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Infection with transmissible gastroenteritis virus (TGEV) has been associated with villous atrophy within 48 h, which seriously disrupts intestinal homeostasis. However, the underlying mechanisms remain elusive. In this study, we found that TGEV infection severely disrupted intestinal homeostasis via inhibition of self-renewal and differentiation in Lgr5 intestinal stem cells (ISCs). Profoundly, TGEV-encoded NSP10/NSP16 protein complex-mediated the inactivation of Notch signaling provided a mechanistic explanation for this phenomenon. Initial invasions by TGEV-targeted Paneth cells through aminopeptidase N (APN) receptor, then inducing mitochondrial damage and ROS generation in them, ultimately causing Paneth cell decrease and loss of Notch factors (DII4 and Hes5), which are essential for Lgr5 ISCs self-renewal and differentiation. Interestingly, loss of Notch signaling induced goblet cells differentiation at the cost of absorptive enterocytes and promoted mucins secretion, which accelerated TGEV replication. Therefore, the more differentiation of goblet cells, the greater TGEV infection in jejunum. These results provide a detailed mechanistic pathway by which villous atrophy sharply occurs in TGEV-infected jejunum within 48 h. Thus, the pathogenesis of TGEV can be described as a “bottom up scenario”, which is contrary to the traditional “top down” hypothesis. Together, our findings provide a potential link between diarrheal virus infection and crypt cells response that regulates Paneth cells function and Lgr5 ISCs fate and could be exploited for therapeutic application.

Worldwide, antibacterial resistance has increased dramatically in the past years. Antimicrobial peptides are a group of immune-related peptides/proteins that protect the host from microbial infections, and were identified broad activity against pathogenic microorganism and not easy to generate insecticide resistance. It appears that antimicrobial peptides possess great potential for developing into a new ideal antimicrobial drug. Bombyx mori Gloverin A2 (BMGlvA2) was an antimicrobial peptide of B. mori, however, directly extracted and purified BMGlvA2 was difficult and uneconomic. In this study, BMGlvA2 gene was successfully cloned from B. mori and heterologous expression with vector pET28a (+) by E. coli Rosetta (DE3). The selected E. coli Rosetta (DE3)-BMGlvA2 strain yielded 241 µg/ml recombinant BMGlvA2 (rBMGlvA2) protein after 9 h inducted by 1.0 mM IPTG (isopropyl-β-d-thiogalactoside) at 28 °C. rBMGlvA2 protein was identified by western blot and MALDI-TOF. MALDI-TOF analysis indicated that its amino acid sequence is consistent with naturally secreted proteins by B. mori (sequence coverage 78.71%). Importantly, inhibition zone assay shown that rBMGlvA2 efficiently inhibited the growth of several Gram-negative bacteria, including E. coli DH5α, E. coli Rosetta, E. coli K88, S. typhimurium and several Gram-positive bacteria, including S. aureus and B. subtilis. Furthermore, The MIC of rBMGlvA2 showed antimicrobial activity against E. coli DH5α. Meaningfully, rBMGlvA2 did not display hemolytic activity against pig red blood cells. In conclusions, the antimicrobial activity and hemolytic of rBMGlvA2 suggested that it could be one of potential alternatives to conventional antibiotics against Gram-negative and Gram-positive bacteria.

