Sperm and egg in vitro storage effects on artificial fertilization and hatching in common carp (Cyprinus carpio L.)

This is the first report showing fertilization of short-term stored eggs (19 degrees C) with short-term stored diluted sperm (0-2 degrees C) in common carp (Cyprinus carpio). From 5 males, fresh (control) and 7-day stored sperm were diluted with common carp extender. After collection of eggs from nine females, the eggs were immediately pooled into three groups from females 1-3, 4-6 and 7-9, according to the eggs' quality based on visual criteria. They were placed in beakers, covered and incubated at 19 degrees C (for each pool, 10 g of eggs from each female were used). The 7-day short-term storage sperm was incubated at 20 degrees C for 20 min and pooled before being used for fertilization. The eggs were fertilized with fresh and short-term storage sperm after 1, 3 and 6 h post storage of eggs and activated with hatchery water and Perchec solution. Sperm motility and velocity (50-54% and 80-115 mu m/s) of 7-day short-term storage sperm at 0-2 degrees C were ensured by additional incubation of sperm at 20 degrees C for 20 min before being activated. Principal component analysis showed that the sorting of eggs of different females into three groups according to sperm quality, fertilization ability and production of malformed larvae was successful. It is recommended that overripe common carp eggs are stored for a maximum of 1 h. A period of 3 h can be used for better quality eggs and exceptionally, up to 6 h for very high-quality eggs. Higher larvae malformation was found in the 6 h aged eggs together with fertilized short-term storage and fresh sperm. In all quality groups of eggs, the effect of different sperm, activation medium and egg storage time on the level of malformations was observed. The activation solution for carp did not show any positive fertilization and hatching effects.