Large-scale cryopreservation affects sperm characteristics and hatching rate but not growth, malformation and survival rate in chub (Squalius cephalus) larvae

The objective of this study was to investigate the growth, malformation and survival rate in chub ( Squalius cephalus ) larvae originating from large-scale cryopreserved sperm. Sperm was cryopreserved in accordance with a protocol (modified extender designed for northern pike, 10 % methanol, 1:1, 4 mL cryotube, Styrofoam box) previously developed in our laboratory. Firstly, the motility and different kinetic parameters (fresh, control, cryopreserved) of sperm (control and cryopreserved) used for propagation, and the hatching rate were evaluated. Secondly, the growth (average body weight, total length), malformation and survival rate were assessed in a 12-day rearing experiment (0, 8, 12 days post-hatching - DPH) by the larvae originating from control and cryopreserved sperm. A significantly lower motility (MOT), progressive motility (pMOT), and linearity (LIN) were recorded in the cryopreserved group compared to the fresh and control groups. The distance average path (DAP), curvilinear velocity (VCL), straight line velocity (VSL), beat cross frequency (BCF) showed significant differences in all three groups. The control group (96 ± 1 %) exhibited a significantly higher hatching rate in comparison with the cryopreserved group (70 ± 14 %). Sperm cryopreservation had no major negative effect on the growth (except only in total length at 0 DPH), malformation and survival rate of chub larvae. Extending the study period to encompass the complete pre-nursing or grow-out periods in future research would be beneficial. • A significantly lower MOT, pMOT, and LIN were recorded in frozen sperm. • A high hatching rate was measured in the cryopreserved group (70 ± 14 %). • Sperm cryopreservation has no major negative effect on growth rate of chub larvae. • A similar malformation and survival rate was detected in control and frozen groups.