10. Ferrets need to have food constantly available.
 
FALSE.  For several years, I have tried to track down the origin of this
myth, but have been unsuccessful in those efforts.  I do know it was not
initially based on a scientific study or recommendation.  I don't think
it started out as "ferrets need access to food at all times," but rather
evolved out of a misunderstanding of ferret metabolic needs, perhaps
combined with the observation that ferrets eating kibble will often eat
many small meals.  Whatever reason, the idea that ferrets need to have
food constantly available is patently false.  Neither New Zealand feral
ferrets, nor European polecats, nor ferrets kept for close to 2500 years
had food constantly available; why are our ferrets somehow different?
In fact, a tremendous amount of data suggests the practice, called 'ad
libitum feeding' (or ad lib; feeding without restraint), leads to obesity
and associated diseases.
 
I think the idea is a result of the kibble diet.  Highly refined and
processed starches in kibble are converted into disaccharide sugars
during digestion, and ultimately converted into glucose, or blood
sugar.  Elevated blood sugar spurs the pancreas into increasing insulin
production, while decreasing the production of glucagon.  Glucagon
stimulates cells and organs to mobilize and liberate energy stores, and
to increase ATP metabolism.  Insulin does the opposite.  When a ferret
eats a meal heavy in starchy carbohydrates, the subsequent tremendous
increase in blood sugar simulates a corresponding increase in insulin,
moving glucose from the serum into the cells of the body.  Once absorbed,
glucose is converted into glycogen in muscle tissues and the liver.
Glycogen is excess of needs is converted by the liver into fatty
acids and stored as fat within the liver, as well as various deposits
throughout the body.  As blood sugar drops, it is detected by the
pancreas, and glucagon is released, causing glycogen to be released.
Increased blood insulin levels also initiates a cascade of events that
initiates a feeling of satiety, while glucagon starts a cascade leading
to feeling of hunger.  So, when a ferret eats kibble, the rise in blood
sugar shuts down the hunger response and the ferret walks away, satiated
(but perhaps not having met metabolic or nutritional needs).  As the
blood sugar drops, the hunger response is stimulated, and the ferret
returns to the dish in a relatively short period of time.
 
In contrast, a ferret that eats meat doesn't have the rapid rise in
blood sugar, because they are not consuming significant amounts of
carbohydrate.  In these ferrets, glucogenesis takes place in the liver
at a much slower rate, so they feel hungry longer, and eat more (some
carnivores seem to be hungry ALL the time).  Because blood sugar drops
slowly after feeding, these ferrets take a longer time to return to the
food dish.  When someone says, "Ferrets eat to met energy needs," they
are talking about this basic mechanism.
 
What this means is the tendency for ferrets to eat frequently is actually
caused by the food the ferret is eating.  Here's the rub: when the
kibble-eating ferret returns to the food dish, they are still far in the
plus-column, energetically.  That is, they have been spurred to eat
because of a drop in blood sugar, but they still have considerable stores
of energy stored as glycogen and fats.  Over time, these ferrets become
obese, resulting in lowered activity levels that lower muscle tone.
Their meat-eating counterparts remain solid and muscular, and are far
more active.
 
The number of times a ferret has to eat is DIRECTLY related to the
nutritional quality of the diet, concentration of nutrients, and stomach
expandability.  High quality, nutrient-concentrated diets (animal
carcasses) require fewer feedings per unit of time compared to low
quality, nutrient-diluted diets (kibble), assuming stomach expandability
is the same.  Even so, the number of times a ferret on a kibble diet is
metabolically required to return to the food dish is never as many
times as they actually do.  Because of hunger spurred by blood sugar
fluctuations, ferrets actually eat more then needed to meet metabolic
needs.  It all boils down to starch-impacted blood sugar levels.  The
reason so many people remark on the muscular build of ferrets in Europe
is because most of those animals eat a meat-based diet rather than kibble
every day, for every meal.  It is NOT genetics -- it is diet, pure and
simple!  (Caging is also a factor, but if activity levels are equalized,
a kibble diet STILL results in fat ferrets!).
 
A number of people will argue an ad libitum diet is better for ferrets,
referring to this argument as a "hypothesis" and shouting that no studies
have been performed in ferrets.  Such an argument is BEYOND obtuse and
shows the person not only has a lack of understanding of basic energy
metabolism, but they are incapable of performing basic calorie
calculations (calories in ... calories used =  calories deposited as
fat).  While an ad libitum diet MAY be indicated in some extremely ill
or compromised ferrets, such a diet in healthy ferrets is a trip on
the Obesity train, destination Early Death.  In EVERY study of diets
in carnivores (regardless of species), an ad libitum diet resulted
in animals dying younger due to obesity-related ailments, including
cardiovascular, kidney, liver, and pancreatic disease.  Ferrets respond
to obesity exactly like humans do: with increased inactivity, frequent
blood sugar fluctuations, marked muscle flaccidity, amplified deposition
of excess body fat, deterioration of weight-bearing joints, and
over-taxing various organ systems.
 
Folks, this isn't a hypothesis, it is a fact, even if a study specific to
ferrets has yet to be published.  Radiation kills gnats, heat kills rats,
cyanide kills cats, starvation kills bats; you don't have to do a study
on ferrets to know the effects will be the same.  There have been so many
studies of the effects of an ad lib diet on mammals, including humans,
rats, dogs, cats, primates, wild canines, otters, and dozens more, that
the results can be considered a generalized rule of physiology (this
is the trick of veterinary care; mammalian physiology is so similar,
veterinarians only need to learn the exceptions).  About the only mammals
that seem to be exempt from the rule are wild herbivores, who eat such a
low nutrient diet that they need to constantly eat to meet nutrient
needs.  The bottom line is, not only is an ad lib diet NOT required for
ferrets, but such a diet is actually detrimental to their health.
 
Bob C
[Posted in FML issue 3942]