Characterization of sperm quality in Brycon hilarii: How does morphology affect sperm movement?

Brycon hilarii is a neotropical fish whose population in rivers is being threatened by overfishing, construction of hydroelectric dams, transposition of riverbeds, and pollution. Fundamental knowledge of the reproductive characteristics of this species is necessary to enable its breeding in captivity, for aquaculture as well as for biological conservation. The aim of this study was to investigate and describe the sperm parameters, their correlations, and relevant factors, and how these issues can affect sperm quality in B. hilarii. Sperm was collected after hormonal induction using carp pituitary homogenate. Spermatozoa concentration, total length, motility, and percentage of normal cells were measured to be 2.85 × 109 cells mL−1, 40.28 µm, 68.1%, and 51.6%, respectively. Tail abnormalities were most frequent; however, head abnormalities were closely related to practically all sperm kinetic parameters. Present results suggest that these abnormalities affect motility and movement kinetics, and modifying the pattern of sperm cell movement, sinuosity of movement and vigor. The potential application of this study in aquaculture management of B. hilarii is crucial for the artificial reproduction of fish and represents a significant contribution to the knowledge of its reproductive biology, facilitating the reproduction of the species.