Phenotypic Correlations among Growth Performance Traits and Responses to Feed Restriction in Blood Traits of Two Broiler Strains of Chicken Under Heat Stress

This experiment was conducted to evaluate the early effects of feed restriction and breeds on growth performance and body conformation traits of broiler chicken exposed to heat stress conditions. Ninety-six (96) broiler chicken comprising of two strains were used for this experiment. The two broiler strains were both exposed to either feed restriction at early stage of life or ad libitum (control) under heat stress condition. Data on body weight, body conformation traits and blood traits were obtained and analysed. No significant (P > 0.05) effect of breed was observed on body weight and body conformation traits. Body weight and body girth were significantly (P < 0.05) higher in the control chickens than in the feed restricted. Significant (P < 0.05) interaction effect of feeding and breed was observed on body weight but not on body conformation traits. Positively high and significant correlation ranging from r = 0.550, P < 0.01 to r = 0.893, P < 0.001 were recorded between the body weight and body conformation traits from both Arbor Acre and Cobb broiler strains. No significant (P < 0.05) effect of breed, feeding and interaction were observed on the blood haematological and biochemical traits. However, alkaline phosphatase was significantly (P < 0.05) affected by feeding. It is therefore concluded that, both strains could favourably adapt to heat stress irrespective of feeding regimen. The correlations results revealed strong genetic linkage and association between body weight conformation traits and they could be used as markers for selecting one another.