Performance and carcass traits of three commercial broilers genotypes fed with different diets

Objetivou-se, com esse trabalho, avaliar caracter?sticas de desempenho e de carca?a de tr?s gen?tipos comerciais de frangos de corte, nos per?odos de 1 a 35, 1 a 42 e 1 a 49 dias de idade. Foram utilizados 2.970 pintos de um dia, machos e f?meas, sexados, de tr?s gen?tipos comerciais de frangos de corte (Cobb 500, Hubbard Flex e Ross 308). Foram utilizados tr?s programas nutricionais, com diferentes n?veis de amino?cidos. As aves foram distribu?das em delineamento inteiramente casualizado, em ensaio fatorial 3x3x2 (gen?tipo x ra??o x sexo), com cinco repeti??es e 33 aves/parcela. As caracter?sticas convers?o alimentar (CA), ganho em peso m?dio di?rio (GPMD) e consumo de ra??o m?dio individual (CR) peso corporal aos 35 (PC35), 42 (PC42) e 49 (PC49) dias de idade. Duas aves de cada repeti??o foram abatidas aos 35, 42 e 49 dias de idade para se avaliarem as caracter?sticas de carca?a: peso corporal ao abate, peso e rendimento da carca?a, peso e rendimento dos cortes (peito, pernas e asas). Verificou-se, no per?odo de 1 a 35 dias, intera??o entre gen?tipo x sexo para GPMD e PC35. No per?odo de 1 a 42 dias de idade, n?o houve diferen?as entre os gen?tipos para PC42, CR, GPMD ou CA. Verificou-se intera??o significativa sexo x gen?tipo para peso do peito, sendo que, entre os frangos de corte machos, as aves Cobb 500 apresentaram maior peso do peito, n?o diferindo dos machos Ross, que por sua vez n?o diferiram dos machos Hubbard. Por fim, no per?odo de 1 a 49 dias de idade, n?o houve diferen?a entre os gen?tipos para CR, GPMD ou PC49. De maneira geral, os desempenhos das aves Cobb 500, Hubbard Flex e Ross 308 n?o foram muito diferentes, sendo essas diferen?as mais presentes nas caracter?sticas de carca?a. A ra??o basal apresentou, de forma geral, melhores resultados que as ra??es com mais ou menos 10% de amino?cidos, evidenciando a boa adequa??o dos n?veis nutricionais da mesma. Os machos apresentaram-se superiores, de forma geral, para as caracter?sticas de desempenho e de carca?a, em rela??o ?s f?meas.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013.ABSTRACT The objective of this study was to evaluate performance characteristics and carcass traits of three genotypes of commercial broilers in the periods 1-35, 1-42 and 1-49 days of age. We used 2,970 day-old chicks, male and female, sexed, three cultivars of commercial broilers (Cobb 500, Hubbard Flex and Ross 308). We used three nutritional programs with different levels of amino acids. The broilers were distributed in a completely randomized design in factorial design 3x3x2 (genotype x diet x sex) with five replications and 33 birds / plot. The characteristics of feed conversion (FC) , average daily weight gain (ADG) and feed intake average individual (CR) body weight at 35 (PC35) , 42 (PC42) and 49 (PC49) days of age . Two birds per replicate were slaughtered at 35, 42 and 49 days of age to evaluate carcass traits: body weight at slaughter weight and carcass yield, weight and yield of cuts (breast, legs and wings). It was found in the period 1-35 days genotype x sex interaction for ADG and PC35. In the period 1-42 days of age, there were no differences among genotypes for PC42, CR, DWG or CA. There was significant interaction sex x genotype for breast weight, and between broilers, Cobb 500 had higher breast weight, did not differ from Ross 308 males, who in turn did not differ from males Hubbard. Finally, in the period 1-49 days of age, there was no difference between genotypes CR, DWG or PC49. In general, the performance of broilers Cobb 500, Hubbard Flex and Ross 308 were not very different, and these differences were more present in carcass characteristics. The basal diet showed, in general, better results than diets with more or less 10 % of amino acids, which shows the good nutritional adequacy of the same. The males showed themselves superior, overall, to the performance characteristics and carcass, compared to females