Myoblast differentiation plays a vital role in skeletal muscle regeneration. However, the protein-coding genes controlling this process remain incompletely understood. Here, we showed that chloride intracellular channel 5 (CLIC5) exerts a critical role in mediating myogenesis and skeletal muscle regeneration. Deletion of CLIC5 in skeletal muscle leads to reduced muscle weight and decreases the number and differentiation potential of satellite cells. In vitro, CLIC5 consistently inhibits myoblast proliferation while promoting myotube formation. CLIC5 promotes myogenic differentiation by activating the canonical Wnt/β-catenin signaling pathway in a biglycan (BGN)-dependent manner. CLIC5 deletion impairs muscle regeneration. Paired box gene 7 (Pax7) expression and the activity of BGN-mediated canonical Wnt/β-catenin signaling are reduced in CLIC5-deficient mice. Conversely, increasing CLIC5 levels in skeletal muscles enhances muscle regeneration capacity. In conclusion, our findings underscore CLIC5 as a pivotal regulator of myogenesis and skeletal muscle regeneration, functioning through interaction with BGN to activate the canonical Wnt/β-catenin signaling pathway.

The study was conducted to evaluate effects of short-term or long-term administration of 25- hydroxyvitamin D3 [25(OH)VD3] on growth performance, bone characteristics, meat quality in growing pigs. A total of 144 pigs were allocated into three groups and fed diet contained 2000 IU vitamin D3 (VD3) or 25(OH)VD3 for a short-term and long-term administration. The results showed that long-term 25(OH)VD3 administration increased BW on d 56 and average daily gain in d 28–56. Furthermore, long-term feeding increased bone calcium content and mRNA expressions of calcium ion channel protein and anti-oxidases genes in the liver. In short, adding 25(OH)VD3 to the diet improved weight gain, bone characteristics, deposition of polyunsaturated fatty acids and antioxidant capacity compared with the VD3, while the long-term feeding of 25(OH)VD3 was particularly effective focusing on calcium deposition and mRNA expression of GPx1, Cu/Zn SOD and CaBP-D9K.

旨在研究日粮中添加L-苹果酸对断奶仔猪肠道健康和机体炎症反应的影响。本研究选取192头健康状况良好的28日龄三元杂交（杜×长×大）断奶仔猪[初始体重（9.12±0.52）kg]，随机分为4个处理，每个处理6个重复，每个重复8头猪（公母各半）。对照组饲喂玉米-豆粕型基础日粮，3个处理组分别在基础日粮中添加0.25%、0.5%和1%的L-苹果酸制品（含有20% L-苹果酸和80%载体），试验期28 d。分别在试验的第14和28天，前腔静脉采血制备血清，检测血清炎症因子水平，试验结束时屠宰测定仔猪空肠的炎症反应、抗氧化能力并观察空肠形态，分析与肠道黏膜屏障功能相关的蛋白表达水平。结果表明：1)与对照组相比，日粮添加1% L-苹果酸制品显著降低了试验第14天仔猪血浆中促炎因子肿瘤坏死因子-α（TNF-α）和白介素-6（IL-6）的水平（P＜0.01），显著升高了抗炎因子白介素-10（IL-10）的水平（P＜0.01）；显著降低了试验第28天血浆中IL-6的水平（P＜0.01），显著升高了IL-10的水平（P＜0.01）；这表明日粮添加1% L-苹果酸制品缓解了断奶仔猪的炎症反应。2)日粮中添加1%的L-苹果酸制品显著降低了空肠黏膜TNF-α、干扰素-γ（IFN-γ）和IL-6的水平（P＜0.05或P＜0.01），显著升高了IL-10的水平（P＜0.01）；同时，添加L-苹果酸制品显著升高了空肠黏膜中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH-Px）的活性（P＜0.05或P＜0.01），显著提高了总抗氧化能力（T-AOC）（P＜0.01），显著降低了丙二醛（MDA）的水平（P＜0.05）。3)添加L-苹果酸制品显著提高了空肠的绒毛高度（P＜0.01）以及绒毛高度与隐窝深度的比值（P＜0.05）。4)与对照组相比，L-苹果酸组空肠紧密连接蛋白中Occludin的蛋白表达水平有升高的趋势（P=0.07），Claudin-3的蛋白表达水平显著降低（P＜0.01）。综上所述，日粮中添加1% L-苹果酸制品可以改善断奶仔猪的抗炎能力，提高空肠的抗炎和抗氧化能力，改善消化吸收功能，进而起到改善肠道健康的作用，但是对肠道屏障功能的影响还需要进一步的研究。

