title: Breed differences in the biochemical determinism of ultimate pH in breast muscles of broiler chickens--a key role of AMP deaminase?
abstract: The biochemical determinism of ultimate pH (pHu) was studied in the pectoralis muscle of broiler chickens. Thirty birds of 3 genetic types (a fast-growing standard (FG), a slow-growing French "Label Rouge" (SG), and a heavy line type (HL)) were kept under conventional breeding methods until the usual marketing age (6, 12, and 6 wk for FG, SG, and HL birds, respectively). The birds were divided into 3 different antemortem treatment groups: minimum stress, shackling for a longer time (2 min), and heat stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning). The birds were slaughtered on the same day. The pHu differed (P < 0.001) among the 3 genetic types, ranking as follows: FG (5.95+/-0.01) > HL (5.85+/-0.02) > SG (5.73+/-0.02). In SG and HL birds, pHu was strongly correlated with muscle glycogen content at slaughter (r = -0.74 and -0.82; P < 0.01 respectively), whereas this correlation was weak in FG birds. Regardless of genetic type, neither buffering capacity nor lactate accumulation significantly contributed to pHu variations (P > 0.05). The activity of adenosine monophosphate deaminase (AMPd) was significantly higher in FG chickens (0.98+/-0.31; P < 0.05) than in HL and SG birds (0.46+/-0.24 and 0.34+/-0.18, respectively). Significant correlations were found between AMPd activity, pHu, and glycolytic potential (GP) at slaughter (r = 0.34 and -.29; P < 0.01, respectively). Further research is needed to study in more detail the role of AMPd in the determinism of pHu, particularly in fast-growing broilers.
authors.affiliation: Laboratoire de Zootechnie et Qualités des Produits Animaux (Unité soutenue par l'INRA), ENSAT, Avenue de l'Agrobiopole, BP 107, 31326 Auzeville Tolosane, France. rammouz@ensat.fr
authors.forename: R
authors.initials: R
authors.lastname: El Rammouz
authors.forename: C
authors.initials: C
authors.lastname: Berri
authors.forename: E
authors.initials: E
authors.lastname: Le Bihan-Duval
authors.forename: R
authors.initials: R
authors.lastname: Babilé
authors.forename: X
authors.initials: X
authors.lastname: Fernandez
mesh_terms: D000659:AMP Deaminase / Q000502:physiology*; D000249:Adenosine Monophosphate / Q000032:analysis; D000818:Animals; D001947:Breeding; D002645:Chickens / Q000235:genetics* / Q000254:growth & development; D003401:Creatine / Q000032:analysis; D005838:Genotype; D018882:Heat Stress Disorders; D006863:Hydrogen-Ion Concentration; D007291:Inosine Monophosphate / Q000032:analysis; D008460:Meat / Q000032:analysis; D010369:Pectoralis Muscles / Q000737:chemistry*; D013045:Species Specificity; D013312:Stress, Physiological
chemical_list: D007291:Inosine Monophosphate; D000249:Adenosine Monophosphate; D000659:AMP Deaminase; D003401:Creatine