On raising Zebrafish larvae
chubbyjayu
I have been trying to raise zebrafish larvae in the lab
unsuccessfully. The problem is that the larvae tend to die 12 - 14
days post fertilization and there seems to be no logical cause for the
death.
I check the paramecium stocks for coleps everyday, but see none. We
have even tried raising the zebrafish larvae in embryo medium (made
as per the zebrafish book), but even then we see that the larvae die
out within 14 days.
Could you please help me figure out where I am going wrong?
Jayasree
finchg....@gmail.com
Jayasree,
Hopefully these pointers will be helpful.
Even using E3 the fish are going to need a gradual water change. Some
facilities put the babies on an overnight drip/trickle which is turned
off in the day.
When the fish are dying at 12-14 days, this usually indicates that
they are not getting enough to eat (I've been told the yolk runs out
around day 10).
In my experience fish do best with an extreme concentrations of
paramecia. You want the it too look like a paramecia blizzard in the
tank if you can. This is why using a small volume tank or beaker
(greater para. conc.) works best for the larvae.
If the fish are well fed you can see their bellies bulged out even
without magnification.
It seems to be nearly impossible to "overfeed" babies (of course
rotting food in the tank is a no-no, but this doesn't seem to happen
easily with para).
Hope this helps.
Lawrence, Christian
At 28C, they start exogenous feeding at 5 days, but also continue to derive nutritional benefit from the yolk sac, but this is generally gone by day 7. If you don't give them any food at all, they will starve at day 10 or so.
No matter how dense, standard, bacteria-fed Paramecium does not meet the considerable nutritional demands of the fish beyond the first few days of feeding. If you do not present the larvae with something else with a better nutritional profile (higher protein, and specific lipid content) at this point, they will starve. If all of your fish die by 12-14 days, then that is likely what is happening. The Paramecium typically gets them out a day or two longer than the 10 day mark. Even if you manage to keep them alive beyond that, they won't grow until you give them something with an adequate nutritional profile. You're just prolonging the starvation.
If you start feeding Paramecium at day 5 (as soon as they are swimming), you should be presenting them with another item, in small, frequent applications, whether it be first stage Artemia nauplii or a processed larval feed, by 7-9 days. Once you begin do this, you should put them on flow at a slow drip to maintain stable (but not necessarily pristine) water quality. Once it becomes apparent that they are feeding on the new items (full guts, rapid growth), you can stop the paramecium applications, increase the amounts of the new feed per feeding, and slowly increase flow rates as the fish grow.
The weaning from a low nutritional quality first feed like Paramecium to something better is the key to success in larval rearing. If you don't do it correctly or well, your survival rates will always be poor.
Chris
On 9/7/09 12:11 AM, "chubbyjayu" <chubb...@gmail.com> wrote:
Hello all!
I have been trying to raise zebrafish larvae in the lab
unsuccessfully. The problem is that the larvae tend to die 12 - 14
days post fertilization and there seems to be no logical cause for the
death.
I check the paramecium stocks for coleps everyday, but see none. We
have even tried raising the zebrafish larvae in embryo medium (made
as per the zebrafish book), but even then we see that the larvae die
out within 14 days.
Could you please help me figure out where I am going wrong?
Jayasree
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Claudia
if you have static tanks you need to change water twice a day and
remove uneaten food. Regular system water works just fine if you have
fungus problems add Fungus Eliminator to the water. Also we start
feeding a mix of Paramecium and Artemia starting 7dph. You can see our
detailed methods at http://www.cvm.msstate.edu/basic_sciences/faculty/petrie-hanson_lora.html
click on link zebrafish maintenance.
Hope this helps,
Claudia
Burdine, Rebecca D
We have had good luck with AZ100 and BioKyowa for fish 5-10 days old. We have used various sized Zeigler AP100 dry food for 10-30 days.
We typically get survival over 80% depending on the strain.
Becky
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Leviathan
rest assured that you are not alone in your struggle for efficiently
closing the life cycle of the zebrafish. There are many labs out
there that use a variety of different methods for rearing their very
young fish.
If you haven't already, may i suggest that you become a member of the
Zebrafish Husbandry Association. This is a world wide group dedicated
to the promotion of better understanding the needs of zebrafish, and
larval rearing just happens to be the flavour of the month at the
moment. The ZHA recently organised a webinar presented by Isaac
Adatto on the "Evaluation of Various Live Feeds and Feeding Regimes on
Growth and Survival of Larval Zebrafish".
If you can spare the time, it would be something you would find most
interesting.
you can find the ZHA here:
http://www.zhaonline.org
then if you want to find the webinar, look for isaac's talk in the ZHA
Library.
Jason
chubbyjayu
Heartfelt thanks to all who replied to my post with hints.
Just an update, the fry are doing fine at 21 days post fertilization.
The mortality rate too, has dropped as now I introduce the fry to
macerated fish food at day 5 and by day 6 they seem to be eating it.
(Of course, paramecium is added for the smaller ones, and artemia is
given to the older fry)
Thanks once again!
Cheerio
Jayasree