PSIII-23 Maternal metabolizable protein level and rumen-protected methionine impacts on beef steer progeny gene expression in muscle and liver

This experiment evaluated how maternal metabolizable protein level and rumen-protected methionine supplementation during late gestation impacts expression of genes associated with fetal programming in beef steer offspring. In a 3 x 2 factorial arrangement, 138 Angus crossbred cows were randomly assigned one of three metabolizable protein (MP) treatments (fed to meet 90, 100, or 110% of MP requirements), with(without) 9 g/d of rumen-protected methionine (MET; Smartamine®M, Adisseo Inc.). The isocaloric diets were fed for the last 8 weeks of gestation. Steer progeny (n = 51) were assigned to one of seven pens by weight and received a common corn-based grower diet (58% corn silage, 26% alfalfa haylage, 15% soybean meal) for 47 days, followed by a finisher diet (78% high moisture corn, 12% alfalfa haylage, 8% soybean meal) for 115 ±31.5 days until slaughter. At slaughter, samples of Sternomandibularis muscle and liver were collected and snap-frozen in liquid nitrogen for RNA isolation and analysis of gene expression for growth, myogenic, and adipogenic genes. Data were analyzed using PROC GLIMMIX in SAS, with maternal MP level and MET supplementation as fixed effects, and pen as a random effect. Exceeding maternal MP requirements increased expression of myogenic regulatory factor, myogenin (MYOG; 90% MP: 0.72, 100% MP: 0.94, and 110% MP: 1.00; SEM = 0.083, respectively; P = 0.02) in muscle from steer progeny at slaughter. Methionine supplementation decreased expression of pyruvate kinase (PKM; MET: 0.81, No MET: 1.16; SEM = 0.092; P = 0.02) in muscle, which is associated with lean tissue growth. Maternal nutritional treatment did not influence hepatic gene expression (P ≥ 0.06). These data suggest that maternal nutrition may impact progeny muscle development, while maintaining metabolic function of the liver.

Key Genes Regulating Skeletal Muscle Development and Growth in Farm Animals

Farm-animal species play crucial roles in satisfying demands for meat on a global scale, and they are genetically being developed to enhance the efficiency of meat production. In particular, one of the important breeders’ aims is to increase skeletal muscle growth in farm animals. The enhancement of muscle development and growth is crucial to meet consumers’ demands regarding meat quality. Fetal skeletal muscle development involves myogenesis (with myoblast proliferation, differentiation, and fusion), fibrogenesis, and adipogenesis. Typically, myogenesis is regulated by a convoluted network of intrinsic and extrinsic factors monitored by myogenic regulatory factor genes in two or three phases, as well as genes that code for kinases. Marker-assisted selection relies on candidate genes related positively or negatively to muscle development and can be a strong supplement to classical selection strategies in farm animals. This comprehensive review covers important (candidate) genes that regulate muscle development and growth in farm animals (cattle, sheep, chicken, and pig). The identification of these genes is an important step toward the goal of increasing meat yields and improves meat quality.

Ciglitazone Increases Adiponectin and Adipogenic Gene Expression in Bovine Skeletal Muscle Satellite Cells

Background: Ciglitazone is a member of the thiazolidinedione (TZD) family, and specifically binds to peroxisome proliferator-activated receptor-γ (PPARγ) , thereby promoting adipocyte differentiation. We hypothesized that ciglitazone as a PPARγ ligand in the absence of an adipocyte differentiation cocktail would increase adiponectin and adipogenic gene expression in bovine satellite cells (BSC).Methods: Muscle-derived bovine satellite cells were isolated from six, 18-month-old Yanbian Yellow Cattle. The BSC were cultured for 96 h in differentiation medium containing 5 µM ciglitazone (CL), 10 µM ciglitazone (CM), or 20 µM ciglitazone (CH). Control (CON) BSC were cultured only in differentiation medium (containing 2% horse serum).Results: The presence of myogenin, desmin, and paired box 7 (Pax7) proteins were confirmed in the BSC by immunofluorescence staining. The CL, CM, and CH treatments produced higher concentrations of triacylglycerol and lipid droplet accumulation in myotubes than those of the CON treatment. Ciglitazone treatments significantly increased the relative expression of PPARγ , CCAAT/enhancer-binding protein alpha (C/EBPα), C/EBPβ, fatty acid synthase stearoyl-CoA desaturase (SCD) and perilipin 2. Ciglitazone treatments increased gene expression of paired box 3 (Pax3) and Pax7 and decreased expression of myogenic differentiation-1, myogenin, myogenic regulatory factor-5 (MRF5), and MYF4 (P < 0.01). Adiponectin concentration caused by ciglitazone treatments was significantly greater than CON (P < 0.01). RNA sequencing showed that 281 differentially expressed genes (DEGs) were found in the treatments of ciglitazone. DEGs gene ontology (GO) analysis showed that the top 10 GO enrichment significantly changed the biological processes such as protein trimerization, negative regulation of cell proliferation, adipocytes differentiation, and cellular response to external stimulus. KEGG pathway analysis showed that DEGs were involved into p53 signaling pathway, PPAR signaling pathway, biosynthesis of amino acids, TNF signaling pathway, non-alcoholic fatty liver disease (NAFLD), PI3K-Akt signaling pathway, and Wnt signaling pathway.Conclusion: These results indicate that ciglitazone acts as PPARγ agonist, effectively increasing the adiponectin concentration and adipogenic gene expression, and stimulating the conversion of BSC to adipocyte-like cells in the absence of adipocyte differentiation cocktail.

