ABSTRACT To characterize the N6-methyladenosine (m6A)-related gene expression profiles in various tissues of Meishan pigs at different stages, m6A modification-related genes (METTL3, METTL14, METTL16, WTAP, RBM15, and FTO) were detected from newborn to physical maturity of Meishan pigs at eight important developmental stages (1, 7, 14, 21, 28, 35, 134, and 158 days old). The expression of m6A-related genes was tissue-specific. Furthermore, the level of METTL3 messenger RNA (mRNA) was higher on day 35 than in other stages in most tissues, and the expression of METTL14 increased after day 35, and FTO exhibited a peak on day 14 in muscle, intestine, lymph nodes, thymus, and kidney. This study provided a reference for an in-depth study of the expression patterns of m6A modification-related genes in Meishan pigs.

ABSTRACT To screen intestinal barrier genes associated with porcine epidemic diarrhea virus (PEDV) infection, in the present study we first detected PEDV-infected piglets ( Sus scrofa ) with intestinal damage using quantitative real-time PCR (qPCR) and hematoxylin and eosin (HE) staining. Then, we used qPCR to identify expression differences of intestinal barrier genes between the PEDV-infected and control groups. The results showed that the expression levels of most genes were significantly different between the two groups. Hierarchical clustering and correlation analysis were performed for the expression levels of 25 candidate genes to reveal the key gene that may be involved in PEDV resistance. Two important candidate genes, GLP2 (glucagon–like peptide 2) and AQP3 (aquaporin 3), have their expression positively correlated (r = 0.84). We speculated that decreased expression of GLP2 and AQP3 might play an important role in the process of PEDV infection of piglets by reducing the expression of tight junction proteins and disrupting the junctions between intestinal epithelial cells. There may be an underlying biological interaction between the two genes, which together affect the functional integrity of the intestinal barrier.

ABSTRACT To understand the developmental expression patterns of key genes in the Toll-like receptor 4 ( TLR4 ) pathway and their regulatory characteristics in the immune response in pigs, we examined TLR4 and its downstream genes expression levels in the intestinal and immune tissues of Meishan pigs. The genes were expressed in all examined tissues at the different developmental stages. TLR4 expression was higher in spleen and lower in other tissues. Spleen and lymph TLR4 expression was significantly lower in 7- and 35-day-old pigs; in the intestinal tissues, it was significantly lower in 21- and 35-day-old pigs. IFNA, IL1B , and TNFA expression varied greatly with developmental stage; expression was significantly higher in most tissues in 21-, 134-, and 158-day-old pigs. TLR4 was highly positively correlated with TNFA in the immune tissues and was significantly correlated with all downstream genes in the spleen; there was no significant correlation in the intestinal tissues. There was near significant positive correlation among the downstream genes in the intestinal tissues, but almost no significant correlation in the immune tissues. We speculated that the TLR4 pathway genes may have an anti-lipopolysaccharide invasion effect during weaning, and the high expression of the downstream genes is beneficial for improving immunity in adult pigs. Our results may contribute to better understanding the TLR4 signaling pathway and its molecular mechanisms and could provide a reference and basis for appropriate-age experimental animal selection for relevant future research.

ABSTRACT This study evaluated the effect of fermented soybean meal (FSBM) supplementation on growth performance, meat quality, blood biochemical parameters, and fecal microflora of finishing pigs. Thirty-two crossbred pigs (Duroc × Landrance × Yorkshire) (66-day-old, 67.95±0.25 kg) were randomly allocated to two treatments and fed diets containing soybean meal and FSBM. The average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), blood biochemical parameters, and meat quality index were measured. At the end of experiment, the fecal microflora of finishing pigs was analyzed with 16S rDNA techniques. Results revealed that pigs fed FSBM had a greater ADG and lower cooking loss relative to control group (basal diets). Compared with the control group, the triglyceride content in the serum of the group fed FSBM increased significantly, and the creatinine content in the serum decreased notably. Fermented soybean meal enhanced the abundance of Bacteroidetes, Prevotellaceae, Bcteroidales, Bacteroidia, but inhibited the growth of Firmicutes, Clostridia, Clostridiales, and Ruminococcaceae in the intestine of pigs. Therefore, we can speculate that FSBM may play an important role in animal production. Dietary FSBM supplementation may be beneficial to some aspects of growth performance and the diversity of fecal microflora in finishing pigs.

Abstract MYD88 plays an important role in the immune response against infections. To analyze MYD88 gene expression during different stages of pig development, we used real-time PCR. MYD88 was seen expressed in all tissues examined. MYD88 expression in spleen, lungs, and thymus reached its highest value from 7 to 14 days of age and decreased thereafter. Expression in lymph nodes was high until 28 days of age and then it declined after weaning, with stable low levels in adult pigs. MYD88 expression was high before 35 days of age in the small intestine (duodenum, jejunum, and ileum), where it reached its highest value from 7 to 14 days of age. MYD88 expression in the small intestine declined post-weaning and remained relatively low during adulthood. The results of this study suggest that weaning stress and development of the immune system might be positively correlated with MYD88 expression regulation. Moreover, this study provided evidence that the high expression of MYD88 may diminish weaning stress and increase disease resistance in Meishan pigs.