2.
Collection of the Male's
Sperms. The sperms
of the male koi is retrieved through a similar manner of hand
stripping, except that the milt is usually collected in a glass
beaker. Alternatively, a glass bottle with a large mouth may be used. Again, wipe the male koi until it is dry before
squeezing its belly and letting the milt fall into a glass beaker.
Another method for extracting milt is through the use of a plastic
syringe, which can conveniently and cleanly suck the milt out of the
male koi. The milt collected by the syringe can then be easily
transferred into a glass container.
Dilute the milt with 0.9 NaCl solution at a ratio of 3 parts saline
solution for every part of milt. The same procedures for
retrieving the milt can be
applied to additional male koi if genes from different male koi are
desired for the fertilization of the eggs.
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Figure 3.
The milt of a male koi may be retrieved using a plastic
syringe and collected in a glass bottle. |
3.
Mixing of Eggs and Sperms.
Once the milt of the male koi have been collected and diluted, the
solution can be poured directly into the eggs inside the bowl.
This causes the sperms of the male koi to fertilize the eggs
of the female koi.
The fertilization can be made more effective by gently mixing the
mixture by hand using a large plastic spoon.
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Figure 4.
The milt of the male koi is mixed well with the eggs of the
female koi to maximize fertilization. |
4.
Degumming.
Degumming is the process of removing the stickiness of the
fertilized eggs. Koi eggs are by nature sticky to allow them
to adhere to surfaces for incubation after natural spawning.
This stickiness needs to be eliminated when the fertilized eggs are
to be hatched inside artificial incubators that employ running
water. Otherwise, the sticky eggs will form clumps inside such
incubators.
Degumming is achieved by
rinsing the eggs with three different solutions done in succession.
The first rinse is 4-5 minutes of continuous mixing with a
Woynarovich fertilization solution (3 g NaCl, 4 g Urea, 1 L water).
The second rinse is one hour long and uses a modified Woynarovich
solution (3 g NaCl, 20 g Urea, 1 L water). This second rinse
requires that the eggs be mixed only every 10 minutes, with the
rinsing solution being replaced with a fresh one after each mixing.
The third and last rinse, which is done to harden the egg shell,
is just a quick one (a few seconds) with tannic acid solution (1 g
tannin, 1 L water) to be followed by a washing with water.
5.
Incubation.
After degumming, the non-sticky eggs can then be placed in
artificial egg
incubators without the problem of egg clumping.
A word of caution though - the
procedures discussed above require a high level of skill and should
not be tried by a novice on expensive koi (or any koi for that
matter). In fact, even expert breeders prefer to let their
expensive koi spawn naturally instead of hand-stripping them of
their gametes. The article above only presents what the dry method
of fertilization is and is not a guide to be followed for an actual
operation. It must be emphasized that improper
hand-stripping can cause damage to the koi being stripped.
See also:
Basic Koi Breeding;
Koi Breeding Considerations
