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.