Exigências de energia e composição da carcaça de galos reprodutores pesados em função do consumo energético na fase de reprodução

Abstract

RESUMO -Dois experimentos foram realizados para estimativa da exigência e da composição de carcaça de machos reprodutores de corte em resposta a cinco níveis de ingestão de energia metabolizável (EM). Para avaliar o peso corporal, o volume de sêmen, a concentração espermática, a motilidade, o vigor e a fertilidade dos espermatozóides, foram selecionadas 450 fêmeas e 75 machos da linhagem Cobb-500 e, para avaliar a composição química da carcaça em MS, PB e gordura em função do consumo de energia, foram utilizados 30 machos. O delineamento experimental foi o inteiramente casualizado com cinco tratamentos (290, 310, 330, 350 e 370 kcal de EM/ave/dia). No ensaio de desempenho reprodutivo, cada tratamento foi composto de 15 repetições de um galo e seis fêmeas e, no ensaio de avaliação da carcaça, cada tratamento continha duas repetições de três galos (três abatidos às 45 e três às 61 semanas de idade). A motilidade, o vigor e a fertilidade dos espermatozóides foram influenciados de forma quadrática pelo nível de ingestão de EM. O peso corporal e os teores de gordura e proteína da carcaça cresceram linearmente com o aumento do consumo de EM. Com base nas estimativas obtidas para motilidade, vigor e fertilidade, recomenda-se nível médio de 347 kcal de EM/galo/dia para atender às necessidades de machos reprodutores de 26 a 61 semanas de idade.Palavras-chave: desempenho reprodutivo, fertilidade, nutrição, sêmen Energy requirements and carcass composition of male broiler breeders as a function of energy intake during the reproduction periodABSTRACT -Two trials were carried out to estimate the nutritional requirement and carcass composition of male broiler breeders according to five levels of metabolizable energy (ME) ingestion. Four hundred and fifty females and 75 males of Cobb-500 strain were selected to evaluate body weight, semen volume, spermatic concentration, motility, vigor and fertility of spermatozoa. Thirty males were used for evaluation of carcass chemical composition (DM, CP and crude fat [CF]) as a function of energy intake. The experiment was analyzed as a completely randomized design with five treatments (290, 310, 330, 350 and 370 kcal of ME/rooster/day). In the first trial (reproductive performance), each treatment was represented by 15 replicates of one rooster and six females. In the second trial (carcass evaluation), each treatment consisted of two replicates of three roosters (three slaughtered at 45 weeks and three at 61 weeks of age). Treatment quadract effect on motility, vigor and the fertility of spermatozoa was observed. Body weight and contents of fat and CP in the carcass increased linearly as ME intake increased. Based on the estimates of mobility, vigor and fertility, the 347 kcal of ME/rooter/day level is recommended to meet the requirements of male broiler breeders from 26 to 61 weeks of age.

Feeding management strategy for male broiler breeders and its effects on body weight, hatchability and fertility

“…Low-density feeds have been frequently used to control broiler breeders' body weight (Leeson & Summers, 2000). In the present study, the dietary energy level of the rooster diet (treatment 2) was the same as that recommended by Rostagno et al (2011); however, Borges et al (2006a) suggested that a lower energy level (2,660 kcal ME/kg) should be applied. The results also show that body weight was directly and positively correlated with energy intake, as previously demonstrated by Sexton et al (1989).…”

“…Excessive energy is mainly stored as body fat, increasing body weight and reducing both hatchability and fertility (Pearson & Herron, 1981;Leeson, 1999 andBorges et al, 2006a). As energy is the most expensive nutrient of feeds (Borges et al, 2006a), a specific male diet, containing energy levels, may reduce feeding costs and significantly improve reproductive efficiency.…”

“…According to Borges et al (2006a), the nutritional management of female broiler breeders has received more attention compared with males. Although males comprise only 10% of a flock, they represent 50% of the genetics of the chicks and are essential for fertility.…”