We have read of, but not encountered one other group having trouble with
very high protein; some ferrets with insulinoma defy the usual routine
for early stages and do better with more carbs, and for some also having
dietary sugars always available -- which used to be a standard part of
the treatment routine about a decade or more ago.  In end stage
insulinoma it is not unusual to get extra quality time by providing
sweets, but in early insulinoma the current hypothesis is that there will
be less blood glucose bouncing by keeping protein high and minimizing
carbs and sugars.  Not all vets agree on that hypothesis about this
pattern of feeding in early stages because islet cell tumors do not
respond to blood glucose levels; they just always turn out high levels
of insulin, and because the meds used work primarily by increasing blood
glucose levels.  Reducing carbs and sugars in those with early insulinoma
does seem help a good number of ferrets, though, just as adding them back
in during the end stages does.
 
Anyway, I just think that general condemnations of foods read in posts
are often made prematurely, sometimes based upon hypotheses but most
often based upon limited personal experiences, and sometimes those people
need to be more careful to point out what is a hypothesis when discussing
those so that those with exceptions or with ferrets who don't respond as
expected will not be confused or hurt, but most posters need to think
more about avoiding strong words based upon limited experience.  Some
foods are garbage, plain and simple.  I realize that.  Others work just
fine for having low disease levels and decent life spans.  Yes,
exceptions are important to know about, but one or two ferrets does not a
full population make though they do point out the importance of suiting
the diet to the individual, so know that exceptions exist but also know
what they really mean: that nothing is perfect for every ferret.  A diet
on which many will thrive may upset the GI tract of a ferret who has IBD,
and another diet on which many with thrive will cause cystine stones in
one who may be prone to those.  What is too much in the way of
carbohydrates or sweets for one may be needed at a different time for
medical reasons.  It's the same as with people.  There are a few general
rules.  In ferrets they are obligate carnivores; it's a general rule.
In humans we s a population thrive best with large percentages of
veggies, fruits and whole grains in our diets; it's a general rule.
Here's one more general rule: diet is not one size fits all so realize
that exceptions exist and accept them as such.  So, not all people do
best on what generally suits the population best, and not all ferrets do
best on what generally suits the population best.  Honor exceptions, but
realize that until one can tell exceptions from the general population
it is best to not make sweeping statements without qualifying them and
avoiding emotionally loaded wording.
 
(BTW, from my personal experience and going from reading so very many
posts through the years is that the ferrets available in the U.S. seemed
to be stronger in past decades back before there were so many with
assorted "fancy" genetics -- part of which should be no surprise since
the neural crest genetics from Kit is a documented oncogene across
mammalia and oncogenes can increase the likelihood of malignancies,
before there were so many ferrets bred outside the natural breeding
season, and before there were so many night lights and equipment lights.)
[Posted in FML issue 4654]