Ovarian lavage method as an alternative route for hormonal administration and short-term sperm storage in Clarias...

Ovarian lavage is a term used to describe the injection of fish with a catheter through the oviduct into the ovary. In this study, the efficacy of this technique was evaluated as a route for hormone administration and sperm preservation in the African catfish Clarias gariepinus. Firstly, the effects of hormone injection routes (namely, intramuscular, intraperitoneal, and ovarian lavage) were evaluated on breeding and haematological parameters. In the second study, the fish's spermatozoa were stored in the ovaries for 1, 2, 3, and 4 days before stripping, sperm activation with freshwater, and fertilization. The breeding performance was then compared with eggs fertilized using spermatozoa refrigerated for the same duration. The study showed that the administration of synthetic hormone (ovaprim®) through the ovaries was comparable to the intramuscular route, while those injected intraperitoneally had the least values (P < 0.05) for breeding performance. The trend of the haematological parameters also suggests the intraperitoneal administration procedure elicited more stress compared to intramuscular or ovarian lavage routes (P < 0.05). In the second experiment, the use of sperm stored in the ovaries or refrigerated for 24hr didn't affect (P > 0.05) the fertilization (92-93%) and hatching (81-83%) of the eggs when compared to the control (91% and 82%). Beyond this 24hr threshold, breeding performances were significantly reduced in the ovarian lavage treatments compared to those fertilized with refrigerated sperm (P < 0.05). The loss of fertilizing capacity observed herein was justified by the reduction in sperm quality over time (P < 0.05). It was concluded that ovarian lavage is a viable route for hormonal administration and 24hr sperm storage in C. gariepinus.