Crecimiento y calidad espermática en trucha arcoíris Oncorhynchus mykiss (Teleostei: Salmonidae) durante la temporada reproductiva

Background. Oncorhynchus mykiss is a species that is widely cultivated in the world with high economic value. For this reason, it is essential to optimize its growth and reproduction for aquaculture. Goals. Evaluate the growth and sperm quality of rainbow trout during the reproductive season. Methods. We conducted research at the “El Zarco” Aquaculture Center in the state of Mexico, with 32 sexually mature three-year-old males. Once a month, we recorded total length, height, thickness (cm), and weight (g) during July-February, and calculated weight gain (WG), absolute growth rate (AGR), and instantaneous growth rate (IGR). Semen samples were obtained during (August-February). In order to evaluate the spermatic quality, we measured volume, color, consistency, concentration, pH, and mobility. Results. The highest AGR, WG, and IGR in terms of length and weight were obtained from July-August, i.e., a month prior to the reproductive period; from August-February the AGR was 1.13 cm, WG was 0.01 g, and there was an average IGR of 0.0321 ± 0.0522 cm and 0.0932 ± 0.2223 g. Differences (p <0.05) in length and weight were found between July and the months of the reproductive period. There was a pattern of semen production: It increased from August to October and then decreased until February, with significant differences (p <0.05). Usually, white semen and milky consistency were found. The highest sperm concentration occurred in September (8.17 ± 2.06 x 109 mL-1) and decreased until February, with significant differences (p <0.05) between months. The pH was alkaline with an average value of 8.07 ± 0.31. Mobility increased from August to December and decreased from January to February, with significant differences (p <0.05) between months. Conclusions. During the reproductive period, food energy is channeled to ensure reproduction, so that growth slows and sperm quality varies during the reproductive months.