367 Role of skeletal muscle satellite cells in the broiler chicken Wooden Breast myopathy

To meet the huge global demand for chicken meat, the commercial broiler industry has placed tremendous genetic selection pressure on breast meat yield, growth rate, and feed efficiency traits and has made remarkable improvements over the last 30 years. Unfortunately, along with those tremendous improvements has come a severe meat quality defect whose cause has yet to be elucidated. The Wooden (or Woody) Breast (WB) meat quality defect is characterized by visible bulging of the breast fillet with extreme hardness to the touch. The WB phenotype has been characterized by histopathologists as a degenerative myopathy in which excessive fibrotic tissue infiltration occurs. Skeletal muscle stem cells, also called satellite cells (MSC), play a critical role in post-hatch broiler skeletal muscle growth, repair, and maintenance. Yet the relationship between MSC function in high-yielding broilers and the development of the WB myopathy is still not well understood. Recent work using in vivo cell labeling, cryohistology, and immunofluorescence techniques demonstrates that the relative size and mitotic activity of the various MSC and macrophage populations and collagen deposition are altered in WB-affected muscle. Alterations in myogenic regulatory factor, collagen, and pro- and anti-inflammatory cytokine protein expression in WB-affected muscles have also been observed using quantitative fluorescent Western blotting. These data suggest the involvement of aberrant MSC function in the development of WB myopathy. Future work aimed at determining whether the apparent MSC dysfunction in WB-affected broilers is due to an issue with the MSC themselves and/or their environment will be accomplished using a combination of MSC isolation, labeling, transplant, and tracking strategies. Further exploration will also be required to understand how the local cell signaling mechanisms and cell population kinetics are related to the severity and timing of the development of the WB myopathy in today’s fast-growing, high-yielding broilers.

Effects of mineral methionine hydroxy analog chelate in sow diets on epigenetic modification and growth of progeny

The study was conducted to determine the effects of mineral methionine hydroxy analog chelate (MMHAC) partially replacing inorganic trace minerals in sow diets on epigenetic and transcriptional changes in the muscle and jejunum of progeny. The MMHAC is zinc (Zn), manganese (Mn), and copper (Cu) chelated with methionine hydroxy analog (Zn-, Mn-, and Cu-methionine hydroxy analog chelate [MHAC]). On day 35 of gestation, 60 pregnant sows were allotted to two dietary treatments in a randomized completed block design using parity as a block: 1) ITM: inorganic trace minerals with zinc sulfate (ZnSO4), manganese oxide (MnO), and copper sulfate (CuSO4) and 2) CTM: 50% of ITM was replaced with MMHAC (MINTREX trace minerals, Novus International Inc., St Charles, MO). Gestation and lactation diets were formulated to meet or exceed NRC requirements. On days 1 and 18 of lactation, milk samples from 16 sows per treatment were collected to measure immunoglobulins (immunoglobulin G, immunoglobulin A, and immunoglobulin M) and micromineral concentrations. Two pigs per litter were selected to collect blood to measure the concentration of immunoglobulins in the serum, and then euthanized to collect jejunal mucosa, jejunum tissues, and longissimus muscle to measure global deoxyribonucleic acid methylation, histone acetylation, cytokines, and jejunal histomorphology at birth and day 18 of lactation. Data were analyzed using Proc MIXED of SAS. Supplementation of MMHAC tended to decrease (P = 0.059) body weight (BW) loss of sows during lactation and tended to increase (P = 0.098) piglet BW on day 18 of lactation. Supplementation of MMHAC increased (P &lt; 0.05) global histone acetylation and tended to decrease myogenic regulatory factor 4 messenger ribonucleic acid (mRNA; P = 0.068) and delta 4-desaturase sphingolipid1 (DEGS1) mRNA (P = 0.086) in longissimus muscle of piglets at birth. Supplementation of MMHAC decreased (P &lt; 0.05) nuclear factor kappa B mRNA in the jejunum and DEGS1 mRNA in longissimus muscle and tended to decrease mucin-2 (MUC2) mRNA (P = 0.057) and transforming growth factor-beta 1 (TGF-β1) mRNA (P = 0.057) in the jejunum of piglets on day 18 of lactation. There were, however, no changes in the amounts of tumor necrosis factor-alpha, interleukin-8, TGF-β, MUC2, and myogenic factor 6 in the tissues by MMHAC. In conclusion, maternal supplementation of MMHAC could contribute to histone acetylation and programming in the fetus, which potentially regulates intestinal health and skeletal muscle development of piglets at birth and weaning, possibly leading to enhanced growth of their piglets.