Effects Of Feed Restriction On Performance, Nutrient Utilization, Plasma MDA Concentration And SOD Activity In Broilers

Effects of Feed Restriction on Performance and Apparent Nutrient Availability of Avian Broilers1008 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. 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(P>0.05).Carcass expressed as a percentage of BW,and abdominal fat expressed as a percentage of carcass were unaffected by treatment(P>0.05).The mortality was not different(P>0.05)at 42 d across treatments.The apparent energy,crude protein,calcium and phosphorus availability were unaffected by treatment during the period of restriction.It appeared that the severity of our experiments allowed Avian broiler to adapt to feed restriction when ambient temperature was maintained at high level.Effects of Feed Restriction on Performance,Gastrointestinal Development ,Tibia Quality,Lipid Peroxidation and Enzymatic Antioxidant Activity of Broilers440 one-day-old Arbor Acre broilers were distributed into 4 treatment groups with 5 pens of 22 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. Feed-restricted broilers failed to catch up the control birds in BW at 42 d of age(P<0.05), and the FGR was higher in 100% ad libitum group(P<0.05).No treatment effects were observed on carcass yields or abdominal fat(P>0.05).The mortality was not different(P>0.05)at 42 d across treatments.Relative weight of small intestine was not affected by restricted feeding at 22 d of age(P>0.05).The relative weight of Proventriculus plus gizzard and relative length of small intestine of 90% ad libitum group were greater than the control group(P<0.05).Tibia ash was increased by feed restriction at 22 d of age(P>0.05),tibia phosphorus of 90% ad libitum group were higher than the control group(P<0.05).Feed restriction had no effect on the relative weight of digestive organs and,the relative length of small intestine and tibia quality in 43-d old chickens(P>0.05).The plasma MDA concentration of 80% ad libitum group was markedly higher than thre control group,plasma SOD activity was not affected by feed restriction.Arbor Acre broilers should not be restricted ,at least in our experiment.