Influence of Dietary Supplementation with Zinc on Sex Hormones Concentrations of Broiler Breeder Chickens

Abstract

2 Abstract: This study was conducted to determine the effect of supplementing the diet with different levels of zinc (0, 50, 75, 100 mg/kg of diet) on sex hormones concentrations of broiler breeder chickens. A total of 132 (96 females and 36 males) of Cobb 500 broiler breeder chicken, 45 weeks old were used in this study. These birds were randomly distributed equally into four dietary treatments with three replicates each. Each treatment group constituted of 32 females and 12 males. Treatment groups were as following: T1: Birds fed the basal diet without any addition (0 Zn) (control), T2: Birds fed diet supplemented with 50 mg Zn (pure zinc)/kg of diet, T3: Birds fed diet supplemented with 75 mg Zn (pure zinc)/kg of diet and T4: Birds fed diet supplemented with 100 mg Zn (pure zinc)/kg of diet. Concentration of testosterone hormone in bird males was determined at 54, 58 and 66 weeks of age, whereas concentrations of estrogen and progesterone hormones in bird females were determined at 54 and 66 weeks of age. Results of this study indicated that adding zinc to diet (T2, T3 and T4) resulted in significant (p<0.05) increase respecting blood plasma concentrations of estrogen and progesterone hormones during 54 and 66 weeks of age as compared with control group (T1). However, dietary supplementation with zinc (T2, T3 and T4) caused significant (p<0.05) increase concerning blood plasma concentration of testosterone hormone at 54, 58 and 66 weeks of age and as regards the overall means of this hormone in comparison with control group. In conclusion feeding diet containing zinc resulted in significant improvement respecting sex hormones (testosterone, estrogen, progesterone). Therefore, adding ration with zinc can be used as a beneficial tool for improving reproductive performance of broiler breeder chicken.