Maternal undernutrition during gestation influences the development of the fetus, thereby increasing the risk of metabolic syndrome in adulthood. Skeletal muscle, one of the key insulin-responsive organs, is susceptible to maternal nutritional programming. This study aimed to evaluate the effect of moderate maternal energy restriction during gestation in pigs on basic events of fetal skeletal myogenesis. Primiparous, purebred Meishan sows were fed a control (normal energy intake) or a low-energy (LE) diet from mating to day 90 of gestation. Biochemical characteristics, myogenic gene expression, and myofiber characteristics were assessed in longissimus dorsi (LD) muscle of fetuses on days 55 and 90 of gestation. Fetal weights, myofiber density, and fetal umbilical vein serum triiodothyronine (T3) concentration decreased in LE group on both days 55 and 90 of gestation. The expression and activity of creatine kinase, the messenger RNA (mRNA) expression of myosin heavy chain ( MYH/ MyHC) genes ( MYH2 and MYH4), concentration of muscular DNA and protein, and protein expression of fast-MyHC isoforms were reduced in LD muscle of LE fetuses on day 55 or 90 of gestation. Meanwhile, myogenic gene expression was reduced in LE fetuses on day 55 or 90 of gestation, indicating the downregulation of myogenesis. Additionally, the exposure to LE diet led to increased isocitrate dehydrogenase activity and slow MyHC (MYH7) mRNA expression on day 90 of gestation, suggesting the elevation of oxidative muscle metabolism. These findings suggest that moderate energy restriction during gestation attenuates fetal skeletal muscle development in pigs, resulting in the delay of skeletal muscle differentiation and maturity.

Background Alginate oligosaccharide (AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function, as well as epithelium apoptosis. Methods Twenty-four weaned pigs were distributed into two groups (n = 12) and received either a basal diet (control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose (0.1 g/kg body weight) was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later. Results Our results showed that inclusion of AOS in the diet for 2 wk increased (P

Background Pea fiber (PF) is a potential fibrous supplement in swine production. The influence of dietary PF on microbial community in the colon of pigs remains largely unexplored. Methanogens in the hindgut of monogastric animals play important roles in degradation of dietary fibers and efficient removal of microbial metabolic end product H2. Understanding the impact of dietary PF on the structure of colonic methanogens may help understand the mechanisms of microbe-mediated physiological functions of PF. This study investigated the influence of PF on the diversity and quantity and/or activity of colonic methanongens of piglets and finishing pigs. Four archaeal 16S rRNA clone libraries were constructed for piglets and finishers fed with control (Piglet-C and Finisher-C) or PF diet (Piglet-P and Finisher-P). Results There were 195, 190, 194 and 196 clones obtained from the library Piglet-C, Piglet-P, Finisher-C and Finisher-P, respectively, with corresponding 12, 11, 11 and 16 OTUs (operational taxonomic units). Significant differences of Shannon Index among the four libraries were found (P

The objective of this study was to investigate the effects of free amino acids supplementation to protein restricted diet on the intestinal morphology and proteome composition in weaning pigs. Weanling piglets were randomly fed one of the three diets including a corn-soybean based control diet and two lower protein diets with or without free amino acids supplementation for 2 weeks. The jejunum samples of piglets were collected for morphology and proteome analysis. Compared with the control diet, the protein restricted diet had a significant lower average daily gain and higher feed conversion rate. Free amino acids supplementation to the protein restricted diet significantly improved average daily gain and higher feed conversion rate, compared with the protein restricted diet. The villous height in pigs fed the protein restricted diet was lower than that of the control and free amino acids diet. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 16 differentially expressed protein spots in the jejunum of the weaning piglet. These proteins were related to stress and immune response, the metabolism of carbohydrates and lipids, and tissue structure. Based on the proteome and ELISA analysis, free amino acids diet significantly down-regulated the jejunal expression of stress protein heat shock 60 kDa protein. Our results indicated that amino acids supplementation to the protein restricted diet could enhance weight gain and feed efficiency in weanling pigs through improving intestinal nutrient absorption and transportation, gut health, and mucosal immunity.

