title: Spermatozoon ultrastructure and semen parameters of Brycon vermelha (Characiformes, Characidae).
abstract: This study analyzed semen parameters and the ultrastructure of spermatozoa of Brycon vermelha. The semen was white and viscous, with a mean volume of 5.0±2.6 mL/kg body weight and mean spermatozoon concentration of 4.3±0.8×10(10) spermatozoa/mL. The estimated motility rate was 90%, with 50% of spermatozoa motile at 35.0±0.1 s and 100% immotile by 46.5±0.1 s. The spermatozoon of B. vermelha had a distinct head, midpiece, and flagellum. The ovoid head measured 1.9±0.2 μm by 1.3±0.1 μm, with its volume almost completely occupied by the nucleus, and was enveloped by an irregular nuclear membrane, with no acrosome vesicle. The nuclear fossa held the centriole complex and the initial segment of flagellum. The midpiece was symmetrical and measured 1.3±0.3μm. Mitochondria were scarce and restricted to the anterior region, while vesicles were absent. The posterior region of the midpiece was characterized by the absence of mitochondria and the presence of the cytoplasmic sheath. The flagellum, enclosed by the flagellar membrane, measured 29.6±3.4 μm, and possessed an axial filament containing a 9+2 microtubule pattern. The spermatozoa of B. vermelha appeared similar in structure to those of fish that breed through external fertilization, thus classifying them as uniflagellate anacrosomal aquasperm, or Type 1 aquasperm.
authors.affiliation: Centro de Aquicultura da Universidade Estadual Paulista (CAUNESP), Jaboticabal, São Paulo, Brazil. Electronic address: francine.unesp@gmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Faustino
authors.affiliation: Centro de Aquicultura da Universidade Estadual Paulista (CAUNESP), Jaboticabal, São Paulo, Brazil. Electronic address: regianesilva_bio@yahoo.com.br.
authors.forename: R C
authors.initials: RC
authors.lastname: Silva
authors.affiliation: Centro de Aquicultura da Universidade Estadual Paulista (CAUNESP), Jaboticabal, São Paulo, Brazil. Electronic address: cleonicehilbig@yahoo.com.br.
authors.forename: C C
authors.initials: CC
authors.lastname: Hilbig
authors.affiliation: Campus Experimental de Registro, Universidade Estadual Paulista - UNESP, Registro, São Paulo, Brazil. Electronic address: lilianmakino@registro.unesp.br.
authors.forename: L C
authors.initials: LC
authors.lastname: Makino
authors.affiliation: Centro de Pesquisa e Gestão de Recursos Pesqueiros Continentais, Instituto Chico Mendes de Conservação da Biodiversidade, CEPTA/ICMBio, Pirassununga, São Paulo, Brazil. Electronic address: jose.senhorini@icmbio.gov.br.
authors.forename: J A
authors.initials: JA
authors.lastname: Senhorini
authors.affiliation: Centro de Aquicultura da Universidade Estadual Paulista (CAUNESP), Jaboticabal, São Paulo, Brazil; Departamento de Biologia e Zootecnia, Faculdade de Engenharia, Universidade Estadual Paulista - UNESP, Ilha Solteira, São Paulo, Brazil. Electronic address: ninhaus@bio.feis.unesp.br.
authors.forename: A
authors.initials: A
authors.lastname: Ninhaus-Silveira
authors.affiliation: Centro de Aquicultura da Universidade Estadual Paulista (CAUNESP), Jaboticabal, São Paulo, Brazil; Departamento de Morfologia e Fisiologia Animal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista - UNESP, Jaboticabal, São Paulo, Brazil. Electronic address: laurankg@fcav.unesp.br.
authors.forename: L S O
authors.initials: LS
authors.lastname: Nakaghi
mesh_terms: D000818:Animals; D060126:Characidae / Q000502:physiology*; D008297:Male; D012661:Semen / Q000502:physiology*; D013094:Spermatozoa / Q000648:ultrastructure*
keywords: Fish; Reproductive biology; Semen; Spermatozoa; Ultrastructure