Revista Brasileira de Ciência Avícola
On-line version ISSN 1806-9061
ROSA, PS et al. Performance and carcass characteristics of broiler chickens with different growth potential and submitted to heat stress. Rev. Bras. Cienc. Avic. [online]. 2007, vol.9, n.3, pp. 181-186. ISSN 1806-9061. http://dx.doi.org/10.1590/S1516-635X2007000300007.
In order to evaluate the effects of broiler genotype and of heat exposure on performance, carcass characteristics, and protein and fat accretion, six hundred one-day-old male broilers were randomly assigned in a 2 x 3 factorial arrangement, according to the following factors: genetic group (selected and non-selected broilers) and pair-feeding scheme (Ad32 - reared under heat stress and fed ad libitum; Ad23 - reared at thermoneutrality and fed ad libitum; Pf23 - reared at thermoneutrality and pair fed with Ad32), with a total of six treatments with four replicates of 25 birds each. Independent of pair-feeding scheme, selected broilers showed better feed conversion, higher carcass yield, and lower abdominal fat deposition rate. However, as compared to non-selected broilers, they reduced more intensively feed intake when heat exposed, which promoted significant breast-yield decrease, and more pronounced changes on carcass chemical composition. These findings allows concluding that, in both genetic groups, both environmental temperature and feed-intake restriction influence abdominal fat deposition rate and other carcass characteristics; however, the impact of heat exposure on broiler performance is more noticeable on the selected line.
Keywords : Allometric coefficient; carcass yield; genetic improvement; heat stress.