title: Early sexing techniques in Lophiosilurus alexandri (Steindachner, 1876), a freshwater carnivorous catfish.
abstract: This study aimed to evaluate sexing techniques for juvenile Lophiosilurus alexandri. With this aim, we evaluated three techniques: coelioscopy, performed with the use of video surgery equipment; coeliotomy, a surgical procedure for direct visualization of the gonads; and sex determination using a urethral probe to compare the genital papillae. For coelioscopy, the survival rate was 100% 30 days after the procedure, and the fish restarted eating 10 days after surgery. This technique resulted in a 100% correct identification of individuals identified as females, whereas for males, it was 66.6%. There was no significant difference between males and females for anesthesia induction and recovery times. However, the procedure took longer for males because of the difficulty in observing the gonads, which can be attributed to the large amount of visceral fat in males. Coeliotomy also resulted in a 100% survival rate 30 days after surgery, and the efficiency of this technique was 96.3% for males and 93.9% for females. The fish restarted eating between 10 and 14 days after surgery, and there were no significant differences between males and females for anesthesia induction and recovery times for the surgical procedure to visualize the gonads (P > 0.05). The urethral probe technique was less efficient with an accuracy rate of 67.8% and 81.8% for males and females, respectively. We conclude that coeliotomy was more efficient for sexing both sexes of juvenile L. alexandri.
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Melillo Filho
authors.affiliation: Laboratório de Obstetrícia Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Valentim Arabicano
authors.initials: VA
authors.lastname: Gheller
authors.affiliation: Centro Universitário de Formiga, UNIFOR-MG, Formiga, Minas Gerais, Brazil.
authors.forename: Glauco Vinício
authors.initials: GV
authors.lastname: Chaves
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Walisson
authors.initials: W
authors.lastname: de Souza E Silva
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Deliane Cristina
authors.initials: DC
authors.lastname: Costa
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Luis Gustavo
authors.initials: LG
authors.lastname: Figueiredo
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Gustavo Soares
authors.initials: GS
authors.lastname: da Costa Julio
authors.affiliation: Laboratório de Aquacultura, Departamento de Zootecnia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: luzrk@yahoo.com.
authors.forename: Ronald Kennedy
authors.initials: RK
authors.lastname: Luz
mesh_terms: D000818:Animals; D001699:Biometry; D002397:Catfishes / Q000601:surgery; D002404:Catheterization / Q000379:methods / Q000662:veterinary; D005260:Female; D005618:Fresh Water; D006066:Gonads / Q000033:anatomy & histology; D010535:Laparoscopy / Q000379:methods / Q000662:veterinary; D008297:Male; D012732:Sex Determination Analysis / Q000379:methods / Q000662:veterinary*; D014521:Urethra
keywords: Carnivorous fish; Pacamã; Reproduction; Sexing; Surgery in fish