本试验旨在研究日粮添加不同水平的2种复方中草药添加剂(加曼-100和料磺1号)对肉仔鸡生长性能、屠宰性能、免疫性能和组织病理学的影响,以评价2种复方中草药添加剂的效果和适宜添加量.试验一、二各选用432只1日龄AA肉仔鸡,随机分为4个处理,每个处理6个重复,每个重复18只鸡.试验一中4个处理组分别在基础日粮中添加0(对照组)、500、1000、1500 mg/kg加曼-100;试验二中4个处理组分别在基础日粮中添加0(对照组)、1500、2000、2500 mg/kg料磺1号,试验分前后两期(0～21 d、22～42 d)共42 d.结果表明:试验一中后期及全期时,与对照组相比,日粮添加加曼-100可提高肉仔鸡的平均日增重(P<0.01)并降低耗料增重比(P<0.01);1000 mg/kg加曼-100组提高了肉仔鸡屠宰率、全净膛率、腿肌率(P<0.01)和半净膛率(P<0.05),降低了腹脂率(P<0.01).试验二中,与对照组相比,日粮添加2000 mg/kg料磺1号可提高肉仔鸡后期及全期的平均日增重(P<0.05)并降低全期的耗料增重比(P<0.05);同时提高肉仔鸡屠宰率、半净膛率、全净膛率(P<0.01)和腿肌率(P<0.05).日粮添加加曼-100或料磺1号均提高了肉仔鸡血清免疫球蛋白水平(P<0.01),且各组间免疫器官指数均无显著差异,组织病理观察均无不良影响.综上,2种复方中草药添加剂可提高肉仔鸡生长性能、屠宰性能及免疫性能,加曼-100最适添加量为1000 mg/kg,料磺1号最适添加量为2000 mg/kg.

Background Long non-coding RNAs (lncRNAs) are emerging key regulators involved in a variety of biological processes such as cell differentiation and development. The balance between myogenesis and adipogenesis is crucial for skeletal muscle homeostasis in humans and meat quality in farm animals. The present study aimed to reveal the global transcriptomic profiles of adipogenic (Adi-) and myogenic (Myo-) precursors derived from porcine skeletal muscle and identify lncRNAs involved in the modulation of myogenesis homeostasis in porcine skeletal muscle. Results In this study, a total of 655 novel individual lncRNAs including differentially expressed 24 lncRNAs, and 755 differentially expressed mRNAs were identified (fold change ≥2 or ≤ 0.5 and adjusted P < 0.05). Integrated results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis accompanied by the variation of intracellular Ca 2+ concentration highlighted Lnc-ADAMTS9 involved in the modulation of myogenesis homeostasis in porcine skeletal muscle. Although Lnc-ADAMTS9 knock-down did not alter the mRNA expression of ADAMTS9, we demonstrated that Lnc-ADAMTS9 can promote myogenic proliferation and myogenic differentiation of myogenic precursors through inhibiting the ERK/MAPK signaling pathway. Conclusion We deciphered a comprehensive catalog of mRNAs and lncRNAs that might be involved in the regulation of myogenesis and adipogenesis homeostasis in the skeletal muscle of pigs. The Lnc-ADAMTS9 exerts an essential role in myogenesis through the ERK signaling pathway.

