Effects of Feed Restriction on Growth and Carcass Characteristics of Broiler Chickens

Two experiments were conducted to determine the effects of quantitative feed restriction on performance and carcass characteristics of broiler chickens.In experiment 1,1008 one-day-old Avian broilers were distributed into 4 treatment groups with 7 pens of 36 broilers each group.One group was fed ad libitum as the control group and the others were feed-restricted from 10 to 20 d by giving 100,90,or 80% of the feed consumed ad libitum by control birds the previous day.By 21 d of age all birds fed grower diets ad libitum.Due to high temperature in summer season,average room temperature was 36℃ during realimentation in experiment 1.In experiment 2,440 one-day-old Arbor Acre broilers were distributed into 4 treatment groups with 5 pens of 22 broilers each group.The design and diets were identical with experiment 1.Results from experiment 1 indicated that the BW at 42 d and feed gain ratio(FGR) were not significantly different between unrestricted and restricted broilers(P0.05).Feed-restricted broilers failed to catch up the control birds in BW at 42 d of age(P0.05),and the FGR was higher in 100% ad libitum group in experiment 2(P0.05).Carcass expressed as a percentage of BW,and abdominal fat expressed as a percentage of carcass were unaffected by treatment(P0.05).The mortality was not different(P0.05)at 42 d across treatments.It appeared that the severity of our experiments allowed Avian broiler to adapt to feed restriction as far as temperature is maintained at an accurate level.Arbor Acre broilers should not be restricted,at least in our experiment.