title: The effect of hyperammonemia on myostatin and myogenic regulatory factor gene expression in broiler embryos.
abstract: Myogenesis is facilitated by four myogenic regulatory factors and is significantly inhibited by myostatin. The objective of the current study was to examine embryonic gene regulation of myostatin/myogenic regulatory factors, and subsequent manipulations of protein synthesis, in broiler embryos under induced hyperammonemia. Broiler eggs were injected with ammonium acetate solution four times over 48 h beginning on either embryonic day (ED) 15 or 17. Serum ammonia concentration was significantly higher (P<0.05) in ammonium acetate injected embryos for both ED17 and ED19 collected samples when compared with sham-injected controls. Expression of mRNA, extracted from pectoralis major of experimental and control embryos, was measured using real-time quantitative PCR for myostatin, myogenic regulatory factors myogenic factor 5, myogenic determination factor 1, myogenin, myogenic regulatory factor 4 and paired box 7. A significantly lower (P<0.01) myostatin expression was accompanied by a higher serum ammonia concentration in both ED17 and ED19 collected samples. Myogenic factor 5 expression was higher (P<0.05) in ED17 collected samples administered ammonium acetate. In both ED17 and ED19 collected samples, myogenic regulatory factor 4 was lower (P⩽0.05) in ammonium acetate injected embryos. No significant difference was seen in myogenic determination factor 1, myogenin or paired box 7 expression between treatment groups for either age of sample collection. In addition, there was no significant difference in BrdU staining of histological samples taken from treated and control embryos. Myostatin protein levels were evaluated by Western blot analysis, and also showed lower myostatin expression (P<0.05). Overall, it appears possible to inhibit myostatin expression through hyperammonemia, which is expected to have a positive effect on embryonic myogenesis and postnatal muscle growth.
authors.affiliation: 1Prestage Department of Poultry Science,North Carolina State University,Raleigh,NC 27695,USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Stern
authors.affiliation: 1Prestage Department of Poultry Science,North Carolina State University,Raleigh,NC 27695,USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Ashwell
authors.affiliation: 2Department of Pathobiology,Lerner Research Institute,Cleveland Clinic,Cleveland,OH 44195,USA.
authors.forename: S
authors.initials: S
authors.lastname: Dasarathy
authors.affiliation: 1Prestage Department of Poultry Science,North Carolina State University,Raleigh,NC 27695,USA.
authors.forename: P E
authors.initials: PE
authors.lastname: Mozdziak
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D005786:Gene Expression Regulation; D022124:Hyperammonemia / Q000235:genetics / Q000378:metabolism / Q000662:veterinary*; D024510:Muscle Development / Q000235:genetics; D018006:Myogenic Regulatory Factors / Q000235:genetics* / Q000378:metabolism; D018008:Myogenin / Q000235:genetics* / Q000378:metabolism; D010369:Pectoralis Muscles / Q000378:metabolism; D011201:Poultry Diseases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D018006:Myogenic Regulatory Factors; D018008:Myogenin; D012333:RNA, Messenger
keywords: broiler; hyperammonemia; myogenesis; myogenic regulatory factor; myostatin