Background The present study was conducted to compare the differences in gut microbiota composition and gut-phenotypes among pig breeds, and determine whether these differences would transmit to mice colonized with fecal microbiota of different pig breeds. A total of 24 1-day-old germ-free BALB/C mice were divided into 3 groups (TFM, YFM and RFM), which were transplanted with intact fecal microbiota of Tibetan pig (TP), Yorkshire pig (YP) and Rongchang pig (RP), respectively. Results Results showed that different pig breeds exhibited distinct gut microbiota profile based on high-throughput pyrosequencing. YP exhibited a lower Firmicutes/Bacteroidetes ratio and apparent genera differences compared with RP and TP, and higher levels of bacteria from Spirochaetes were observed in TP compared with RP and YP (P

Background Mitochondria are of major importance in oocyte and early embryo, playing a key role in maintaining energy homeostasis. Epidemiological findings indicate that maternal undernutrition-induced mitochondrial dysfunction during pregnancy is associated with the development of metabolic disorders in offspring. Here, we investigated the effects of moderately decreased maternal energy intake during pregnancy on skeletal muscle mitochondrial biogenesis in fetal offspring with pig as a model. Methods Pregnant Meishan sows were allocated to a standard-energy (SE) intake group as recommended by the National Research Council (NRC; 2012) and a low-energy (LE) intake group. Fetal umbilical vein serum and longissimus muscle samples were collected for further analysis on day 90 of pregnancy. Results Sow and fetal weights and the concentrations of serum growth hormone (GH) and glucose were reduced in LE group. Maternal LE diet decreased the messenger RNA (mRNA) expression of genes involved in mitochondrial biogenesis and function such as peroxisome proliferator-activated receptor gamma coactivator 1α (PPARGC1A), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), β subunit of mitochondrial H+-ATP synthase (ATB5B), sirtuin 1 (Sirt1), and citrate synthase (CS). The protein expression of PPARGC1A and Sirt1, intracellular NAD+-to-NADH ratio, and CS activity was reduced in LE group, and accordingly, mitochondrial DNA (mtDNA) content was decreased. Moreover, copper/zinc superoxide dismutase (CuZn-SOD) expression at both mRNA and protein levels and SOD and catalase (CAT) activities were reduced in LE group as well. Conclusions The observed decrease in muscle mitochondrial biogenesis and antioxidant defense capacity suggests that moderately decreased maternal energy intake during pregnancy impairs mitochondrial function in fetal pigs.

Background As a organic acid, benzoic acid has become one of the most important alternatives for antibiotics, and its beneficial effect on performance in animals has been proven for a decade. However, knowledge of the effects of benzoic acid on jejunal digestive physiology, especially the antioxidant capacity and mucosal glucagon-like peptide 2 (GLP-2) concentrations is lacking. Methods A total of 20 barrows [Duroc × (Yorkshire × Landrace)] with an average body weight (BW) of 18.75 ± 0.2 kg were used in a 14-d trial to determine the potential mechanisms of benzoic acid supplementation on the performance, nutrient digestibility and jejunal digestive physiology in young pigs. All pigs were randomly allotted to 1 of 2 diets supplemented with 0 or 5000 mg/kg benzoic acid. Results Relative to the control, benzoic acid supplementation increased the average daily feed intake (ADFI), and average daily gain (ADG) in young pigs (P

Recently, increasing evidence supports that adult stem cells are the part of a natural system for tissue growth and repair. This study focused on the differences of mesenchymal stem cells from adult adipose (ADSCs), skeletal muscle (MDSCs) and fetal muscle (FMSCs) in biological characteristics, which is the key to cell therapy success. Stem cell antigen 1 (Sca-1) expression of MDSCs and FMSCs at passage 3 was two times more than that at passage 1 (P

IFN-β promoter stimulator 1 (IPS-1) is an important adaptor protein linking RIG-I/MDA5 to the downstream signaling molecules and plays the pivotal role in type I interferons induction. In this study, we cloned and characterized Tibetan porcine IPS-1, investigated the tissue distribution, compared different messenger RNA expression for IPS-1 between Tibetan and Crossbred (Duroc × Yorkshire × Landrace) pigs (DLY). The Tibetan porcine IPS-1 gene was first cloned from spleen. The entire open reading frame (ORF) of the IPS-1 is 1,575 bp and encodes for 524 amino acid residues, has 1 putative transmembrane domains, with a higher degree of sequence similarity with common pig (99.37%) and cattle (81.23%) than with human (70.20%) or mouse (63.44%). Real-time quantitative PCR analysis indicated that Tibetan porcine IPS-1 mRNA was most abundant in the liver and kidney. The expression of IPS-1 of Tibetan pigs in most tissues was higher than DLY pigs.

