title: Degree of sex differentiation of genetic female chicken treated with different doses of an aromatase inhibitor.
abstract: Injection of an aromatase inhibitor before gonadal sex differentiation can induce female-to-male sex reversal in chicken, but a higher dose could reduce hatchability. In the present study, the dosage effect of Fadrozole, a nonsteroidal aromatase inhibitor, on gonadal differentiation was analyzed in sex-reversed genetic female chicken. There was no significant difference for the hatchability among low-dose (0.1, 0.3 and 0.5 mg) Fadrozole-injected groups and control groups (p > 0.05), but in high-dose groups (1.0 mg and 1.3 mg) the hatchability was significantly reduced (p < 0.05). Complete phenotypic sex reversal was observed in both high- and low- dose groups, with more than 90% of genetic females reversed into phenotypic male chicks. The degree of gonadal differentiation in 124 chicken at 30 weeks of age was classified into 5 categories according to the visual appearance and histological structure of the gonads. Category I and V were standard ovary and testis, respectively, while category II, III, and IV represented gonads of slightly, moderately, and highly sex-reversed females, respectively. Most gonads in low-dose groups were classified into category I, II, and III, while those in high-dose groups were mainly category IV. The serum testosterone levels in the 1.3 mg group were significantly higher and the estradiol levels lower than those in low-dose groups (p < 0.05). In conclusion, the range from 0.5 to 1.0 mg Fadrozole is a key interval for survival of chicken embryos. The gonadal differentiation in sex-reversed females at 30 weeks of age is highly dependent on the dose of Fadrozole injected prior to gonadal sex differentiation.
authors.affiliation: State Key Laboratory for Agrobiotechnology and Department of Animal Genetics and Breeding, China Agricultural University, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: J
authors.initials: J
authors.lastname: Zheng
authors.forename: R
authors.initials: R
authors.lastname: Na
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Qu
authors.forename: N
authors.initials: N
authors.lastname: Yang
mesh_terms: D000818:Animals; D047072:Aromatase Inhibitors / Q000633:toxicity*; D002642:Chick Embryo; D002645:Chickens / Q000502:physiology*; D012734:Disorders of Sex Development; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000097:blood; D005260:Female; D005838:Genotype; D008297:Male; D010641:Phenotype; D012671:Seminiferous Tubules / Q000187:drug effects / Q000254:growth & development; D019849:Sex Determination Processes; D012733:Sex Differentiation / Q000187:drug effects* / Q000235:genetics*; D013739:Testosterone / Q000097:blood
chemical_list: D047072:Aromatase Inhibitors; D013739:Testosterone; D004958:Estradiol