Effects of Seasonal Change in the Thermal Environment on Physiological Responses of Unsexed Broilers to Dietary Supplementation of Antithyroid Drug Carbimazole

Abstract

The objective of this study was to evaluate the physiological responses of the unsexed broilers to dietary supplementation of carbimazole (0.1 g/bid/day) during tropical summer and winter conditions. There were marked changes in. most of the parameters investigated. The rectal temperature (Tr) was higher (P<0.05) in summer compared to the winter values in both groups, supplementation of carbimazole caused a decrease (P<0.01) in (Tr). The mean values of food intake and body weight (BW) were lower (P<0.05) in summer in both groups. Supplementation of carbimazole caused decreases in the mean food intake in both seasons (P<0.05) and a decrease in. the mean B.W. only in. winter ter (P<0.05). The plasma glucose concentration was lower (P<0.05) in summer and supplementation of carbimazole caused a decrease (P<0.05) in. the plasma glucose level only in win. ter. The serum cholesterol concentration was lower (P<0.05) in. summer and in. both seasons supplementation of carbimazole caused an increase (P<0.05) in serum cholesterol concentration.