Improvement
of common carp artificial reproduction using enzyme for elimination of egg
stickiness
O.
Linhart, M. Rodina, D. Gela, M. Kocour, M. Rodriguez-2003
Abstract:
This study summarizes optimization of techniques for
common carp artificial propagation including improvements of activation
solution (AS), the process of insemination, and elimination of egg
stickiness. The optimum gamete ratio for good fertilization and hatching
rate ranged from 8490 to 23672 spermatozoa per egg, when
dechlorinated tap water was used. Optimal ratio between eggs (weight in g)
and AS (in ml) was defined as 1:1 to 1:2. Different concentrations of AS
such as NaCl from 0 to 34 mM (0–68 mOsmol kg–1)
did not change fertilization and hatching rates. An AS adopted for carp
spermatozoa (45 mM NaCl, 5 mM KCl, 30 mM Tris–HCl, pH 8)
was compared with other saline AS; only the 51 mM (102 mOsmol kg–1)
NaCl solution decreased fertilization and hatching rate. The AS containing
20 mM Tris–HCl at pH 9 increased fertilization and hatching
rates compared to dechlorinated tap water of pH 7 or to AS of pH 6 and
7. Adhesiveness from the eggs was successfully removed by incubation in
Alcalase DX (PLN 04715) using two successive steps with different enzyme
concentrations. The first step with an enzyme concentration of 2 ml l–1
was applied from 8 to 20 min after fertilization. Later in a
second step, the best time for application of alcalase enzyme at a
concentration of 20 ml l–1 was for 45 and 60 s
at 20 min after fertilization leading to fertilization and hatching
rates of 80–87%. The α-Chymotrypsin (EC 3.4.21.1. Merck) was also found
effective for elimination of stickiness. Results with α-Chymotrypsin
enzyme indicate that the response to success in elimination of stickiness is
highly variable mainly due to differences in the environment, quality of
water and carp strains.