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Low-protein diet fed to crossbred sows during pregnancy and lactation enhances myostatin gene expression through epigenetic regulation in skeletal muscle of weaning piglets

Jia, Yimin, Gao, Guichao, Song, Haogang, Cai, Demin, Yang, Xiaojing, Zhao, Ruqian
European journal of nutrition 2016 v.55 no.3 pp. 1307-1314
Western blotting, average daily gain, body weight, chromatin, crossbreds, crude protein, epigenetics, gene activation, gene expression, genes, glucocorticoid receptors, growth retardation, histones, lactation, longissimus muscle, low protein diet, males, maternal effect, messenger RNA, myostatin, piglets, precipitin tests, pregnancy, protein synthesis, reverse transcriptase polymerase chain reaction, skeletal muscle, sows, transcription (genetics), urea nitrogen, weaning
PURPOSE: This study was aimed to investigate the effects of a maternal low-protein diet on transcriptional regulation of the myostatin (MSTN) gene in skeletal muscle of weaning piglets. METHODS: Sows were fed either a standard-protein (SP, 15 and 18 % crude protein) or a low-protein (LP, 50 % protein level of SP) diet throughout pregnancy and lactation. Longissimus dorsi muscle was sampled from male piglets at 28 days of age. The mRNA was determined by RT-PCR, and protein was measured by Western blot. Chromatin immunoprecipitation assay was used to determine the binding of transcription factors and histone H3 modifications on the MSTN gene promoter. RESULTS: The maternal LP diet significantly decreased body weight and average daily gain (P < 0.05), which was associated with significantly lower plasma concentration of urea nitrogen and total protein (P < 0.05), as well as decreased muscle RNA content (P < 0.05). MSTN mRNA (P < 0.05) was significantly increased, together with enhanced (P < 0.05) mRNA and protein expression of forkhead box class O family member protein 3 (FoxO3), and a tendency of an increase (P = 0.10) in glucocorticoid receptor (GR) mRNA in the muscle of LP piglets. Furthermore, the binding of both FoxO3 and GR to the MSTN gene promoter was significantly higher (P < 0.05) in muscle of LP piglets, together with significantly enriched (P < 0.05) gene activation markers, H3K9Ac and H3K4me3. CONCLUSION: These results indicate that MSTN mediates maternal LP diet-induced growth retardation, through epigenetic regulation involving FoxO3 and GR binding to its promoter.