emale sex inversion as a reason for an unbalanced sex ratio in the neotropical species Brycon orbignyanu

Author(s)

Quirino, Patricia Postingel ^{[1, 2]} ; Ribeiro Delgado, Maria Luiza ^{[1, 2]} ; Gomes-Silva, Luciane ^{[1, 2]} ; Benevente, Cristiane Fernanda ^{[1, 2]} ; Grigoli-Olivio, Maiara Luzia ^{[1, 3]} ; Bianchini, Barbara Correa ^[1] ; Ninhaus-Silveira, Alexandre ^{[1, 2, 3]} ; Verissimo-Silveira, Rosicleire ^{[1, 2, 3]}

Affiliation

^[1] UNESP Univ Estadual Paulista Julio de Mesquita Fi, Dept Biol & Zootecnia, LINEO Lab Neotrop Ichthyol, Campus Ilha Solteira, Rua Moncao 226, BR-15385000 Ilha Solteira, SP - Brazil

^[2] IBB UNESP Inst Biociencias Botucatu, Programa Posgrad Ciancias Biol Zool, Botucatu, SP - Brazil

^[3] FEIS UNESP Univ Estadual Paulista Julio de Mesqui, Programa Posgrad Ciencia & Tecnol Anim, Fac Engn Ilha Solteira, Ilha Solteira - Brazil

• Document type: Journal article
• Source: AQUACULTURE RESEARCH; v. 53, n. 5 DEC 2021.
• Web of Science Citations: 0

Abstract

The objective of this study was to temporally identify sex differentiation to morphologically characterize the formation of female and male germinal epithelium and verify the occurrence of the sex disproportion reported for this species in aquaculture. Specimens of Brycon orbignyanus cultivated in water recirculation systems with a constant temperature of 27 +/- 0.5 degrees C were used. Monthly samplings of B. orbignyanus (n = 15) were performed from two months of age until 1 year of age, and posteriorly isolated sampling was performed on specimens of two and three years of age. The gonads of the specimens were removed and processed for light microscopy. In the beginning, the undifferentiated gonads develop into ovaries (females; at three months of age) and functional testicles (primary males; at five months of age); however, some of the females go through a sex inversion process creating intersex individuals and posteriorly secondary males (at five months of age). Due to the processes of sex inversion and gonadal remodelling, the population sex proportion fluctuates until it is finally established at 1 female:2 male. Females above 15 cm are differentiated, while in males (primary and secondary), differentiation will only occur after the animal reaches 20 cm. At the end of the first year of age, primary males and secondary males reach sexual maturity, while female sexual maturity is only observed at three years of age. (AU)

• FAPESP's process: 13/24527-8 - Histological and stereological evaluation of Astyanax altiparanae (Characiformes, Characidae) spermatogenesis
• Grantee: Maira da Silva Rodrigues
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 14/23379-8 - Xenogenic transplantation of spermatogonial stem cells in Characidae (Teleostei, Characiformes)
• Grantee: Rosicleire Veríssimo Silveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/27406-3 - Secondary sex characteristic in Brycon orbignyanus (Characiformes: Bryconidae) and its association with testicular development
• Grantee: Bárbara Correa Bianchini
• Support Opportunities: Scholarships in Brazil - Scientific Initiation