Mr. XXXXXX has asked several excellent questions regarding the ferret's
digestive anatomy and conversely how it effects the ferret's diet.
Scientifically, a diet is that amount of nutrients in the proper quantity,
quality and balance, feed to an animal in a palatable form, so that in
a twenty-four hour period it will maintain or support its physiological
state. Because ferrets have such a unique digestive system they are
strictly limited as to what they can eat. As has been stated in many
references, ferrets are obligate carnivores, meaning they must have a meat
based diet daily. This is not a preference in selecting a food it is a
must if the ferret is to live. Selecting a diet first and foremost must be
on the basis of meat content. Many volumes have been written by numerous
authors as well as myself in great detail on this subject. I will not
cover selecting and evaluating a diet here.
Regarding MR. XXXXXX's questions on the effect of the ferret's metabolic
anatomy relative to what and how a ferret eats.
A ferret has no ceacum. Dogs, cats, humans and most other animals have a
ceacum. In those animal, the ceacums is located at the point where the
small intestines widen to become the large intestines. This location is
called the ileocolic junction. The ceacum itself is a blind pouch which
functions to provide some digestion of the complex carbohydrates, and
fiber. It contains nonpathogenic, symbiotic bacteria which secrete enzymes
in the ceacum, which in turn digest the fiber and complex carbohydrates.
The rabbit and horse have a disproportionate sized ceacum relative to their
body size and most other animals, which allows them to eat large quantities
of fibrous feedstuff such as hay and grass. Neither of these animals nor
any other mammals secrete fiber digesting enzymes, these are only secreted
by the bacteria in the ceacum. On the other hand, ruminants, such as
cattle, sheep, goats, deer, etc., have a specialized digestive system,
which allows them to digest high fiber diets such as grass and hay even
more efficiently than the rabbit or horse. This is because the have a
large paunch called a rumen which host to billions of symbiotic bacteria
and single cell microorganism which in turn secrete fiber digesting enzymes
that then break down the fiber in the food. Back to the ferret. The lack
of a ceacum limits the ferret in eating fiber containing foods. From our
research we found that fiber should not exceed 1.5% to optimize the
digestibility of the whole diet. This is another reason why I recommend
not feeding cat food or any other foods as the primary diet for the ferret
if it contains more than 2% fiber.
The second anatomical difference between ferrets and other carnivores,
is the short large intestine or colon. Ferrets do have colons but an
extremely short one. It is approximately 10 cm (3.94 inches) long. This
proportionally is about 1/3 to 1/2 as long as a cats colon. The ferret's
colon contains very little convolutions or folds which would aid in the
water and nutrient recovery from digestion. The surface is almost smooth.
There are very few bacteria in this area which is also contrary to most
other animals which means the ferret cannot synthesize any B vitamins.
These two anatomical differences plays a major role in what the ferret
eats. The rate of passage for food from the time the ferret eats till
it poops is about 3 to 4 hours. This further dictates that high quality
animal protein must be the major portion of the diet. Probioticts or
Prebiotics such as yogurt, lactobacillus, etc., or yucca, fructo-
oligosaccharides (FOS) are therefore non effective in the healthy ferret
because the intestinal track does not support bacterial growth as does
those of other animals. This is a major reason why holistic foods are a
rip-off and have no physiological benefits in ferrets.
The ferret has a very specialized gut which has evolved eating meat as its
primary protein and energy source. As Bob Church pointed out, the wild
ancestors of the ferret, the polecat, also ate insects, eggs, and many
types of small prey. There digestive system secrets very powerful
proteolytic and lipolytic (protein and fat digesting) enzymes. They also
secrete some lipase enzymes in the small intestine which digest the
simple carbohydrates and sugars. However, their digestive system can be
overwhelmed with simple carbohydrates such as sugar, dextrose, and fructose
(fruit sugars) if feed foods or treats containing them. Fruits such as
grapes, raisins, bananas, apples, cantaloupe contain both high levels of
sugar as well as fiber. This is a double whammy for a ferret and should
not be fed. A good ferret diet should contain at least 34 to 37% protein,
18 to 24% fat no more than 1.5% fiber and no more than 25% carbohydrates
and no sugar. Of course the major protein sources should be from high
quality chicken byproducts, meat, eggs and liver. Diets with gluten, soy
or other complex vegetable proteins cannot be digested by the ferret and
can even cause digestive problems. Regarding the effects of highly soluble
carbohydrates such as sugar, or high carbohydrate diets (35% or higher), I
am not aware of any studies which have established the long term effect of
their feeding. Knowing their anatomy and reviewing the data from our own
research, I do not believe it would be in their best interest for the long
term health considerations of the ferret.
Sincerely,
DR Tom Willard
[Posted in FML issue 3406]
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