The present study was conducted to investigate effects of Bacillus subtilis on growth performance, serum parameters, digestive enzymes, intestinal morphology, and colonic microbiota in piglets. A total of 72 piglets were weighed and randomly allotted into three treatments (four replication pens per treatment with six piglets/pen) for a 28-day experiment. The dietary treatments were as follows: basal diet (control group, CTR), basal diet supplementation with antibiotic (antibiotic group, ABT), and basal diet supplementation with 0.1% Bacillus subtilis (probiotic group, PBT). The average daily gain of body weight increased in both the ABT and PBT groups, and dietary antibiotics decreased the feed:gain ratio (F:G), as compared to the CTR group (P < 0.05). Both ABT and PBT piglets had increased serum triglycerides and lipase, amylase, maltase activities and villus height:crypt depth ratio (V/C) in ileum (P < 0.05). The PBT group also showed an increase in serum glucose and villus height in the ileum (P < 0.05). Dietary antibiotics increased Lactobacillus johnsonii, as compared to the CTR group, but decreased bacterial diversity and increased Escherichia coli, as compared to the PBT group (P < 0.05). Piglets dietary with B. subtilis modulated the microbiota by increasing the abundance of Firmicutes (L. johnsonii, L. reuteri) and decreasing the abundance of E. coli, as compared to the control group (P < 0.05). These results indicate that dietary of B. subtilis improves growth performance and intestinal health and can be a promising alternative to antibiotics in piglets diet.

The Chinese believe that the meat of pigs reared in the past with free range tastes better than that of the pigs reared indoor on a large scale today. Gastrointestinal microflora is closely associated with the main factor of meat flavour, including fibre characteristics and lipid metabolism. Our method in this study involved different raising patterns within the semi free-grazing farm (FF) or indoor feeding farm (DF), the measurement of fat deposition and myofiber type by paraffin section and reverse transcription polymerase chain reaction and the identification of microbiome and functional capacities associated with meat quality through metagenomic sequencing. Results showed that the fat area in muscle and adipose tissue and the myofiber density significantly increased in the pigs of the FF group. The relative abundance of bacteria associated with lipid metabolism, such as g_Oscillibacter, in the feces of the FF group was higher than that in DF group, and the relative abundance of some bacteria with probiotic function, including g_Lactobacillus and g_Clostridium, was lower than that in DF group. The abundance of g_Clostridium was significantly positively correlated with the intramuscular fat area, whereas health-related bacteria, such as g_Butyricicoccus, g_Eubacterium, g_Phascolarctobacterium and g_Oribacterium, was significantly negatively correlated with abdominal fat area, myofiber density and adipose triglyceride lipase (ATGL) mRNA expression. KEGG analysis showed that pigs raised in semi free-grazing farm can activate the pathway of inosine monophosphate (IMP) biosynthesis, glycolysis/gluconeogenesis and alanine, aspartate and glutamate metabolism. Free range feeding improves meat quality by changing the fibre type, myofiber density and metabolic pathways related to flavour amino acids, IMP or glycolysis/gluconeogenesis in muscle. However, prolonged feeding cycle increases fat deposition and associated microbial communities.

Background: Irisin (a glycosylated protein) is cleaved from fibronectin type III domain-containing protein 5 (FNDC5), which is expressed mainly in animal muscle tissues and has multiple metabolic regulatory activities. However, their roles in controlling myofiber types in skeletal muscle remain unclear. Methodology: Two different commercial hybridized pigs, LJH (a crossed pig containing Chinese native pig genotypes) and DLY (Duroc × Landrace × Yorkshire) were selected to analyze FNDC5 mRNA expression and the mRNA composition of four adult myosin heavy chain (MyHC) isoforms (IIIaIIxIIb) in the longissimus dorsi (LD) muscle. C2C12 myoblasts were cultured to investigate the effects of FNDC5 on the four MyHCs mRNA expressive levels, using small interfering RNA for depletion and a eukaryotic expression vector carrying FNDC5 for overexpression. ZLN005 (a small molecule activator of FNDC5’s upstream control gene PGC1α) or recombinant human irisin protein were also used. Results: In LD muscle, LJH pigs had the higher FNDC5 mRNA level, and MyHC I or IIa proportion than DLY pigs (P <  0.05). For C2C12 cells in vitro, small interfering RNA (si-592) silencing of FNDC5 expression markedly reduced MyHC IIa mRNA levels (P <  0.05), while FNDC5 overexpression significantly increased MyHC IIa mRNA levels (P <  0.05). Exogenous irisin increased the mRNA levels of PGC1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha), FNDC5, MyHCI, MyHCIIa, NRF1 (nuclear respiratory factor 1), VEGF (vascular endothelial growth factor), and TFAM (mitochondrial transcription factor A,) (P <  0.05), and the enzyme activities of SDH (succinate dehydrogenase), CK (creatine kinase), and MDH (malate dehydrogenase) in C2C12 myotubes (P <  0.05). These results showed that FNDC5 mRNA expression had a significant association with the characteristics of myofiber types in porcine muscle, and participated in regulating MyHCs mRNA expression of C2C12 myogenic differentiation cells in vitro. FNDC5 could be an important factor to control muscle fiber types, which provides a new direction to investigate pork quality via muscle fiber characteristics.

Glucagon-like peptide-2 (GLP-2) is an intestinal hormone that promotes intestinal growth, but the rapid degradation by dipeptidyl peptidase-IV limits its applications. PLGA microsphere is a well-developed drug delivery system, while seldom been studied as a solution for prolonging in vivo effects of GLP-2. In this study, we encapsulated porcine GLP-2 (pGLP-2) into microspheres and investigated its therapeutic effects in dextran sulfate sodium (DSS)-treated mice. pGLP-2 microspheres showed 20.36% in initial burst and constant release for at least 9 d. In the DSS-treated mice, a single injection of GLP-2 microspheres significantly increased the body weight, colonic length, small intestinal weight and mRNA expression of Occludin, decreased the colonic damage score, mRNA expression of IL-6, IL-10, TNF-α and IFN-γ. In conclusion, pGLP-2 microspheres were resistant to degradation and decreased the severity of DSS-induced ulcerative colitis which suggested that GLP-2-loaded microspheres could be a proper candidate for the treatment of ulcerative colitis.