RESPONSE OF MALE AND FEMALE BROILERS TO DIET PROTEIN

Two experiments were conducted to note the broilers' response to graded levels of dietary protein (CP). Female birds were fed one of six diet series ranging from 22–20–18 to 18–18–16% CP from 0–21 days, 21–35 days and 35–42 days, respectively. Males were fed diet series from 28–24–22 to 20–18–16 over the same time periods (Table 1). Each diet program was tested with four replicate groups of 60 birds. Body weight and feed intake were monitored at time of feed change-over and at termination of experiment. Twenty birds per replicate were used for carcass analyses. Females were heavier when diets of higher protein content were offered (P < 0.05). These birds consumed more feed (P < 0.05) but exhibited feed efficiency that was not different to birds fed diets of lower protein content. Carcass weight and breast meat yield were not influenced by diet, although higher-protein diet series resulted in reduced proportional abdominal fat pad size (P < 0.01). Diet protein had no effect on body weight of male birds at 42 d (P > 0.05). Male birds reared on a program involving die lowest CP levels of 20–18–16 exhibited inferior feed utilization relative to birds from most other treatments (P < 0.05). Programs with low-protein diets for males resulted in reduced carcass weight, reduced breast meat yield and increased abdominal fat deposition (P < 0.05). It is concluded that male birds can be reared on very low protein diets without loss of weight, although carcass quality will be inferior. Female broilers are heavier when diet protein intake is increased through use of diets with higher protein content. Key words: Broiler, diet protein, performance, carcass composition