Relationship between seminal plasma composition and sperm quality parameters of the catfish Pseudoplatystoma reticulatum

Sperm quality is a fundamental parameter for the effective reproduction of fish in captivity and the development of reproductive techniques, such as semen cryopreservation. This study aimed to determine the composition of the seminal plasma of Pseudoplatystoma reticulatum and analyze the relationships between plasma components and sperm characteristics. Nine males were induced to spermiation with carp pituitary extract in the reproductive period of the species (November and December/2019). Semen characteristics were evaluated: subjective sperm motility, motility, duration, released sperm volume, sperm concentration, pH, osmolality, and seminal plasma composition, including levels of calcium, chloride, sodium, magnesium, potassium, glucose, fructosamine, triglycerides, and total protein. To determine the relationship between seminal plasma components and sperm motility parameters, a principal component analysis (PCA) was performed. The seminal plasma of P. reticulatum is composed mainly of the Na+ ion and organic components such as protein and glucose. Through PCA, it was observed that sperm motility had a strong positive correlation with motility time, sperm concentration, and total protein and a negative correlation with osmolality and fructosamine.