Spermatozoa morphology and reproductive potential in F1 hybrids of common carp (Cyprinus carpio) and gibel carp (Carassius gibelio)

Sterility and semi-sterility often occur as a result of interspecific hybridization; however, the exact cause of sterility varies across the all animal kingdom; therefore, it is in the interest of scientists to examine every hybrid species separately. In the present study, the morphology of the spermatozoa of diploid F1 hybrids of Cyprinus carpio and Carassius gibelio was examined and compared with their parents. Hybrid spermatozoa showed great variability in head and flagellum lengths. These spermatozoa were diploid and triploid often with morphological abnormalities such as multiple flagella and nuclei. They were motile within two minutes after water activation which was almost two times longer than their parental species. We also analysed the reproductive output of F1 hybrids together with parental species in both parent positions via artificial spawning. Overall, the reproductive output of the hybrid x hybrid combination was the lowest; however, the hybrids were able to produce a small number of offspring documenting the viability of the F2 generation.