[Zbrafish] Mass Embryo Rearing

Judy Bennett via zbrafish%40net.bio.net (by jbennett from bio.umass.edu)
Thu May 3 09:12:03 EST 2007

Hi Doreen,

I'm assuming you're asking about mass matings to produce embryos....

We use this system with our wild types and it works out very well.

-We have eight 9L tanks (AHAB system), stocked at around 40-50.
-I try to stock a few more females so it's not quite a 1:1 ratio.
-I also try to stock tanks with fish that aren't all siblings, which 
I believe increases amount and length of production.
-The tanks are set up once every two weeks starting Monday night, so 
we have embryos Tues-Fri (hence the 8 tanks).
-We do have a few "extra" tanks to set up if there is a need for a 
large number of embryos.
-The trays we use are homemade, but basically consist of a frame with 
a large mesh covering the top and a small mesh covering the 
bottom.  We usually attach some artificial grass and insert it at an 
angle creating a shallow area.
-These tanks get an extra feeding of dry food (ZIRC recipe) during 
the week as well.
-I keep track of the amount laid with a 0-5 scale.  5, being the 
best, would mean the tank laid for several hours and produced several 
hundred/hour.  If you want 50,000 daily you will probably need to set 
up more than one of this type/size tank.
-When a tank starts to decline in production, I stock another tank to 
replace it.  I've had a few tanks produce well for over a year, but 
this can vary.
-I will use embryos from these mass matings to raise up and replace 
our WT stock, but also raise embryos from pair crosses.  Again, since 
I combine unrelated fish in these mass mating tanks, and collect eggs 
throughout the day/week, I believe this helps avoid 
inbreeding...(that's another topic in itself that I think was 
discussed recently).

-When mutant lines are not producing in pair crosses, I have the lab 
set them up in this style and they will lay within one or two 
times.  (Better odds of compatible couples?)

I hope this helps and isn't too confusing.  Feel free to ask if you 
have any other questions.

Judy Bennett
UMass Amherst

At 03:34 PM 5/2/07, Doreen wrote:
>I am interested to hear of other facilities experience with the mass
>raising of wild type embryos.  What worked or didn't work?  Volume and
>shape of tanks?  Stocking density?  Harvesting method?  Daily egg
>production achieved?  Method of breeder replacement?  Our current
>estimate/goal for daily production is 50,000 embryos.
>Thank you!
>Zbrafish mailing list
>Zbrafish from net.bio.net

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