Effect of selection for or against abdominal fatness on muscle and meat characteristics of broilers

Meat quality (pH, colour, drip and cooking loss, Warner-Bratzler shear force) and muscle characteristics (lipid and glycogen contents) were compared among two experimental divergent lines of broilers, selected for high abdominal fatness (HF) or low abdominal fatness (LF). By comparison to the LF line, the HF line exhibited a 2.8 fold higher abdominal fat percentage. It also exhibited a slightly higher body weight (+5%) and a 10% lower breast yield. The fat content of the breast Pectoralis major (P. major) muscle was low and similar in the two lines (around 0.9%). By contrast, the P. major muscle glycogen level at death was higher in the HF than in the LF line (111.6 vs 93.6 μM). There was no difference between the two lines regarding the rate of early post-mortem pH drop in breast muscle. However, in accordance with its higher muscle glycogen level at death, the HF line exhibited a lower ultimate pH than the LF line (5.66 vs 5.79). Moreover, there was a negative correlation between ultimate pH and abdominal fat yield (-0.52). The consequence for the HF line was a breast meat with a higher drip loss during storage and a lighter (higher L*) and less coloured (lower a* and b*) aspect. However, the cooking loss and the Warner-Bratzler shear force of the cooked meat were similar in the two lines. This study suggested that selection against abdominal fatness modify breast muscle metabolism by decreasing glycogen reserve, and therefore is likely to improve processing ability of breast meat by increasing ultimate pH.