مقايسه اثر جيره هاي مختلف غذايي بر عملكرد جوجه هاي گوشتي تحت تنش حاد گرمايي

Comparison of the effect of different diets on broiler performance subjected to acute heat stress

The effects of 9 diets in 3 replications were compared on performance of 540 Arian male broilers maintained in an ambient temperature of 30-38°C, at 21-56 days of age, The diets were I control diet cotaining 2900 Kcal/Kg ME which its nutrients adjusted as NRC,1994; and 8 propused diets for reducing heat stress in broilers including:diets containaing 6% fat,7% increasing concentration of all nutrients,7% increasing concentration of all nutrients other than ME 7% increasing ME, and addition of vitamin C, NH4Cl, KCl and aspirin in diet in quantities to 200 ppm , 1% . 0.7% and 0.30%, respectively.In this experiment, diet containing fat and KC1 numerically caused the highest body weight gain and 8 week body weight . Feed conversion ratio of control group was significantly (p<0.05) better than the aspirin guoup . The cloaca temperature of KCl ,NH4CI , and aspirin guoups were significantly (p<0.05) lower than the control group . Liver % in control group was significantly (p0<.01) higher than others. Aspirin significantly (P<0.01) reduced abdominal fat, but other diests did not have asignificant effect. High fat contained died significantly (p<0.05) reduced dietary cost so production, whereas asprin significantly (p<0.01) increased the cost. The results of the experiment showed that the edicts containing high fat may have benefits in reducing the efects of heat stress on broilers.