Zebrafish maintenance in laboratory


Fri May 14 08:40:00 EST 2004


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Sabrina,

As the author of the statements about density, I might elaborate a bit. 
The amount of water exchange is determined by the % removal of pollutants
in the filer system per pass through the filter system (how good is the
water you are putting back in the tanks) and the desired operating ammonia
and oxygen levels (assuming you have not nitrite in the filtered water). 
I like to keep the DO (dissolved oxygen)  5+ ppm and the total ammonia
(TAN) below 0.3 ppm.  A 90% removal system like the large fluidized bed
systems from Aquaneering (For example, the University of Oregon system or
my systems) needs half the exchange rate of a 45% removal system.

The amount of oxygen consumed and the rate of ammonia production by the
fish is intern related to the feed rate -- feed in, waste out.  This is
why the total feed rate in kg/day is a very important system design
variable.

The social limits on density with zebra fish are a function of age. 
Larval fish appear to be limited by the #/cm2 (depends upon the strain --
my fish have problems above about 5/cm2 in 1000 l tanks), whereas the
adults are more a #/liter or kg/m3 type animals, which do fine in the 20
to 50 gm of fish/ liter range (it all depends upon the size of the fish --
about 100+/l small adults and 50/liter very large).  As you get into the
100+/l range, you can also get into feed distribution problems, where the
larger fish get all the feed and you get a growth rate variation.

For breeding, I like to drop the density down into the < 10/l range. 
Above that range, you seem to get more infertile or non-viable eggs as
unripe females get their eggs expressed.

Dallas


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