【正文】 and all are easily affected by stress applied to the animals. ?The main task for a muscle is to maintain the level of ATP, and the muscle performs this task even after slaughter. ?Energy metabolism in the meat after slaughter ?Initially the ATP is produced from the conversion of CP and ADP. When the level of CP is reduced to approx. 25% of the resting value, a decrease in glycogen and a conitant increase in lactate formation, decrease in pH and in ATP. ?Consequently a reduction in CP levels will imply a shorter ‘delay phase’ and a lower pH at 45 minutes。 a measure often used to indicate ‘rate’ of pH decrease. The amount of glycogen will determine the extent of the pH decrease, but only if the glycogen concentration has reached the critical value of 53 mmol/kg wet weight. If this is not the case, pH24 will probably not be affected. ?So far a critical value of glycogen has only been calculated for pigs, but reports other animals indicate the existence of a similar value as well. ?In summary, reduction in glycogen levels may result in enhanced ultimate pH, and reduced CP levels will imply a ‘faster rate’ of pH decrease。 both with well recognised and described implications for meat quality. ? The stunning method is of importance ?By CO2stunning the animals pass a phase of excitation during which involuntary contraction of muscles is observed. The energy for these contractions is provided by degradation of both CP and glycogen. The excitation phase is followed by a calm period during which the animals may restore CP values to resting levels, whereas the amount of glycogen is not restored. ?The situation for electrical stunning is somewhat different. Application of the electrodes immediately implies a contraction of all muscles in the animal, and the energy for this type of contraction is mainly derived from CP degradation. As a tetanic contraction of a muscle is elicited at a specified level of voltage, it is the duration of the stunning procedure, and the time from stunning to sticking, which will determine the amount of CP being degraded and thereby its influence on meat quality. Selection on the technological quality of the meat in poultry (E. Le BihanDuval et al, 2021, 7th WCGALP,1114) ?The marketing of poultry has been greatly diversified with a significant increase in joints and processed products. The success of poultry production has been strongly related to improvements in growth and carcass yield, mainly through the increase in breast proportion and reduction in abdominal fatness. ?Recently, researches have been intensified in order to precise the effect of this selection on the processing quality of meat and the possibilities of including meat quality as a criteria of selection in poultry breeding schemes. ?As the proportion of processed products is growing, meat quality will have a major impact on the development of poultry production, especially for highquality products in which supply of food additives is limited. ?As in pork, pH variations significantly affect the storage and the processing qualities of poultry meat, by modifying its waterholding capacity and rheological properties. ? Low pH in the early stage of rigor onset decreases waterholding capacity and the technological quality of meat. These quality defects are usually referred to as pale, soft and exudative (PSE) meat. ?High pH meat known as dry, firm and dark (DFD) presents a poor storage quality. ?In contrast to pork, until recently, very little was known in poultry on the impact of geics on the postmortem pH fall and its geic relationship with meat quality. ? A geic study on several quality indicators measured on breast muscle was conducted in an experimental broiler line with a total of 1076 birds. ? Ultimate pH and trichromatic coordinates (L*: lightness。 a*:redness。 b*:yellowness) were measured. Part of the animals (about 600) were also recorded for the rate of pH fall (pH at 15 min postmortem) and the drip loss of meat. ? REML estimates indicated that meat traits had very significant levels of heritabilities, with the highest values obtained for the color parameters. ? Results: ?Ultimate pH appeared as a determining factor of meat quality, as significant correlations were found between this trait and the lightness and drip loss of meat. ?By contrast, pH at 15 min postmortem was not geically correlated with the other quality indicators. The estimated geic correlation between pH at 15 min postmortem and ultimate pH was found to be equal to zero, showing that the rate and the extent of the postmortem pH fall were governed by different genes. This result agreed with the fact that the ultimate pH of the is supposed to be mostly dependent on the initial glycogen reserves of muscle at the time of slaughter, whereas the rate of pH fall is related to the rate of ATP hydrolysis just after death ?Body weight and breast yield appeared poorly geically related with the measures of pH fall, while moderate negative geic correlations were observed with the redness and yellowness of the meat. This suggested that selection for growth and muscle development would not alter the pH of meat but could slowly modify its color by decreasing the redness and yellowness indicators