Effect of Dietary Protein Level and Strain on Growth Performance of Heat Stressed Broiler Chicks

Abstract

An experiment was carried out to study the effect of heat stress on growth performance of three broiler strains fed two different level of dietary protein. Three hundred and sixty, one day old unsexed broiler chicks (120 for each strain, Ross, Cobb and Hubbard strain), were randomly assigned in factoria l arrangement. The total number of chicks for each strain was divided into two groups (A and B), with six replicates (10 chicks per each). Group (A) for each strain was fed on diet contained (23%) Crude Protein (CP) as starter diet for the first four weeks of age and then replaced by a diet contained (21%) CP as finisher diet. Group (B) for each strain was fed a diet contained (21%) CP as starter diet for the first four weeks and then shifted to a diet contained (19%) CP as finisher diet. The minimum and maximum range of ambien t temperature during the experimental period was 34-93°C. Feed intake, body weight gain and feed conversion ratio were recorded on weekly basis throughout the entire duration of experiment, however feed intake per bird for Ross, Cobb and Hubbard strains were 3127.54, 3074.69 and 2850.17g respectively. The results revealed that birds in group (A) for each strain were significantly higher (p<0.05) in live body weight and growth performance than those in group (B) moreover Ross strain got the highest significant (p<0.05) live body weight gain in comparison with Cobb and Hubbard strains. The interaction between strain and diet was significantly (p<0.05) increased for live body weight.