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[Killietalk] Re:HUFAs
>From my reading on the subject (and most of the work has been done on marine
fishes), the need for and the functions of HUFAs should be the same in all
fishes and vertebrates in general, since fishes (and people) cannot
synthesize these substances. They are essential to neural system development
and for certain hormonal substances. That HUFA enrichment has made such an
important difference in marine fish propagation is in part because there are
so few nutritional sources for propagation of marine fry, while we have many
alternatives to enriched rotifers for freshwater fish fry. The newer
freshwater feeds contain HUFA sources. We use insects (fruit flies) and some
other inverts rich in HUFAs precisely because of their HUFAs. Insect fats
(rich in HUFAs) play the same role in freshwater fish development that
copepod fats play in marine fish development. There is an indirect
osmoregulatory role for HUFAs, but with regard to hormone synthesis rather
than a direct role in ion transport. Our freshwater fishes get some HUFAs
from brine shrimp (not much), and from good flake foods, raw shrimp, fruit
flies, and probably some common crustaceans. However, we should expect
increased growth and survival rates if we add HUFAs to brine shrimp or other
foods (like microworms). I haven't tested this (now here's a grad student
project), but I would expect that HUFAs fed to spawning adults might
increase the storage of HUFAs in fish eggs, and help reduce bellysliders,
deformities, and early mortality that MIGHT be related to a deficiency in
these essential nutrients.
----- Original Message -----
From: "Barry Cooper" <bjc3 at centurytel_net>
To: "killifish discussion list" <killietalk at aka_org>
Sent: Thursday, June 10, 2004 7:33 PM
Subject: Re: [Killietalk] hybrid vigour
> Bob, that is only true on marine fish isn't it? My understanding is that
> the big breakthrough in raising marine fry came when it was realized that
> they had an absolute requirement for HUFAs. Freshwater fish don't seem to
> have the same requirement. I would not argue that supplementation with
> HUFAs is of no value, but for freshwater fish it is not a requirement.
>
> Barry
>
> At 02:54 PM 6/10/2004 -0400, you wrote:
> >Yes. HUFAs are Highly Unsaturated Fatty Acids. Certain types (called
omega-3
> >and omega-6) of these fatty acids are needed in the diet (just like
> >vitamins), because fish cannot synthesize HUFAs from normal diet intake,
and
> >they are important for nerve development and function, and for other
> >purposes.
> >
> >----- Original Message -----
> >From: "Jim Clark" <jim_clark.b at bayer.com>
> >To: "killifish discussion list" <killietalk at aka_org>
> >Sent: Thursday, June 10, 2004 2:49 PM
> >Subject: Re: [Killietalk] hybrid vigour
> >
> >
> > >
> > >
> > >
> > >
> > > What are HUFA's? Some kind of Fatty Acid
> > >
> > >
> > >
> > > "Robert Goldstein"
> > > <rgoldstein at rjgacarolina_com> To:
> >"killifish discussion list" <killietalk at aka_org>
> > > Sent by: cc:
> > > killietalk-bounces+jim.clark.b=bayer.
> >Subject: Re: [Killietalk] hybrid vigour
> > > com at aka_org
> > >
> > >
> > > 06/10/2004 10:58 AM
> > > Please respond to killifish
> >
> > > discussion list
> > >
> > >
> > >
> > >
> > >
> > >
> > > Tony reminded me of another recent publication relevant to fish
health.
> >Many
> > > of you are familiar with light shock, the sudden exposure to bright
light
> >of
> > > fish that have been in boxes for a few days. These fish (usually
discus
> >or
> > > angels, but I've seen this in young banggai cardinals and in clownfish
fry
> > > too) go into tetanus, getting rigid, trembling, their gill plates
> >extended.
> > > They fall to the bottom and rarely recover. I've never thought of this
in
> > > terms of anything but an effect of light causing stress-induced
mortality.
> > > However, a recent publication showed that fishes fed a diet rich in
HUFAs
> > > were resistant to light shock. So we see that diet can play an
important
> > > role in how a fish responds to a physical stressor.
> > >
> > > ----- Original Message -----
> > > From: "Tony Terceira" <terceira at ride_ri.net>
> > > To: "killifish discussion list" <killietalk at aka_org>
> > > Sent: Thursday, June 10, 2004 1:42 PM
> > > Subject: RE: [Killietalk] hybrid vigour
> > >
> > >
> > > > At 11:17 AM 6/10/2004 -0600, you wrote:
> > > > >Gary Elson wrote:
> > > > >
> > > > > >
> > > > > > can anyone point me to online resources or personal observations
> > > > > > on hybrid
> > > > > > vigour in population crosses in killies? I'm specifically
curious
> > > > > > about the
> > > > > > effect such crosses have had on fry growth rates.
> > > > > >
> > > > Hi . I think the LAST thing we need to do is play with
> > > > hybrids. We have worked for over 40 years, keeping populations
isolated
> > > > and not inter breeding them. We have an entire publication devoted
to
> > > > specific collection codes and sites where specific killies were
> > > > collected....................... I can find no reason other than
> > > scientific
> > > > to play with hybridization.
> > > >
> > > > Killies are generally very vigors on their own.............
> >some
> > > > of the annuals have been in the hobby for over 80 years and they are
> >doing
> > > > fine as far as color and growth are concerned.
> > > >
> > > >
> > > > We do not know enough about the concept of species to play with
> >population
> > > > hybridization........ I can tell you from early hybridization I did
with
> > > > the bivittatum species group. that results are totally
> > > > unpredictable.......... Sterile at F1, fertile at F1 then sterile at
F2
> > > > etc........ ..
> > > >
> > > > Feed you killies a varied diet with as much live food as
> > > possible,
> > > > change water frequently and they will continue to be quite vigors
for
> >many
> > > > years to come................
> > > >
> > > > Tony
> > > > Tony Terceira
> > > > Scituate, Rhode Island
> > > >
> > > > Visit our Web Site
> > > > www.thefishwizards.com
> > > >
> > > >
> > > > To join the AKA see http://www.aka.org/pages/join.html
> > > > Archives are at http://fins.actwin.com/killietalk/
> > > >
> > > >
> > >
> > >
> > >
> > > To join the AKA see http://www.aka.org/pages/join.html
> > > Archives are at http://fins.actwin.com/killietalk/
> > >
> > >
> > >
> > >
> > > To join the AKA see http://www.aka.org/pages/join.html
> > > Archives are at http://fins.actwin.com/killietalk/
> > >
> >
> >
> >
> >To join the AKA see http://www.aka.org/pages/join.html
> >Archives are at http://fins.actwin.com/killietalk/
>
>
> To join the AKA see http://www.aka.org/pages/join.html
> Archives are at http://fins.actwin.com/killietalk/
>
To join the AKA see http://www.aka.org/pages/join.html
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