The applicability of large-scale sperm cryopreservation in wels catfish (Silurus glanis) optimized for hatchery practice

Abstract In the presented study, effects of sperm cryopreservation methods (Polystyrene box-P. box vs a controlled-rate freezer-CRF) and various semen confection methods during freezing (5 mL straw vs. 10 mL cryotube) on sperm motility parameters and fertilization capacity of wels catfish ( Silurus glanis ) were tested. In general, pMOT (Control: 89 ± 3%, Straw P. box: 50 ± 9%, Straw CRF: 53 ± 12%, Cryotube: 52 ± 7%) and BCF (Control: 30 ± 1 Hz, Straw P. box: 27 ± 1 Hz, Straw CRF: 26 ± 1 Hz, Cryotube: 27 ± 1 Hz) showed significant reduction following thawing. ALH reduced significantly in the case of the straw frozen with P. box (1.2 ± 0.2 μm) compared to the fresh control (1.5 ± 0.1 μm). However, VCL (Control: 108 ± 6 μm/s, Straw P. box: 107 ± 5 μm/s, Straw CRF: 108 ± 8 μm/s, Cryotube: 109 ± 7 μm/s) and VSL (Control: 94 ± 6 μm/s, Straw P. box: 99 ± 4 μm/s, Straw CRF: 99 ± 9 μm/s, Cryotube: 99 ± 7 μm/s) did not decrease. A significantly higher LIN was measured using the straw cryopreserved in the P. box (92 ± 2%) and the CRF (91 ± 2%) in comparison with the fresh control (86 ± 1%). No significant difference in the fertilization capacity when eggs were fertilized by frozen/thawed (Straw P. box: 75 ± 5%, Straw CRF: 72 ± 3%, Cryotube: 66 ± 6%) or fresh (control, 68 ± 4%) semen was observed ( P  > .05). As well, no significant correlation between none of sperm motility parameters tested and the fertilization rate were recorded ( P  > .05). All tested sperm cryopreservation showed a similar high efficiency in the hatchery practice of wels catfis.