Study on the effect of aromatase inhibitors and antiestrogens on the sex differentiation of broiler chicks

During the development of chick embryo, the genotype of the zygote determines the nature of the gonads, which thereafter creates the male or female phenotype. Differentiation of gonads during the period called “critical period for sexual differentiation “is accompanied with beginning of secretion of sexual hormones. Every change in the rate of steroidal hormones concentration during this critical period, affects on the structure of gonads. Therefore, injection of aromatase inhibitors (which blocks the synthesis of estrogen from testostron) in 5th day of incubation into the eggs, causes the production of males with female genotype. These sex reversal females have bilateral testes with complete spermatogenesis, having normal physical appearance and behavior. In this study, 14-α-hydroxy 3,6,17, androstan-trion inhibitor (1mg/egg) was injected into the eggs. Furthermore, the effect of three anti-estrogens (which blocks the estrogen receptor) Tamoxifen, and Clomiphen Citrate and GAR79 were studied. Injection of aromatase inhibitors into the eggs during incubation period caused statistically significant (p