Role of iron in host-microbiota interaction and its effects on intestinal mucosal growth and immune plasticity in a piglet model.

Iron is an essential trace element for both the host and resident microbes in the gut. In this study, iron was administered orally and parenterally to anemic piglets to investigate the role of iron in host-microbiota interaction and its effects on intestinal mucosal growth and immune plasticity. We found that oral iron administration easily increased the abundance of Proteobacteria and Escherichia-Shigella, and decreased the abundance of Lactobacillus in the ileum. Furthermore, similar bacterial changes, namely an increase in Proteobacteria, Escherichia-Shigella, and Fusobacterium and a reduction in the Christensenellaceae_R-7_group, were observed in the colon of both iron-supplemented groups. Spearman's correlation analysis indicated that the changed Fusobacterium, Fusobacteria and Proteobacteria in the colon were positively correlated with hemoglobin, colon and spleen iron levels. Nevertheless, it was found that activated mTOR1 signaling, improved villous height and crypt depth in the ileum, enhanced immune communication, and increased protein expression of IL-22 and IL-10 in the colon of both iron-supplemented groups. In conclusion, the benefits of improved host iron outweigh the risks of altered gut microbiota for intestinal mucosal growth and immune regulation in treating iron deficiency anemia.

Dietary lysozyme supplementation contributes to enhanced intestinal functions and gut microflora of piglets.

Lysozyme plays a significant role in defense against bacterial pathogens and in regulating the interactions between gut microbiota and host immune systems. Here, the effects of dietary lysozyme on the intestinal development, immunity, and colonic microbiota of piglets were comprehensively evaluated. Twenty-four seven-day-old piglets from Landrace × Yorkshire sows (n = 8 per group) received no supplementation (group A, the control), 0.5 g kg-1 lysozyme (group B), or 1.0 g kg-1 lysozyme (group C). After the 14-day treatment, piglets supplemented with 1.0 g kg-1 lysozyme had higher average weaning weight, jejunal villus height (VH), and ileal lymphocyte counts than those in the control groups (P < 0.005). Serum total protein and albumin were significantly up-regulated (P < 0.005) and immunoglobulin G tended to increase in the 0.5 g kg-1 lysozyme group (P = 0.065). Bacteroidetes, Proteobacteria, and Fibrobacteres all showed a significant increase in relative abundance after lysozyme treatment at the highest dosage (P < 0.005). At the genus level, the relative abundance of Lactobacillus, Treponema_2, and Prevotellaceae_NK3B31_group was significantly increased in the lysozyme-treated groups. Furthermore, microbial genes related to glycerolipid, propanoate, and pyruvate metabolism showed much more abundance in the 1.0 g kg-1 lysozyme group. Interleukin-4 in the colonic mucosa was significantly up-regulated, while transforming growth factor-ß1 showed significant reduction in the lysozyme-treated group. Moreover, mucosal catalase and malondialdehyde in colon samples increased significantly. These results demonstrate that dietary lysozyme efficaciously improves the development of intestinal structure and functions and promotes the enrichment of beneficial microbes in the gut microbiota in terms of both composition and metabolic functions.

Salvianolic acid B attenuates experimental skin fibrosis of systemic sclerosis.

Systemic sclerosis (SSc) is a connective tissue disease characterized mainly by fibrosis of skin and internal organs. Our previous study has shown that salvianolic acid B (SAB), a bioactive component extracted from Salvia miltiorrhiza (SM), was one of the essential ingredients in the traditional Chinese medicine Yiqihuoxue formula, which has been used to treat SSc-related dermal and pulmonary fibrosis. The aim of the present study was to evaluate the effect of SAB on skin fibrosis and explore its underlying anti-fibrotic mechanism. We found that SAB was capable of alleviating skin fibrosis in a bleomycin-induced SSc mouse model, alleviating skin thickness and reducing collagen deposition. in vitro studies indicated that SAB reduced SSc skin fibroblast proliferation and downregulated extracellular matrix gene transcription and collagen protein expression. TGF-ß/SMAD and MAPK/ERK pathway activation were also shown to be suppressed in SAB treated fibroblasts. Moreover, RNA-seq revealed that the anti-fibrotic effect of SAB might be related to antioxidant activity, the cell cycle, and the p53 signaling pathway. Taken together, our results suggest that SAB has the ability to alleviate SSc-related skin fibrosis both in vivo and in vitro.

Effects of dietary n-6:n-3 PUFA ratio on fatty acid composition, free amino acid profile and gene expression of transporters in finishing pigs.

Revealing the expression patterns of fatty acid and amino acid transporters as affected by dietary n-6:n-3 PUFA ratio would be useful for further clarifying the importance of the balance between n-6 and n-3 PUFA. A total of ninety-six finishing pigs were fed one of four diets with the ratio of 1:1, 2·5:1, 5:1 and 10:1. Pigs fed the dietary n-6:n-3 PUFA ratio of 5:1 had the highest (P< 0·05) daily weight gain, and those fed the dietary n-6:n-3 PUFA ratio of 1:1 had the largest loin muscle area (P< 0·01). The concentration of n-3 PUFA was raised as the ratio declined (P< 0·05) in the longissimus dorsi and subcutaneous adipose tissue. The contents of tryptophan, tasty amino acids and branched-chain amino acids in the longissimus dorsi were enhanced in pigs fed the dietary n-6:n-3 PUFA ratios of 1:1-5:1. The mRNA expression level of the fatty acid transporter fatty acid transport protein-1 (FATP-1) was declined (P< 0·05) in the longissimus dorsi of pigs fed the dietary n-6:n-3 PUFA ratios of 1:1-5:1, and increased (P< 0·05) in the subcutaneous adipose tissue of pigs fed the dietary n-6:n-3 PUFA ratios of 5:1 and 10:1. The expression profile of FATP-4 was similar to those of FATP-1 in the adipose tissue. The mRNA expression level of the amino acid transceptors LAT1 and SNAT2 was up-regulated (P< 0·05) in the longissimus dorsi of pigs fed the dietary n-6:n-3 PUFA ratios of 1:1 and 2·5:1. In conclusion, maintaining the dietary n-6:n-3 PUFA ratios of 1:1-5:1 would facilitate the absorption and utilisation of fatty acids and free amino acids, and result in improved muscle and adipose composition.