[Zbrafish] obtaining eggs and sperm

wratzan from uchc.edu via zbrafish%40net.bio.net (by wratzan from uchc.edu)
Thu May 10 17:05:49 EST 2007

Hello zebra fish community!

I am new to working with danio rerio and I am trying to conduct some
experiments which will involve in vitro fertilisation.  Today I
manually expressed eggs and sperm for the first time.  I was
successful at both, but the eggs were very small (250 micron diameter)
and did not fertilise.  Furthermore, a few of the females ovulated
groups of similarly immature oocytes in the holding tank on their
own.  Has anyone seen this before?  Do you know what could be the
reason for the immature oocytes?  What can I do to rectify this?

The only thing I could think of is that it is that the lights go on in
the room four hours before the aquarium light and that some ambient
room light is leaking into the top of the tank through the cut-outs
where the filtered water pours into the tank.  I started collecting
gametes just before the aquarium light was about to go on.

The water is at 200 uS conductivity (by adding sodium bicarb and sea
salts and HCl to pH 7.6, 1 drop of methelyne blue per gallon).  The
fish were purchased from Carolina Biological about two months ago, and
about ten males and ten females were mixed in the same 5 gallon tank
together ten days ago.  I feed them flake food and live brine shirmp
evey day, and they are on a 14 hours of light to 10 hours dark cycle.

Thanks in advance for any suggestions

-William Ratzan
University of Connecticut Health Center
(860) 679 2677
wratzan from uchc.edu

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