ABSTRACT. Wooden breast myopathy (WB) strongly affects the poultry industry mainly in terms of consumers rejection and economical loses, due to morphological changes in broiler muscle tissue and consequently low meat quality. The aim of this study is to evaluate the histomorphometry of muscle fibers of breast fillets of broilers with severity levels of WB myopathy. The histological evaluation considered 30 samples of the pectoralis major muscle and the level of WB myopathy (ten normal fillets, ten moderate fillets, and ten severe fillets). Fillets with a severe level of WB present low average fiber number, high average fiber diameter, low percentage of fibers with diameter of less than 20 µm, low percentage of fibers with diameter between 20 and 40 µm, and high percentage of fibers with diameter between 40 and 70 µm. Fiber cross-sectional area is greater in fillets affected by moderate and severe WB. Thus, fillets with a severe level of WB damage the muscle fiber structure and contribute more severely to the degenerative processes of breast meat.

ABSTRACT The objective of the present research was to study the incidence of broiler carcass condemnations over eleven years and identify the productive phase that causes greater loss in slaughter process. The origin of these condemnations was determined before and after fasting. Evaluated broilers were reared in positive pressure warehouses and slaughtered between 28 and 34 days old with carcass weight ranging from 0.7 to 1.4 kg. Fasting occurred, on average, 9 h before the slaughter. Condemnation and slaughter data were collected from 2004 to 2014 in a slaughterhouse with slaughter capacity of 120,000 broilers/day. The causes of rearing condemnations were airsaccullitis, arthritis, abscess, ascites, cachexia, cellulitis, colibacillosis, dermatosis, salpingitis, hemorrhagic syndrome, and neoplasia; and the causes of pre-slaughter and slaughter condemnations were bruising, fracture, inadequate bleeding, excessive scaling, contamination, dehydration, death at the platform, disgusting appearance, and delayed evisceration. The mean values of total and partial condemnations per year, occurrence and proportion of condemnations index (OCI) for every thousand broilers slaughtered, and rates of pre and post-fasting condemnations were calculated. Condemnations rates (%) and OCI were higher after fasting; partial and total contamination stood out, with a frequency of 77% and 30%, respectively, after fasting. Long fasting, uneven lots or unbalanced equipment may cause extravasation of the gastrointestinal contents and contaminate broiler carcasses. Practices such as monitoring fasting and equipment adjustment to broiler carcass size may reduce carcass condemnation incidence.