Re: Skewed sex ratios and Androgens (STOP USING ACRIFLAVIN!)

["killiman" <killiman at iquest_net>]

Use no medications. Keep the eggs out of the light, remove dead ones as soon
as spotted.(daily).
Time to go build another worm bed as the water changes automatically.

killiman at iquest_net
Al Anderson
317 253 2170
----- Original Message -----
From: "Chris Browning" <fisher25000 at yahoo_com>
To: <killietalk at aka_org>
Sent: Wednesday, December 18, 2002 7:05 PM
Subject: Re: Skewed sex ratios and Androgens (STOP USING ACRIFLAVIN!)


> Ahah!!! An answer as to why ALL eggs I hatch are
> males!!! Thanks David!
>
> Anyone out there have a suggestion as to what to use
> instead?
>
>
> --- David Lains <david at zfin_org> wrote:
> > Hello All
> >
> > While searching for info about chemically changing
> > the sex in zebrafish I
> > came across this: Applied Fish Pharmacology by K.M.
> > Treves-Brown, 2000
> > Kluwer Academic Publishers. On page 244 chapter 18:
> > Sex Control section B:
> > Androgens. Verbatim:
> >
> > b) Androgens:
> > The androgen usually used is methyl testosterone
> > (MT).  It is practically
> > insoluble in water but is soluble in alcohols.  It
> > is obtainable as a powder
> > and for immersion use it may be formulated in the
> > same way and at the same
> > concentration as oestradiol, but the usual
> > concentration in the diet is
> > 3mg/kg and hence the initial concentration in
> > iso-propanol should be 3mg in
> > 200ml.
> > A large number of synthetic and natural oestrogens
> > and, more particularly,
> > androgens and have been tested for this use.  One
> > such androgen,
> > 11-Beta-hydroxy-androstenedione (OHA), has the
> > advantage claimed for it that
> > it is a natural hormone, but it has been found
> > generally inferior to MT and
> > has not so far been adopted commercially.  As a
> > general rule the synthetic
> > androgens have proved both cheaper and more slowly
> > eliminated.  Among the
> > later, 12-Alpha-ethinyl-testosterone and mibolerone
> > are notable.
> > (NOW IT GETS REALLY INTERESTING!)
> > Some non-steroidal compounds have sex controlling
> > effects on fish.
> > ACRIFLAVINE, which is a mixture of ACRIFALAVIN and
> > proflavin, will
> > masculinize adult mosquito fish and has an
> > androgenic action on tilapia at
> > doses equimolar with MT.  Tamoxifen, which is an
> > anti-oestrogen rather than
> > an androgen, is also active in tilapia.
> > end of section.
> >
> > Now it sounds like there's an interesting experiment
> > that could be done here
> > if someone has the time.  All I know is I'm glad I
> > don't use Acriflavin and
> > my DAG MON throw an equal sex ratio!
> >
> > Best Fishes
> > David
> >
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>
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