including mitogen-activated protein kinase (MAPK), protein kinase B (Akt) and nuclear factor κB (NF-κB) signaling pathways, as well as decreased expression of inflammatory cytokines in the jejunum. These results indicate that quercetin alleviates intestinal injury in pigs during transport, probably through modulation of intestinal oxidative status and inflammation.

The aim of this study was to investigate whether supplementing branched-chain amino acids (AA) (BCAA) along with a reduced-protein diet increases piglet growth, and whether elevated feed intake and muscle growth-promoting effect contribute to this improvement. In Expt 1, twenty-eight weanling piglets were randomly fed one of the following four diets: a positive control (PC) diet, a reduced-protein negative control (NC) diet, an NC diet supplemented with BCAA to the same levels as in the PC diet (test 1 (T1)) and an NC diet supplemented with a 2-fold dose of BCAA in T1 diet (test 2 (T2)) for 28 d. In Expt 2, twenty-one weanling piglets were randomly assigned to NC, T1 and pair-fed T1 (P) groups. NC and T1 diets were the same as in Expt 1, whereas piglets in the P group were individually pair-fed with the NC group. In Expt 1, the NC group had reduced piglet growth and feed intake compared with the PC group, which were restored in T1 and T2 groups, but no differences were detected between T1 and T2 groups. In Expt 2, T1 and P groups showed increases in growth and mass of some muscles compared with the NC group. Increased feed intake after BCAA supplementation was associated with increased mRNA expressions of agoutirelated peptide and co-express neuropeptide Y (NPY) and phosphorylation of mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase 1 (S6K1), as well as decreased mRNA expressions of melanocortin-4 receptor and cocaine-and amphetamine-regulated transcript and phosphorylation of eukaryotic initiation factor 2α in the hypothalamus. No differences were observed among PC, T1 and T2 groups except for higher NPY mRNA expression in the T2 group than in the PC group (Expt 1). Phosphorylation of mTOR and S6K1 in muscle was enhanced after BCAA supplementation, which was independent of change in feed intake (Expt 2). In conclusion, supplementing BCAA to reduced-protein diets increases feed intake and muscle mass, and contributes to better growth performance in piglets.

Previous studies have suggested that immune system development and weaning stress are closely related to the maturation of gut microbiota. The early-life period is a "window of opportunity" for microbial colonization, which potentially has a critical impact on the development of the immune system. Fecal microbiota transplantation (FMT) and probiotics are often used to regulate gut microbial colonization. This study aims to test whether early intervention with FMT using fecal microbiota from gestation sows combined with Clostridium butyricum and Saccharomyces boulardii (FMT-CS) administration could promote the maturation of gut microbiota and development of immune system in piglets. Piglets were assigned to control (n = 84) and FMT-CS treatment (n = 106), which were treated with placebo and bacterial suspension during the first three days after birth, respectively. By 16S rRNA gene sequencing, we found that FMT-CS increased the α-diversity and reduced the unweighted UniFrac distances of the OTU community. Besides, FMT-CS increased the relative abundance of beneficial bacteria, while decreasing that of opportunistic pathogens. FMT-CS also enhanced the relative abundance of genes related to cofactors and vitamin, energy, and amino acid metabolisms during the early-life period. ELISA analysis revealed that FMT-CS gave rise to the plasma concentrations of IL-23, IL-17, and IL-22, as well as the plasma levels of anti-M.hyo and anti-PCV2 antibodies. Furthermore, the FMT-CS-treated piglets showed decreases in inflammation levels and oxidative stress injury, and improvement of intestinal barrier function after weaning as well. Taken together, our results suggest that early-life intervention with FMT-CS could promote the development of innate and adaptive immune system and vaccine efficacy, and subsequently alleviate weaning stress through promoting the maturation of gut microbiota in piglets.