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This Article Full Text (PDF) All Versions of this Article: jas.2008-1062v1 86/11/2888    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sibut, V. Articles by Berri, C. Search for Related Content PubMed PubMed Citation Articles by Sibut, V. Articles by Berri, C.

AMP-activated protein kinase involved in the variations of muscle glycogen and breast meat quality between lean and fat chickens

V. Sibut^,*, E. Le Bihan-Duval, S. Tesseraud, E. Godet, T. Bordeau, E. Cailleau-Audouin, P. Chartrin, M. J. Duclos and C. Berri

INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France ^* Institut Technique Avicole, F-37380 Nouzilly, France.

berri{at}tours.inra.fr

Abstract

The present study was aimed at evaluating the molecular mechanisms associated with the differences in muscle glycogen content and breast meat quality between 2 experimental lines of chicken divergently selected on abdominal fatness. The glycogen at death (estimated through the glycolytic potential) of the Pectoralis major muscle and the quality of the resulting meat were estimated in the 2 lines. The fat chickens exhibited greater glycolytic potential, and in turn lower ultimate pH than the lean chickens. Consequently, the breast meat of fat birds was paler and less colored, and exhibited greater drip loss compared with that of lean birds. In relation with these variations, the AMP-activated protein kinase (AMPK) transcription and activation levels were investigated. The main difference observed between lines was a 3-fold greater level of AMPK activation, evaluated through phosphorylation of AMPK-(Thr¹⁷²), in the muscle of lean birds. At the transcriptional level, data indicated a concomitant down- and up-regulation for the 1 and 2 AMPK subunit isoforms, respectively, in the muscle of lean chickens. Transcriptional levels of enzymes directly involved in glycogen turn over were also investigated. Data showed greater gene expression for the glycogen synthase, glycogen phosphorylase, and the subunit of phosphorylase kinase in lean birds. All together, these data indicated that selection on body fatness in chicken alters the muscle glycogen turn over and content and as a consequence the quality traits of the resulting meat. Alterations of AMPK activity could play a key role in these changes.

Key Words: AMP-activated protein kinase • chicken • fatness • glycogen • meat quality • pH