The application of tannic acid to the elimination of egg stickiness at varied moments of the egg swelling process in pikeperch, Sander lucioperca (L.)
Résumé
The aim of this article was to analyse the process of pikeperch, Sander lucioperca, egg swelling and to apply tannic acid to eliminate egg stickiness at different moments of the swelling process on artificially obtained eggs. The first experiment involved observation of egg swelling process and the second determined the effect of temperature (12, 14 and 16 degrees C) on the egg swelling rate. The third experiment involved elimination of egg stickiness in a tannin solution (0.75gL(-1)) where eggs were submerged in a solution for 0.5, 1, 2 and 5min - 5, 10, 15, 20, 25 and 30min following gamete activation. The results indicate that the pikeperch egg swelling process lasts 30min. It was found that the temperature did not affect the process duration. The results of the third experiment showed that the effectiveness of tannic acid application in egg stickiness elimination increases with time. The best result was obtained in groups of eggs submerged for 1 and 2min (86.5% and 80.5% of larvae were obtained respectively) 30min following the gamete activation. The results presented in this study for the first time indicate the possibility of highly effective procedure of egg stickiness elimination with tannic acid in pikeperch aquaculture.