Influence of freezing temperature on semen quality of rainbow trout (Oncorhynchus mykiss)

Trout production in Peru has export potential. However, there are no fry available to maintain production throughout the year and there is also a lack of egg production at certain times of the year. Therefore, the alternative is to cryopreserve semen for the non-reproductive season. The objective of the study was to determine the influence of freezing temperature on the quality of rainbow trout semen. The semen of 12 reproductive males was collected in the facilities of the Chucuito Research and Production Center of the National University of the Altiplano of Puno, which underwent a macroscopic, microscopic pre and post thaw seminal evaluation and the fertility rate was measured. Due to the effect of three freezing temperatures (-80 °C, -100 °C, -120 °C), cryopreservation had a decline curve of -20 °C / min. The fresh seminal parameters were similar to those reported by other researchers. While freezing had unfavorable effects on semen quality, the best results for activation time (51.33 sec) and vitality (35.33%) were obtained with -100 °C, but the higher motility was obtained with -120 °C (36.33%). Regarding fertility, the higher rate was obtained with -100 °C (70.97%), followed by -80 °C and -120 °C in which 68.86% and 64.34% were obtained, respectively. In conclusion, the results suggest that the tolerable freezing temperature of rainbow trout semen is around -100 °C, which is shown as a favorable alternative for the reproductive management of rainbow trout under natural hypobaric conditions of the Peruvian highlands