Abstract
The aim of this study was to investigate the effect of feed withdrawal in reducing the negative effect of heat stress in broilers subjected to cyclic heat stress (25-36-25) 5C on some productive and physiological traits . Thirty six of broiler chicks (Fawbro) raised on standard condition for the first 3weeks. The experimental treatments were started from 22days of age till the age of marketing (56days).On day 22 of ages the chicks were weighted ,numbered and distributed randomly to four treatments (1) the control(ad Libitum) , (2)feed withdrawal for eight hours(1000-1800) , (3)feed withdrawal for nine hours(900-1800) , (4)feed withdrawal for ten hours(800-1800) with 3 replicates for each treatment. Statistical analysis of data showed No significant differences (p≤0.05) as a result of feed withdrawal for live body weight , average weekly weight gain , feed consumption , feed conversion ratio , Dressing percentage , Red blood cells number , hemoglobin concentration , packed cells volume and relative growth rate in seven and eight weeks . Feed withdrawal resulted in significant decrease (P ≤ 0.05) in blood glucose concentration gradually as the feed withdrawal increase , glycogen concentration in liver for feed withdrawal 10 hours treatments , blood pH and body temperature for feed withdrawal treatments at six and eight weeks . and significant increase(P ≤ 0.05) in , glycogen concentration in heart of feed withdrawal 10 hours . Decrease in mortality.
