title: Maternal low-protein diet affects myostatin signaling and protein synthesis in skeletal muscle of offspring piglets at weaning stage.
abstract: OBJECTIVE
  We tested the hypothesis that maternal low-protein (LP) diet during gestation and lactation can program myostatin (MSTN) signaling and protein synthesis in skeletal muscle of offspring at weaning stage (35 days).
  
  
  METHODS
  Fourteen Meishan sows were fed either LP or standard-protein diets throughout gestation and lactation, male offspring piglets were killed at weaning stage and longissimus dorsi (LD) muscles were taken. The cross-sectional areas (CSA) of LD muscles were measured by hematoxylin and eosin staining. The levels of free amino acids in plasma were measured by amino acid auto-analyzer. Proteins and mRNA were determined by Western blot and RT-qPCR, respectively.
  
  
  RESULTS
  Body weight, LD muscle weight and the myofiber CSA were significantly decreased (P < 0.05) in LP piglets; meanwhile, the concentration of branched-chain amino acids was also significantly decreased (P < 0.001). MSTN protein content tended to be higher (P = 0.098) in LP piglets, while the expression of MSTN receptors, activin type II receptor-beta and transforming growth factor type-beta type I receptor kinase, was significantly up-regulated (P < 0.05). Furthermore, p38 mitogen-activated protein kinase, the downstream signaling factor of MSTN, was also enhanced significantly (P < 0.05). In addition, key factors of translation initiation, phosphorylated eukaryotic initiation factor 4E and the 70 kDa ribosomal protein S6 kinase, were significantly decreased (P < 0.05) in LP piglets.
  
  
  CONCLUSIONS
  Our results suggest that maternal LP diet during gestation and lactation affects MSTN signaling and protein synthesis in skeletal muscle of offspring at weaning stage.
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Liu
authors.forename: Shifeng
authors.initials: S
authors.lastname: Pan
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.forename: Qinwei
authors.initials: Q
authors.lastname: Sun
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Yang
authors.forename: Ruqian
authors.initials: R
authors.lastname: Zhao
mesh_terms: D000596:Amino Acids / Q000097:blood; D000597:Amino Acids, Branched-Chain / Q000097:blood; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D018753:Diet, Protein-Restricted / Q000009:adverse effects*; D039561:Eukaryotic Initiation Factor-4E / Q000032:analysis; D005260:Female; D007774:Lactation; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000254:growth & development; D055435:Myostatin / Q000378:metabolism*; D009929:Organ Size; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000032:analysis; D015398:Signal Transduction; D034421:Sus scrofa; D014886:Weaning
chemical_list: D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D039561:Eukaryotic Initiation Factor-4E; D009124:Muscle Proteins; D055435:Myostatin; D038762:Ribosomal Protein S6 Kinases, 70-kDa