[Zbrafish] Chordal structure Malformation

françois via zbrafish%40net.bio.net (by busquet.francois At gmail.com)
Tue Nov 21 07:51:51 EST 2006


Dear all,
since one week, a third of my fish embryos incubated in fish medium at
26°C,  developed chordal structure malformation like a ,,zigzag"
after 24hpf. I didn't know from which aquarium it comes from because
I collected all the eggs from the boxes in one big petri dishe.
Therefore, I first checked in which aquarium this could come from. I
collected once again fish eggs depending on the aquarium origin and I
incubated the fish eggs in fish medium at 26°C.

Today, I figured out that more than 80% fish embryos displayed again
chordal structure malformation for every aquarium. Moreover, I changed
all the population for one aquarium last weekend and replaced by
younger ones (around 8 months) but in the same water. It didn't make
any differences, the chordal malformation was also for 80% of fish eggs
for this aquarium.

We use a static system where fish medium is totally replaced every 15
days. The fish medium is based on deionized water + CaCl2 + MgSO4
(with Ca:Mg ions is 4:1) + NaHCO3 + KCl (with Na:K ions is 10:1). I
heard that chordal structure malformations could be linked to heavy
metals presence or from some infectious diseases or even vitamin
deficensies.
Any comment are very welcome!
regards
françois busquet
PhD student/ Ecotoxicological Institute/ Merck KgaA/ Germany.




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