BACKGROUND:Skeletal muscle is a complex and heterogeneous tissue accounting for approximately 40% of body weight. Excessive ectopic lipid accumulation in the muscle fascicle would undermine the integrity of skeletal muscle in humans but endow muscle with marbling-related characteristics in farm animals. Therefore, the balance of myogenesis and adipogenesis is of great significance for skeletal muscle homeostasis. Significant DNA methylation occurs during myogenesis and adipogenesis; however, DNA methylation pattern of myogenic and adipogenic precursors derived from skeletal muscle remains unknown yet.METHODS:In this study, reduced representation bisulfite sequencing was performed to analyze genome-wide DNA methylation of adipogenic and myogenic precursors derived from the skeletal muscle of neonatal pigs. Integrated analysis of DNA methylation and transcription profiles was further conducted. Based on the results of pathway enrichment analysis, myogenic precursors were transfected with CACNA2D2-overexpression plasmids to explore the function of CACNA2D2 in myogenic differentiation.RESULTS:As a result, 11,361 differentially methylated regions mainly located in intergenic region and introns were identified. Furthermore, 153 genes with different DNA methylation and gene expression level between adipogenic and myogenic precursors were characterized. Subsequently, pathway enrichment analysis revealed that DNA methylation programing was involved in the regulation of adipogenic and myogenic differentiation potential through mediating the crosstalk among pathways including focal adhesion, regulation of actin cytoskeleton, MAPK signaling pathway, and calcium signaling pathway. In particular, we characterized a new role of CACNA2D2 in inhibiting myogenic differentiation by suppressing JNK/MAPK signaling pathway.CONCLUSIONS:This study depicted a comprehensive landmark of DNA methylome of skeletal muscle-derived myogenic and adipogenic precursors, highlighted the critical role of CACNA2D2 in regulating myogenic differentiation, and illustrated the possible regulatory ways of DNA methylation on cell fate commitment and skeletal muscle homeostasis.

Bisphenol A (BPA) is toxic to the reproductive and nervous system, even carcinogenetic in humans and animals. However, few studies focused on effects of BPA on the intestinal tract. Here, we detected BPA-induced injuries on intestinal mucosa and explored a reliable approach to counteract BPA effects. C57BL/6J mice were gavage BPA or BPA accompanied with ingestion of 4% (w/w) of glutamine for 4-wks. In vitro, IEC-6 cells were treated with 0.4 mmol/L BPA for 6 hours mimicking acute injury and 0.2 mmol/L BPA for 12 hours followed with or without the inclusion of 4 mmol/L glutamine for 12 hours to determine cell renewal, mitochondrial function and ROS-JNK/MAPK pathway upon moderate BPA exposure. As results, BPA exposure caused severe intestinal injury, and disturbed intestinal epithelial cell proliferation and apoptosis, accompanied with mitochondrial malfunction and activated JNK/MAPK pathway as well. Notably, glutathione metabolism was implicated in BPA-induce injury. Glutamine could well rescue cell renewal and mitochondrial function from BPA exposure-induced injuries. In conclusion, we demonstrated impaired effect of BPA exposure on intestinal functions, which could be well counteracted by glutamine partly via restoring mitochondrial function and normalizing ROS-JNK/MAPK pathway. Thereby, we provided a novel application of glutamine to rescue intestinal injury.

To investigate coordination of dietary levels of valine (Val) and isoleucine (Ile) on carcass traits and meat quality in pigs, 72 of 73.8 ± 1.6 kg crossbred barrows were randomly divided into a 2 (0.31% vs. 0.65% standard ileum digestible (SID) Val) × 2 (0.25% vs. 0.53% SID Ile) factorial arrangement. As a result, high dietary valine decreased myosin heavy-chain (MyHC)-I mRNA expression, pH24 h value, bound water amount (T21 peak area ratio), sarcoplasmic protein solubility and water holding capacity (WHC) of meat (P < .05). Meanwhile, high dietary isoleucine increased pH24 h value, sarcomere length (P < .05) and tend to decrease drip loss (P = .07). The significant interactions between valine and isoleucine were observed on backfat thickness, water distribution forms and myofibrillar protein solubility (P < .05) of pork. High valine diets undermined WHC of meat probably through decreasing pH24 h value and sarcoplasmic protein solubility considering their significant correlations with drip loss

