SERUM CORTICOSTERONE, PERFORMANCE AND SLAUGHTER TRAITS OF COBB500 BROILER CHICKENS FED LYCOPENE-SUPPLEMENTED DIETS DURING HEAT PERIOD

Résumé

Poultry farmers in the tropics suffer great loss in broiler production to extreme environmental heat, especially at post brooding stage when broilers would have grown more feathers and their metabolic heat generation rate is high. This study therefore investigated ameliorative effects of lycopene supplement on growth performance, slaughter traits and serum corticosterone level of COBB500 broiler chickens managed during heat period. A total of 120 birds were selected at 4th week of rearing and allotted into a control and three experimental groups designated as T1, T2 and T3 (treatments 1, 2, and 3), each in 3 replicates. The four groups were fed the same starter diet for 4 weeks and then differently on finisher diets supplemented with lycopene at 0mg/kg feed (control), 5mg/kg (T1), 10mg/kg (T2), 15mg/kg (T3) for 3 weeks. Data obtained were analysed using ANOVA. Results showed that at 5mg/kg supplementation level, lycopene significantly (p<0.05) decreased serum concentration of corticosterone and thigh muscle weight. Although, most performance indices were not statistically different except feed intake, the best feed conversion ratio was obtained at T3 (15mg/kg) lycopene supplementation. Therefore, at 5mg/kg feed, lycopene can be supplemented in diets to reduce the serum corticosterone level in COBB500 broiler chickens managed under hot climate.