A study was conducted to test the viability of the milt of the African catfish Clarias gariepinus following extension in citrated egg yolk extender and stored in a deep freezer at -20oC. Two male brood stocks of Clarias gariepinus with average age of 14 months, average weight 1.5kg and average measurement of 41.5cm length were used. The experiment comprised of two groups via the test and control groups. The test group consisted of seven milt samples extended in citrated egg yolk extender and stored in deep freezer at -20oC while the control group consisted of seven milt samples diluted in 2.9% sodium citrate solution and stored in the fridge at 4oC. Both the test and control groups were stored for seven days and the milt samples were examined daily for percentage motility, percentage live and mass activity. Results showed that motility persisted in both groups up to day seven of the experiment with the test and control having motility of 10% and 20%, percentage live of 10% and 20% and mass activity of + (1) and +(1) respectively as at day seven. There was no statistically significant difference between the mean motility, mean percentage live and mean mass activity of the two groups. The mean percentage motility for the test and control groups were 41.43Â±68 and 48.57Â±65 respectively, mean percentage live were 41.42Â±68 and 48.57Â±65 respectively and mean mass activity were 1.86Â±08 and 2.00Â±10 respectively. It was concluded that citrated egg yolk extender at -20oC was suitable for short term storage of the milt. It was recommended that optimum cryoprotectant agents be established. It was also recommended that field trials be involved to test fertilizability and hatchability after such storage.
Keywords: Citrated egg yolk, Milt, Extender, Catfish