This study is aimed at exploring the mechanism underlying the homeostasis between myogenesis and adipogenesis in skeletal muscle using a special porcine model with a distinct phenotype on muscle growth rate and intramuscular fat deposition. Differentiation potential of muscle-derived Myo-lineage cells of lean-type pigs was significantly enhanced relative to obese-type pigs, while that of their Adi-lineage cells was similar. Single-cell RNA sequencing revealed that lean-type pigs reserved a higher proportion of Myo-lineage cells in skeletal muscle relative to obese-type pigs. Besides, Myo-lineage cells of the lean-type pig settled closer to the original stage of muscle-derived progenitor cells. Proteomics analysis found that differentially expressed proteins between two sources of Myo-lineage cells are mainly involved in muscle development, cell proliferation and differentiation, ion homeostasis, apoptosis, and the MAPK signaling pathway. The regulation of intracellular ion homeostasis, Ca2+ in particular, significantly differed between two sources of Myo-lineage cells. Ca2+ concentration in both cytoplasm and endoplasmic reticulum was lower in Myo-lineage cells of lean-type pigs relative to obese-type pigs. In conclusion, a higher proportion and stronger differentiation capacity of Myo-lineage cells are the main causes for the higher capability of myogenic differentiation and lower intramuscular fat deposition. Relative low concentration of cellular Ca2+ is advantageous for Myo-lineage cells to keep a potent differentiation potential.

This study was aimed at evaluating the effects of activated charcoal-herb extractum complex (CHC) on antioxidant status, serum lipid metabolites and its safety supplement in weaning piglets. In experiment 1, a total of 216 piglets (Duroc × Landrace × Large White) weaned at 28 days of age with initial body weight of 8.55 ± 1.18 kg were assigned randomly to six treatment groups. each treatment group had six pens, with six pigs per pen. Pigs were fed a corn-soybean meal-based diet supplemented with 500, 1000, 1500 or 2000 mg kg−1 of CHC over two 14-d periods. Diets supplemented with 0 and 1000 mg kg−1 of montmorillonite (MMT) were set as the negative and positive controls, respectively. In experiment 2, pigs (n = 108) weaned at 28 days of age with initial body weight of 8.58 ± 0.04 kg were randomly assigned to three treatment groups. Each treatment group had six pens, with six pigs per pen. Pigs were fed a corn-soybean meal-based diet supplemented with 0, 1000 or 10,000 mg kg−1 of CHC over two 14-d periods. In experiment 1, on day 14, supplementation with CHC significantly decreased very low-density lipoprotein (VLDL) concentration while they decreased low-density lipoprotein (LDL) concentration on d 28, CHC at 500, 1000 or 1500 mg kg−1 significantly increase high-density lipoprotein (HDL) concentration. Supplementation with 500 or 1000 mg kg−1 CHC reduced serum malondialdehyde (MDA) concentration during the entire experimental period and increased the concentration of serum total superoxide dismutase (T-SOD) on d 14. CHC at 500 or 1000 mg kg−1 significantly reduced the liver MDA concentration and increased liver T-SOD concentration. In experiment 2, increased ADG was obvious during the first 14 days and the whole period in 1000 mg kg−1 supplemented pigs, similarly F: G was lowest in the first 14 days. There was no difference in growth performance, visceral index, haematological and serum biochemical parameters and visceral organs morphology between pigs fed 10,000 mg kg−1 of CHC and control. Together, 500 to 1000 mg kg−1 CHC was confirmed to improve antioxidant status, and serum lipid metabolites in this study and excess supplementation of CHC is safe in weaning piglets.

This study was conducted to evaluate the effects of activated charcoal-herb extractum complex (CHC) on the growth performance, immunological indices, intestinal morphology and microflora in weaning piglets to determine the optimal supplemental dose. A total of 216 weaned piglets (Duroc Landrace Large White) with an initial body weight of 8.55 1.18 kg were randomly assigned to six treatment groups; each treatment group had six pens, with six pigs per pen. The study period was 28 d. Pigs were fed a corn-soybean meal-based diet supplemented with 500, 1000, 1500 or 2000 mg kg 1 of CHC over two 14-d periods. Two additional diets containing 0 and 1000 mg kg 1 of montmorillonite were set as the negative and positive controls, respectively. Supplementation with 500 mg kg 1 of CHC significantly increased average daily gain compared with the positive and negative controls during phase I and the entire experimental period (P < 0.05). During phase I, 500 and 1000 mg kg 1 of CHC significantly decreased diarrhea incidence compared with the negative control, and increased serum IGF-1 and serum IgM levels compared with the controls (P < 0.05). CHC at 500 mg kg 1 significantly decreased the diarrhea score during the entire experimental period compared with the negative control (P < 0.05). On day 28, supplementation with 500 and 1000 mg kg 1 of CHC increased serum IgG, IL-1b, and duodenum and jejunum secretory IgA compared with the negative control and decreased duodenum and jejunum MDA levels compared with the controls (P < 0.05). Increased duodenum and jejunum villus height and an increased ratio of villus height to crypt depth were observed compared with the negative control and decreased viable counts of E. coli in the cecum were detected compared with the controls (P < 0.05). Collectively, the optimal dose of CHC was found to be 500 to 1000 mg kg 1 in this study.

