While awaiting the return of the next series of Ad Libitum posts from =
one of my reviewers (he had a death in the family), I'll take a moment =
to answer a few questions the ad libitum series has generated.
 
Q: "Is it carbohydrates that are bad for ferrets, or kibble?"
 
A: That is sort of like asking if the fall is bad, or the sudden stop.
 
It is not that digestible carbohydrates are bad per se; it is that TOO
MANY of them are bad.  The problem is defining what are "too many."  To
answer that question, I take a holistic approach, looking at the life
history of the animal, comparing changes caused by domestication to what
is found in nature.  A close look at ferrets indicates virtually NO
changes have taken place in the digestive physiology of ferrets in the
last 2500 years.
 
The milk-and-bread diet never became popular with ferreters until AFTER
both milk and bread became cheaper to feed to ferrets than meat.  The
first reliable source I have been able to find detailing the milk and
bread diet was published in 1770, in line with the rise of agricultural
surpluses.  The kibbled diet evolved directly from animal
experimentation: scientists needed a food that can be dumped in a cage,
and would keep the animal alive until they were sacrificed.  Both diets,
although around for a couple of hundred years, are too recent to have
spurred significant physiological changes in ferret digestion (the same
is true for dogs and cats, domesticated far longer).  It is thus a safe
assumption to consider the ferret and polecat to possess essentially
synonymous digestive physiologies.
 
Polecats have NO dietary requirement for carbohydrates, and neither
do ferrets.  Both have essentially identical abilities to completely
synthesize their energy needs from protein, which is quite a trick in
terrestrial mammalian circles.  The reason they can do this is because
they had to--they evolved consuming a diet made of protein (and 15-20%
fat), with less than 5% carbohydrates (mostly animal "starch", not
significant amounts of plant starches).  They are not only adapted to
a fleshy diet from their teeth to their anus, but they are superbly
dedicated to such a diet.
 
Kibble is a dry feed where nutrients are held suspended in a gelatinized
starchy matrix.  The percentages of nutrients listed on the side of the
package are a very poor indice of quality because the extrusion process
can significantly change nutrient availablity and quality.  The problem
is the starch: the extrusion process generally makes them more
digestible, meaning the ferret, an animal superbly adapted to
manufacturing energy from protein, now has an "energy glut." Research
involving dozens of species, done over scores of years, indicates energy
overnutrition is tied to decreased life spans, increased cancers,
autoimmunity problems, and exacerbated effects of disease.  Is that bad?
I think so.
 
Bob C
[Posted in FML issue 3972]