Optimization of artificial propagation in European catfish, Silurus glanis L

The present work optimizes procedures for artificial insemination of European catfish, Silurus glanis L., with goals to increase collection of sperm and hatching rate. We address technical aspects of immobilizing solution (IS), activation solution (AS), process of insemination, activation of gametes and elimination of eggs stickiness with a practical solution for artificial propagation in hatcheries. Spermiation was stimulated and could be sustained over a period of 1 month after weekly carp pituitary (CP) injection of 5 mg kg −1 b.w. Males produced significantly the largest quantity of sperm, 0.12–0.13·10 9 spermatozoa kg −1 b.w., after third and fourth injections. The best IS for sperm was determined as solution containing 170–200 mM NaCl, 30 mM Tris–HCl, pH 7 and activation solution for activation of gametes containing 17 mM NaCl, 5 mM Tris–HCl, pH 7. The ratio of 1:2 rather than ratio of 1:1 in the control batch (volume of activation solution in milliliters/grams of eggs) increased the hatchability up to 68%. The highest hatching success of 82–88% from four individual females were found for sperm number of 800–80,000 spermatozoa egg −1 , in comparison to 26% hatching at 80 spermatozoa egg −1 . The best time for application of alcalase enzyme for elimination of egg stickiness was 3 min after gamete activation at concentration of 20 ml enzyme l −1 with exposure of 2 min.