Broiler meat quality: effect of selection for increased carcass quality and estimates of genetic parameters

Ultimate pH (pHu), color measurements, and water holding capacity of the chicken Pectoralis major muscle were compared between birds of an experimental line selected for 13 generations for increased BW and breast meat yield and reduced abdominal fat percentage and its control line. Ultimate pH differed slightly between lines after selection, with values of 5.78 +/- 0.10 and 5.68 +/- 0.12 in the selected and control birds, respectively. Drip loss was significantly lower in the selected birds. Although selection did not modify lightness L*, it led to paler meat, as redness a* and yellowness b* were significantly lower in the selected line than in the control line. Ultimate pH of the meat was related to lightness and drip loss (with mean correlations over both lines of -0.59 and -0.40, respectively). Storage of the meat resulted in similar color variation in both lines, with a significant increase in a* and b* until 3 d postslaughter and in L* after 6 d postslaughter. Estimates of the genetic parameters of the criteria of meat quality were calculated in the selected line. The estimates suggested that there is a predominant role of genetics in the control of these traits, with heritability estimates of 0.49 +/- 0.11 for pHu, 0.75 +/- 0.08 for L*, 0.81 +/- 0.04 for a*, and 0.64 +/- 0.06 for b*. A significant negative genetic correlation (-0.65) was found between pHu and L*. The genetic correlation between a* and b* measurements was estimated at 0.72.