Desempenho e características de carcaça de duas linhagens de frangos de corte criados sob duas densidades de alojamento

Abstract

The objective of this study was to evaluate the performance and carcass characteristics of broiler chickens of two strains raised under two housing densities. A total of 720 one-day-old male and female chicks were used, of which half of each strain was distributed in a completely randomized experimental design in a 2x2 factorial scheme, with two strains (Ross 308 AP and Ross PP) and two rearing densities (11 and 13 birds/m²), totaling four treatments and 12 replicates. The performance of the birds was evaluated in the period from 1 to 42 days of age. To evaluate the carcass characteristics, two birds from each portion, one male and one female, were slaughtered at 42 days of age. According to the results of performance and carcass characteristics, there was no significant interaction between the factors strain and rearing density. However, it was observed that feed intake, weight gain, final weight at 42 days of age and amount of kg of live weight produced per square meter were higher for birds of the PP strain, with no significant difference between the strainsfor feed conversion. In turn, the density of 13 birds/m² resulted in significantly lower feed intake, weight gain, final weight at 42 days and amount of kg of live weight produced per square meter in relation to the density of 11 birds/m², with no significant difference for feed conversion. In the evaluation of carcass characteristics, a significant interaction was detected between the factors strain and sex for abdominal fat proportion, where females of the PP strain showed greater fat deposition in relation to birds of the AP strain. There was no effect of rearing density for any of the carcass parameters. However, the comparison between the strains showed that birds of the PP strain had lower breast and wing yield, in addition to higher back yield. It is concluded that, regardless of the stocking density, the PP strain birds had a greater potential for weight gain and, consequently, a higher body weight at 42 days of age, resulting in 1.23 kg of BW/m² of shed more than the AP strain birds. However, the PP strain birds have a lower breast and wing yield, in addition to a higher proportion of back. The PP strain females have a greater potential for abdominal fat deposition compared to the males of the same strain and compared to the AP strain females. On the other hand, the increase in the stocking density from 11 to 13 birds/m² of shed reduces the consumption and weight gain of both strains, without compromising feed conversion and carcass characteristics, but this practice increases the production of kg of BW per m² of shed by 8.5%.