The balance of myogenic and adipogenic differentiation is crucial for skeletal muscle homeostasis. Given the vital role of membrane proteins (MBPs) in cell signal perception, membrane proteomics was conducted to delineate mechanisms regulating differentiation of adipogenic and myogenic precursors in skeletal muscle. Adipogenic and myogenic precursors with divergent differentiation potential were isolated from the longissimus dorsi muscle of neonatal pigs by the preplate method. A total of 85 differentially expressed MBPs (P < 0.05 and fold change 1.2 or 0.83) between 2 precursors were detected via isobaric tags for relative and absolute quantitation (iTRAQ) assay, including 67 up-regulated and 18 down-regulated in myogenic precursors. Functional enrichment analysis uncovered that myogenic and adipogenic precursors showed significant differences in cytoskeleton organization, syncytium formation, environmental information processing, and organismal systems. Furthermore, key MBPs in regulating cell differentiation were also characterized, including ITGB3, ITGAV, ITPR3, and EPHA2. Noteworthily, EPHA2 was required for myogenic differentiation, and it may promote myogenic differentiation through ERK signaling. Collectively, our study provided an insight into the distinct MBP profile between myogenic and adipogenic precursors in skeletal muscle and served as a solid basis for supporting the role of MBPs in regulating differentiation.

The balance of adipogenic and myogenic differentiation of skeletal muscle-derived mesenchymal stem cells is particularly important in muscle development and intramuscular fat deposition. This study aimed to explore the differential regulation between adipogenic and myogenic precursors by comparative analysis of their global proteome expression profile. Adipogenic and myogenic precursors isolated from neonatal porcine longissimus dorsi muscle by the preplate method were verified for their unique and distinct differentiation potential under myogenic or adipogenic induction. A total of 433 differentially expressed proteins (DEP) ( P < 0.05 and FC > 1.20 or <0.83) between adipogenic and myogenic precursors were detected via a tandem mass tag (TMT)-coupled LC-MS/MS approach, including 339 up-regulated and 94 down-regulated proteins in myogenic precursors compared with adipogenic precursors. On the basis of functional annotation and enrichment analysis of 433 DEP, adipogenic and myogenic precursors showed significantly different metabolic pattern of energy substances and differential regulations of gene expression, cell structure and development, ion homeostasis, and cell motility and migration. Three pathways including PPAR signaling pathway, phosphatidylinositol signaling system, and autophagy signaling pathway, which was differentially regulated between adipogenic and myogenic precursors, was also discovered to play crucial roles in cell differentiation. In conclusion, these differentiated regulation patterns between the two cell subsets of mesenchymal precursors together defines their differentiation potential specificity.

SCOPE:Protein restriction (PR) is beneficial for relieving metabolic disorders and aging-related diseases. However, extreme PR could result in malnutrition due to severe deficiency of essential amino acids. Therefore, the effect of moderate PR on insulin sensitivity is investigated. METHODS AND RESULTS:The growing and adult pigs are subjected to moderate PR by 15-30%. Plasma insulin concentration and insulin resistance index HOMA-IR are significantly decreased upon moderate PR. Furthermore, IRS1/PI3K/AKT pathway in the basal state is enhanced in both liver and skeletal muscle. The adapted metabolism in the liver upon moderate PR is in support of improving insulin sensitivity. The liver shares a coordinated metabolic adaption in terms of energy metabolism and amino acid metabolism with the small intestine. Particularly, alteration of the metabolic footprint appeared in the portal venous blood, representing metabolites to be absorbed into liver after intestinal metabolism, is also in favor of improvement of insulin sensitivity. CONCLUSION:In summary, the study proves that moderate PR could improve insulin sensitivity from childhood to adulthood in a pig model, and sheds a new light on the role of integrated remodeling of gut and liver metabolism in the improved insulin sensitivity induced by moderate PR.