Meat quality in white striped and wooden breasts of broiler chickens of different genotypes and sex and submitted to different feeding regimes

The present study aimed at evaluating how the presence of white striping (WS) and wooden breast (WB) could affect meat quality in broiler chickens differing for genotype (standard vs. high breast yield), sex, and feeding regime (ad libitum vs. restricted rate, 80% from 13 to 21 d of age). To this aim, 768 day-old chicks were housed in 32 pens and slaughtered at 46 d of age. At the gross examination, genotype and sex did not affect WS rate (74.5% on average), whereas restricted birds tended to have a higher proportion of WS breasts compared to birds fed ad libitum (79.5 vs. 69.5%; P<0.10). Indeed, at the histomorphometric examination, 3.13% of sampled P. major were normal; 26.56% showed mild degeneration; 45.31% exhibited a moderate degeneration; and 25.00% a severe degeneration. The WS score at the gross examination and the score at the histomorphometric examination were moderately correlated (r=0.30; P=0.02). The WS fillets had higher pHu (5.83 vs. 5.87; P<0.05), and lower a* (0.59 vs. 0.81; P<0.05) and b* colour indexes (14.5 vs. 13.7; P<0.05). The overall WB occurrence was of 12.2% and it was significantly lower in females than males (8.0 vs. 16.3%; P<0.05); besides, WB was associated with higher slaughter weights (P=0.06), carcass weights (P<0.02), and dressing out percentage (P<0.01). Cooking losses (22.1 vs. 25.6%; P<0.001) and shear force (2.84 vs. 4.23 kg/g; P<0.001) were higher in breasts with WB than in those without the myopathy.