[Zbrafish] Unfertilized eggs

Irina V. Zhdanova zhdanova at bu.edu
Fri Aug 11 12:21:29 EST 2006


i assume you are getting the same messages from the ZFIN that I do.  Do 
you? If not, some are quite useful: see below

I took some of the suggestions I previously the, and it seems that our 
largest facility is back to normal.  The fish are laying great.  These are 
all our mutants.  However, the room where we keep our wildtypes as well as 
the larvae have stopped laying almost altogether.  For instance, last night 
I set up 24 tanks and 5 laid, which is well below what we have previously 
experienced.  Two of these clutches were unfertilized, and one consisted of 
12 eggs, and the other two were unhealthy.  This problem seems to be 
repeated on a daily basis.  The fish I set up have previously laid great 
clutches, even up to about a month ago.  Most were about a year old, though 
some were younger.  I set up WIKs, TLs, Nacres, and ABs.  The WIKs I didn't 
expect to lay that well.  I also set up 28 tanks in our quarantine room, 
and two laid, unfertilized clutches.  Again, they are pairs that previously 
laid well.  I am unsure the age of most, but at least 3 pairs were less 
than a year old.

All of our rooms are supplied with R.O. water from the same system.  We 
have an AHAB system, with 1L (between 1 and 4 fish), 2.75L (between 10 and 
20 fish) and 9L (up to 50 fish), but the density of fish in the tanks are 
about the same in both rooms.  We monitor the water quality with a YSI 
system.  The pH is generally around 6.8 and the conductivity between 300 
and 600.  The temperature in the main facility is about 28 degrees, while 
the wildtype room and the quarantine room are about 30 degrees (I know this 
is a high temp, but it has been consistently higher, so I am inclined to 
think that isn't the issue.)  I test the NH3, NO2 and NO3 once a week, and 
the nitrate is the only one that is ever elevated, and no more than 30 
ppm.  As far as I know, the town hasn't changed the method of treating the 
water (but both rooms use the same water).  The light cycle has an alarm so 
that we will know if they are staying on all night (we previously had that 
problem), plus people are som
etimes down there when the lights go out, so I am confident that is not the 
problem.  The only other difference between the two rooms is the 
lighting.  The main facility has lower lighting than the wildtype room, 
mainly because there are more racks arranged differently.  We feed Zeigler 
food in the morning and brine shrimp in the afternoon, but I think the 
breeding has improved since we switched to the Zeigler's.

Another thing that is making this frustrating is that when wildtype males 
are taken from that WT room to be bred with a mutant female in the main 
room, the eggs are almost always fertilized.  When WT are incrossed, more 
often than not whatever clutches are laid are unfertilized.  They are set 
up about once a week.  We do a lot of injecting in our lab and this is 
really starting to impact the research.  Any suggestions would be greatly 

I apologize for the length of this submission, but I hope that I have 
provided all the information one might need to know.  Thanks.

Heather McAllister
Research Specialist
Burdine Lab
Molecular Biology
Princeton University
Washington Rd.
Princeton, NJ 08544

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Irina V. Zhdanova, MD, Ph.D.
Associate Professor
Laboratory of Sleep and Circadian Physiology
Dept. Anatomy and Neurobiology
Boston University Medical School
715 Albany St. R-911
Boston, MA 02118-2394
zhdanova at bu.edu
Ph. (617) 638-8002 (office)
       (617) 638-4187 (lab)
FAX   (617) 638-4676

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