Q: "Didn't you once say chocolate was ok to give in tiny amounts to
    ferrets? ...It is deady to dogs.  Why can't you use dogs as a "model"
    for ferrets eating chocolate if you can use them for eggwhites?"
 
A: Well, when I saw Elvis while driving through Roswell, he said to leave
   those hound dogs alone.
 
This is really a great question.  In short, the problem in dogs (and other
mammals) is they metabolize theobromide--the active alkaloid found in
chocolate products--slowly (unsweetened chocolate has 390-450 mg/oz, milk
chocolate has 44-60 mg/oz, white chocolate has negligible amounts).
Theobromide acts much like caffeine and works as is a general stimulant.
A lethal dose (kills 50% of a population) is about 250-500 mg per kilogram
of body weight, but can be as low as 115 mg/kg.  In dogs, the problem is
the half life of the theobromide; up to 18 hours (the half-life is the time
it takes for 50% of the compound to be eliminated or metabolized).  I know
of no published data (and I looked long and hard) regarding the half-life
of theobromide in the ferret or any other mustelid.  (All these values come
from the Merck Vet Manual.)
 
Lets look at this from two different perspectives; 1) dogs as a model for
theobromide poisoning in ferrets, and 2) the actual dangers to ferrets.
Theobromide is directly absorbed into the blood and circulates throughout
the body to do it's magic.  Compare this to avidin (the egg white
ingredient) which remains in the intestine until it is broken down by
enzymes or eliminated in the stool.  So, avidin is ONLY a problem when
consumed at the same time as biotin; once bound together, they are not
metabolized and are eliminated.  The physiological mechanisms are different
and the effects they produce are different.  The worst part of the
comparison is that dogs do not react to theobromide like most animals; they
react much worse.  Avidin, in contrast, acts independently of the animal
when it binds with biotin.  In other words, because of their unique
physiology, dogs are a poor model to show how theobromide works in other
species.
 
What about chocolate in ferrets?  A lot of people have come under attack
for using chocolate chips as the occasional treat for ferrets because of
the danger of theobromide poisoning.  Is it a problem?  Assume that the
Lethal Dose of theobromide is the same for all species and the dose is
400 milligrams per kilogram of body weight (this is a horrible assumption
because we already know dogs have a special problem with theobromide, and
we have no idea what the Lethal Dose is for ferrets, nor the half-life, but
lets do it for the illustrative purposes).  So, what is a lethal dose of
theobromide?  Well, it would be about 400 mg for a 1 kg (2.2 lb) ferret,
or about an ounce of bakers chocolate, 10 oz of milk chocolate, or an
unlimited amount of white chocolate.  Now, I've been told a cup of chips
is about 6 oz, so an oz of chips is about 1/6th of a cup.  Now, making all
the really bad assumptions already discussed, a 1 kg ferret would have to
immediately consume 1/6 cup of bakers chocolate chips or 1 2/3 cups of milk
chocolate chips before reaching the Lethal Dose.
 
Now, I can't tell you how many chocolate chips there are in a 1/6 of a cup,
but it must be about a handful.  So many, in fact, that a ferret's stomach
is too small to hold them all at one time.  As for milk chocolate, it is
inconceivable that a ferret could eat enough to kill itself, even if it was
as sensitive to theobromide as a dog (which it isn't).  Think about it.
A ferret would have to immediately eat more than half of a bag of milk
chocolate chips before it consumed enough theobromide to kill itself
(12 oz bag x 60 mg/oz = 720 mg theobromide).  In either case, bakers OR
milk chocolate, the amount of theobromide in a single chocolate chip
constitutes little danger to a ferret.
 
What is a safe dose of raw egg white for a ferret?  It has been established
4-6 raw eggs a day will cause biotin deficiency in a body builder.
Assuming 5 eggs in a 150 lb person is bad, a single egg per 30 lb. is bad.
That means if a 2 lb ferret eats about 1/15th of the white in a raw egg on
a daily basis, it could develop a biotin deficiency.  So, either cook the
egg OR serve it only a few times a week.  Problem solved.
 
Bob C and 16 Mo' Chocolate Egg Eaters
[Posted in FML issue 3027]