Alometria de frangos de corte com diferentes graus das miopatias peitorais wooden breast e white stripping

Abstract

Considering pectoral myopathies has become frequent in the poultry, causing many economic losses, research was carried out on the allometric growth of chicken breast in order to verify the speed of breast growth and if the growth of this muscle is early or late in relation to body growth, whether or not these fillets are affected by pectoral myopathies. Therefore, it was necessary to identify the degrees of myopathy in 35-day-old chickens and associates this changes in muscle breast with the growth rate. A research was carried out where 300 male and female day-old Cobb 500® chicks and slaughtered at 35 days old with live weight ranging from 1,356 kg to 2,956 kg. The carcasses were weighed hot gutted and chilled carcasses free of head and feet. After weighing, commercial cuts were made to weigh the chest, thigh, drumstick, wings, back and feet, then the breasts were evaluated for the presence and severity of myopathies and selection for subsequent allometric analyzes. Chicken with normal breast fillets, showed isogonic growth for thigh and thigh, whereas the feet, chest, wings and back had a heterogeneous growth, feet and chest with fast growing rate and wings and back with slow growing rate. For all degrees of White Striping associated with Wooden Breast, we found heterogeneous growth for all parts, with breast and thigh feet showing positive heterogeneous growth, in contrast, wings, back and thigh showed negative heterogeneous growth. Therefore, breast showed fast growth rate in relation to the body, also, all the degrees of myopathies were showed relation with the accelerated growth of the breast, which indicates that the selection of animals for high performance may indeed to be one of the main causes of the pectoral myopathies.