Some differences between carp (Cyprinus carpio) and African catfish (Clarias gariepinus) spermatozoa motility

Summary Sperm motility is one of the most important viability parameter and the major energy utilising process in spermatozoa of externally fertilising fish. The adenylate energy charge (AEC) express the balance between energy regenerating processes by glycolysis and the Krebs cycle and energy utilizing processes including motility. In the present experiment, the AEC and sperm motility of African catfish (Clarias gariepinus) and carp (Cyprinus carpio) were compared during 24 h incubation in the presence of glycine as energy substrate. Carp spermatozoa showed remarkable capability in maintaining the AEC and preventing it from falling below the range of 0.9 over 24 h. In contrast, AEC in African catfish spermatozoa kept in the same incubation medium for 24 h fell down by about 20%. The intensity and the duration of the movement were much more higher in carp than in catfish spermatozoa. The results indicate significant differences between African catfish and carp spermatozoa as far as energy metabolism and motility are concerned. Moreover, the results presented here indicate tight association between AEC and fish spermatozoa motility.