From:
Marie Bartholdsson
Date: 2001-11-10 14:07:00 UTC
Subject: avidin and thiaminase
I did some research on avidin and thiaminase:
Raw egg white contains avidin. Avidin has a strong biological interaction
with biotin (vitamin H). One molecule of avidin is binding four molecules of
biotin. Feeding raw egg white in larger amounts over a period of weeks may
cause biotin defiency.
Thiaminases are enzymes found in various amounts in raw fish/shellfish and
also in some plants and bacterias. When ingested these enzymes split thiamin
(vitamin B1), and can thereby cause thiamin deficiency.
As with the avidin in raw egg white, you will have to feed larger amounts of
raw fish, rich in thiaminase, over a period of weeks before negative effects
are noticed.
Both avidin and thiaminases are denatured by heat, and cooking the raw egg
white or the raw fish (200o F for 15 minutes) will render the
avidin/thiaminases inactive.
So you can safely feed cooked egg white and fish, and it is also safe to
feed eggs and fish raw, if only done occaisonally and in smaller amounts.
Examples of fish containing thiaminase are:
smelt, caplin, herring, sprat, garfish, id, different types of carp,
different types of bream, roach, tench, rudd, vimba
Marie
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