Comparative efficacy of different supplements used to reduce heat stress in broilers

A study was conducted to compare the effects of supplemental betaine (1200 mg/kg),vitamin c (vc,200 mg/kg),vitamin e (ve,300 mg/kg) and sodium bicarbonate (nahco 3,2 g/kg) on the performance of 250 broilers during hot (38-40°c) and humid (40-93%) environmental conditions. body weight and feed intake was recorded weekly. on day 35 ph,anti nd virus titre (ha,hi),na,k and cl concentrations and total leukocytic counts (tlc) were determined blood samples. all diets containing feed supplements gave better (p<0.05) weight gain and fcr than control. lowest blood ph (p<0.05) was observed in birds fed supplemental nahco 3 compared to all other treatment groups. serum na and k levels were higher (p<0.05) in control group than all other supplemental groups. maximum tlc (p<0.05) were observed in birds fed control diet compared to lower levels in birds fed diets containing nahco 3. a lowest (p<0.05) mortality was observed with betaine (3.3%),whereas,highest mortality (33%) was in control group. this study showed that appropriate feed supplements attenuate the decline in performance caused by heat stress. among different diet supplements,betaine and nahco 3 offered better protection against heat-stressrelated depression in performance of broilers. © 2012 zoological society of pakistan.