POLISH JOURNAL OF VETERINARY SCIENCES, cilt.28, sa.1, ss.159-164, 2025 (SCI-Expanded, Scopus)
Nile tilapia Oreochromis niloticus is a popular freshwater fish that has been extensively and intensively cultured worldwide. However, cryopreservation of its sperm, especially pre-freezing procedure, has not been properly developed. Therefore, the study aimed to determine the best pre-freezing procedure for cryopreservation of Nile tilapia Oreochromis niloticus sperm. The completely randomized design with five treatments and four replications was employed in this study. The tested treatments were T1=4 degrees C-* 0 degrees C-*-4 degrees C-*-10 degrees C-*-79 degrees C-*-196 degrees C, T2=4 degrees C-* 0 degrees C-*-4 degrees C-*-10 degrees C-*-196 degrees C, T3=4 degrees C-* 0 degrees C-*-4 degrees C-*-196 degrees C, T4=4 degrees C-* 0 degrees C-*-196 degrees C), and T5=4 degrees C-*-196 degrees C, with a 10 min equilibration at each respective temperature. Furthermore, sperm was cryopreserved for two weeks in liquid nitrogen (-179 oC). The results of the ANOVA test showed that pre-freezing had a significant effect on sperm motility, and viability (P<0.05), but had no considerable impact on sperm abnormality (P>0.05). Treatment T4 exhibited higher motility and viability, but these values were not significantly different from T3 and T5. Based on practical consideration, it was recommended to utilize the T5 pre-freezing procedures (4 degrees C-*-196 degrees C) for cryopreservation of Nile tilapia sperm. Considering these results, Nile tilapia sperm can be directly cryopreserved into liquid nitrogen after equilibration at 4 degrees C for 10 min.