Performance and physiological response of heat stressed growing pullets fed diets supplemented with ascorbic acid

Résumé

Effects of dietary supplementation of Ascorbic Acid (AA) on performance and physiological response of growing pullets were investigated in a 7-week trial. In a completely randomized design, Bovan Brown pullets (n=96) aged 12 weeks weighing 0.81±0.04 kg were randomly allotted to three treatments of four replicate and each replicate comprised eight birds. The pullets were initially fed basal diet for three weeks followed by dietary supplementation with AA at 0 (T1), 300 (T2) and 600 mg/kg (T3). Feed and water were provided to the pullets ad libitum. Performance and physiological parametersweremonitored.Data were subjected to ANOVA and polynomial regression and means separated at α0.05. Ambient temperature, relative humidity and temperature humidity index were 29.0±1.5 °C, 71.9±0.3 % and 26.9±1.3, respectively. Feed intake (kg) (0.89, 0.87, 0.88) and livability (93.8, 96.9, 96.9%) of pullets on T1, T2 and T3, respectively were not significantly affected (P>0.05) by supplemental AA. Weight gain (kg) of pullets on T1 (0.36) and T3 (0.42) were similar (P>0.05) but were significantly lower (P<0.05) than T2 (0.47). Feed conversion ratio of pullets on T2 (1.89) and T3 (2.09) were significantly lower (P<0.05) than T1 (2.48). Panting rate (Breath/min) of pullets on T1 (231.8) and T2 (225.0) were similar (P>0.05) but significantly higher (P<0.05) than in T3 (207.8). Rectal temperature of pullets on T3 (41.9) was lower than T1 (41.5). In conclusion, dietary supplementation of AA improved performance and physiological response of growing pullets in this study.