Effect of different levels of feed restriction on performance and body temperature of broiler chickens under heat stress conditions

An experiment was conducted to investigate the effects of different levels of feed restriction on performance and body temperature of broiler chickens under heat stress condition. A total number of 240 cockerels from Ross 308 commercial strain were used as a completely randomized design. Chickens were kept under heat stress condition (35±2 °C) for 4 hours a day from 7 to 21 days of age. Treatments were different levels of feed restriction (70, 80 and 90 percent of control bird) from 7 to 14 days of age and (80 and 90 percent of control bird) from 7 to 21 days of age. At 42 days of age no differences were found between treatments for feed intake, body weight gain and feed conversion rate but for 7 to 21 days of age feed intake and body weight gain were significantly lower in feed restricted birds, also in feed restricted birds till 21 days of age feed conversion was lower than control birds. Duodenum weight in birds under 80 percent feed restriction till 21 days of age was the lowest. Different levels of feed restriction under heat stress condition didn’t have any effect on length and ash percent of tibia. In comparison before and during heat stress uric acid and glucose levels were lower after heatstress. Whereas triglyceride and HDL were increased during heat stress. At 14 days of age, control group was shown the highest rectal temperature after exposure to heat stress. But during heat stress at 21 days of age the highestrectal temperature was observed in feed restriction birds till 14 days of age. Finally we concluded that feed restriction under heat stress conditions moreover its useful effects due to chicken’s compensatory growth, also causes a decrease in feed cost and almost adjustment of harmful impacts of heat stress.