[RML] Pseudomugil diet
Mach T. Fukada (fukada at hawaii.edu)
Mon, 14 Sep 1998 11:49:57
Got some prelminary data for a feed trial I am working on with the people
at the U. I have been supplying them P. furcatus for their work and we
have been finding out several things. I will post a adobe acrobat file of
the latest Honolulu Aquarium Society newsletter with a breif rundown on
what was being done. They were using a high fat diet and got them to grow
really rapidly. Also color additives were tested, spirulina and
anthoaxthin (sp?) were found to produce really significantly brighter
yellow/oranges,and reds. (even females displayed more color,even onthe
pectorals, dorsals, etc) However, I noticed that a fair number of fish had
spinal deformaties. I sent some fish off to a fish Vet (to check for
mycobacteriosis) and he found that there were fatty deposits in the fishes
liver (indicating possible impairment, but not mycobacteriosis). The
deformaties we councluded seemed to be cosistant with deffiencies of Vit C,
Vit D, Ca or some other mineral. I have theorized that the impaired livers
might have prevented the normal Vit D metabolisms resulting in the bent
back deformaties associated with mycobacteriosis (which is also a result of
liver impairment). Also the growth rate of the fish might have been so
great that the Ca or Vit C requirments may have also increased. We are
going to redo the trials and increas Ca.
I am going to try color enhancement via spirulina and the other stuff and
see if the deformaties appear. If they do I will have the livers of these
fish checked out for impairments, lesions, etc. I do suspect that in
nature the zooplankton that the fish feed on naturally concentrate algae
components, compunds, pigments (beta carotene, Anthothaxin ? sp) and these
pigments are lacking in artificially reared fish. I am going to do some
tests on my own and get back to the group. I have noticed that the juiced
fish haven't been fed any more of the stuff but still retain color. Also
adult fish reared without these additives do not seem to develop the same
amount of color. Is it possible that the chromatophores are made at a
certain point in the fishes development? Also based on the color deposition
in certain areas associated with secondary sexual characteristics is it
possible that the compounds in these additives have hormone analog properties.
Right now I suspect that: the high fat diet although causes rapid growth,
may impair liver functions resulting in deformaties. It also may reduce
the longivity and fecundity of the fish.
Spirulina and anthothaxin may be important pigment precursors.
I think we are making some headway into the dietary needs of bows so Iwill
keep onto it. I am going to try and suggest other fish to these people.
Maybe P. cyanodorsails (if I can get them big enough and into freshwater, I
have found that if they are kept in a high ph hard water situation they
seem to be thriving , another experiment for another time) maybe P.
tennelus, and P. signifer. Might be a good thing to try it on M. bosmani
and see if the yellow orange half is enhanced in the same way (Gary you
think I could get some bosmani fingerlings from you? ;-)
Mach T. Fukada, Web Master
fukada at hawaii.edu
Honolulu Aquarium Society
http://www.geocities.com/Heartland/Meadows/2948/HASF.html