Genetic evolution of pure paternal and maternal broiler lines

An experiment was carried out to determine the genetic changes in performan ce, carcass composition and measures of bone size and resistancy of paterna l (LL, LLc, ZZ and LC1) and maternal lines (PP, PPc, KK and LC2). The genet ic changes were estimated as deviations between selected and control lines (LL-LLc and PP-PPc). The body weight selection improved feed:gain ratio, bu t did not cause any correlated response in the carcass traits. The genetic changes in the weight gain are not acompanied by correlated changes in the bone resistancy. Diferent selection emphasis in the selection of paternal a nd maternal pure lines is altering the Ca, water and fat content of the car cass.