ARE ONE EARLY MUSCLE PH AND TEMPERATURE MEASUREMENTS SUFFICIENT TO DETECT PSE BREAST MEAT IN TURKEYS?

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إنجليزي. Within a large flock of turkey toms (2000 BUT9 conventionally reared and slaughtered), early muscle pH measurements were randomly done to distinguish two groups of birds presenting low (fast glycolyzing, GR) or normal (normal glycolyzing, GN) values. Subsequently, ultimate pH values and meat quality parameters were also recorded. Meat quality parameters from GR or GN samples differ more or less indicating more or less severe PSE conditions. Proteins extracted from the samples at 20 min post mortem were quite similar while they largely differ at 24 h post mortem. Moreover, among the GR birds, a subgroup of animals (called AB) presented SDS-PAGE profiles largely different from other GR or GN birds. All the subsequent analysis developed on meat quality parameters as well as for protein extractabilities also differ between AB and other animals indicating that they must be considered differently in term of PSE syndrome development. Western blots against Myosin Heavy Chain and actin at 24 h post mortem indicate that myofibrillar proteins alterations are different in AB and GR or GN samples. At 20 min post mortem, glycogen content was the lowest in AB samples while the glycolytic potential was similar in all samples at the time of death. Measurements of PFK enzyme specific activity did not indicate a different regulation of post mortem glycolysis in AB samples. Our results suggest that a unique pH measurement at 20 min post is insufficient to detect animals the more prone to develop a severe PSE syndrome in turkeys. In consequence, it is suggested that a more precise evaluation of the kinetic of pH and temperatures fall has to be conducted to better understand the etiology of meat quality parameters alterations in poultry.