Maternal low-protein diet affects myostatin signaling and protein synthesis in skeletal muscle of offspring piglets at weaning stage.

Purpose: 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. [ABSTRACT FROM AUTHOR]