Egg incubation time and hatching success in tench Tinca tinca
(L.) related to the procedure of egg stickiness elimination
D.
Gela, O. Linhart, M. Flajšhans, M. Rodina-2003
Journal of
Applied Ichthyology, 19(3): 132-133
Abstract:
The experiment showed different results
after a short (2 min) enzyme alcalase Merck EC 3.4.21.14 (5.0 ml L
-1
concentration) treatment of tench eggs in contrast to the traditional
methods of eliminating egg stickiness involving milk solution (50 g L
-1)
treatment for 70 min followed by the addition of a talc suspension (33 g L
-1)
for 10 min or treatment by fine clay suspension (20 g L
-1)
for 60 min or talc suspension (33 g L
-1)
for 80 min. The alcalase enzyme treatment resulted in decreased egg
stickiness compared with the conventional milk/clay/talc treatments,
indicated by lower duration of egg incubation and higher hatching rates (anova
for hatching rate, P < 0.0084). The highest hatching rate
(93.2%) was achieved using the enzyme; the lowest (31.3%) was using a talc
suspension (control hatching rate was 86.2%). Duration of egg incubation at
degree-days (D°) after enzyme treatment (58.6 D°) was about 4-5 h
shorter than the classical method using milk solution and talc suspension
(63-65 D°). Prolongation in the latter classical method may also be
explained by a hardening of the egg envelopes.
(University of South Bohemia, Research
Institute of Fish Culture and Hydrobiology, 389 25 Vodňany, Czech
Republic, e-mail of O. Lihnart: linhart@vurh.jcu.cz)