Intrauterine growth retardation (IUGR) induces alterations to hepatic gene expressions which might program poor postnatal growth and health status. Maternal folic acid supplementation was administered in gilt diets to test whether hepatic mRNA expressions of some important genes induced by IUGR could be rescued by folic acid supplementation. Thirty-two Yorkshire gilts were allotted to two treatment groups of control (C folic acid 1.3 mg/kg) or folic acid supplementation (FS folic acid 30 mg/kg) after mating, to study the effects of maternal folic acid supplementation on the mRNA expression of methionine adenosyltransferase (MAT), cystathionine-β-synthase (CBS), methylenetetrahydrofolate reductase (MTHFR), DNA methyltransferase1 (DNMT1), peroxisomal proliferator-activated receptor (PPARγ), glucocorticoid receptor (GR), obesity receptor (ob-R) and Acyl-CoA oxidase (AOX) in the liver of IUGR and NBW piglets. Blood and liver samples were collected for determinations of serum folic acid and gene expressions. The total number of born piglets, number of piglets born alive, average birth weight and 21 days average weight were not affected by dietary treatment (P > 0.05), and serum folic acid concentration of piglets was greater in FS than C groups (P < 0.05). Real-time PCR indicated that gene expression of MAT1A, MAT2A and DNMT1 were lower in IUGR piglets but could be elevated by maternal folic acid supplementation. Transcript expression levels of PPARγ, GR and AOX were higher in IUGR piglets, but were decreased to the level of normal piglets by maternal folic acid supplementation. Our results suggested that maternal folic acid supplementation be an effective way to rescue the gene expressions negatively induced by IUGR.

Leptin plays a critical role in regulating muscle protein metabolism by binding with leptin receptors in a 1:1 stoichiometry. However, the role for leucine in the regulation of leptin receptor expression in muscle has not been investigated. The present study was conducted to test the hypothesis that leucine regulates leptin receptor levels in C2C12 myotubes. Cells were cultured in the presence of DMEM/F12 medium containing supplemental 0 or 5 mM L: -leucine. Leptin receptor expression by C2C12 myotubes peaked at 2 h post-supplementation. Additionally, leucine stimulated leptin receptor expression at both mRNA and protein levels in a dose-dependent manner. Furthermore, leucine enhanced the phosphorylation of mammalian target of rapamycin (mTOR). Addition of rapamycin (an inhibitor of mTOR) to culture medium completely suppressed leucine-induced activation of mTOR and inhibited leucine-stimulated leptin receptor production. These results indicate that leucine affects leptin receptor expression in muscle cells via the mTOR signaling pathway.

Oxidative stress can induce abnormal tryptophan metabolism. The present study was mainly conducted to determine the effect of dietary tryptophan levels on oxidative stress in the liver of weaned pigs challenged by diquat. A total of 36 PIC piglets weaned at 21 days of age were randomly allotted to 1 of 3 diets containing dietary tryptophan levels of 0.18, 0.30, and 0.45% for 14 d. On day 8, the piglets were injected intraperitoneally with sterile 0.9% NaCl solution or diquat (10 mg/kg body weight). During the first 7 d of trial, increasing dietary tryptophan levels enhanced average daily gain (P = 0.09) and average daily feed intake (P = 0.08), and decreased the feed efficiency (P P P P P P = 0.09) and tryptophan 2,3-dioxygenase (TDO) activity (P = 0.07) in liver of piglets. Increasing dietary tryptophan levels could attenuate the effects of diquat injection on the MDA (P = 0.06) concentration and the activities of SOD (P = 0.09) and GPx (P = 0.05) of the liver, and plasma urea nitrogen (P = 0.06) concentration in the piglet. There was a synergistic role for increasing TDO activity in the liver between dietary tryptophan levels and diquat injection (P