Study On Sexual Differentiation Induction Of Muscovy Duck Using Aromatase Inhibitors: Formestane And Letrozole

Muscovy duck is a kind of meat-type breed, which is characterized by large differencein body weight and production performance between male and female. Our hypothesis isthat if the embryo at early stage could be induced, the ratio of male to female can bechanged, which would be very useful in animal production. The sex gonad is dominated byreproductive hormone, for instance, sex gonad can develop into testis with the help ofandrogen hormone and ovarian by estrogen hormone.Previous research has demonstrated that the synthesis of estrogen was catalyzed fromandrogen by aromatase and aromatase is a key enzyme in estrogen synthesis. If the embryoof muscovy duck was treated with aromatase inhibitor before sex differentiation, the femalemuscovy in genetics may then go into male in phenotype.In the present study, a total of 320 breeding eggs were randomly divided into fourgroups: one for control group, the other three for experiment groups which were injected0.1ml sodium chloride, formestane (100 ug) and letrozole (100 ug), respectively. The sex ofmuscovy duckling were identified with artificial and molecular method in 24h after hatchedand the dissection of sex gonad were conducted to observe the change in structure andtissues.The results showed that the aromastase inhibitor apparently improved incubation rate,induce sex inversion as 16.67% for formestane group and 14.8% for letrozole group.Aromatase inhibitor also reduced hatching rate significantly for L group.According to W chromosome specific sequence and 18S gene, two pairs of primerswere designed to identify the sex in genetics. The morphology of male duck testicle wasdifferent from that of control group. The left testicle was larger than that of right one. Andpart of sex revertion muscovies had both histological structures, such as ovary-testclestructure. Thus, aromatase inhibitor could block the synthesis of estrogen at early stage ofembryo before sex differentiation, which then led the morphogenesis of estrogen go into theorentiation of androgen.