Mr. Lipinski brings up an interesting point about feeding yogurt to
ferrets.  His argument however, is based on his understanding or
misunderstanding of human and ferret digestive physiology.  Christopher,
a student in the human holistic medicine and a respondent to this same
email, also is incorrect on the cause of the benefits of yogurt in ferrets
relative to humans.
 
Physiologically, ferrets, which are obligate carnivores, are quite
different from humans, especially in the digestive system.  The muscle
structure of the esophagus, the proportional size of the stomach, the small
intestine and the colon are all quite different between the two species.
The intercellular layers of the small and large intestines of humans and
ferrets are entirely different.  These differences along with the level
and types of enzymes secretions, etc., make comparing the two species
impossible when it comes to determining nutrient digestibility from food
stuffs.
 
The functional benefit of yogart as well as other types of probioticts or
prebioticts lays in the fact that the "good" bacteria or non pathogenic
bacteria overgrows the "bad" bacteria and makes for "better" or more
complete digestion.  This function takes place in the ceacum and colon of
the humans not in the stomach or small intestines.  The ferret lacks a
ceacum, an ileocolic valve and an effective absorptive colon.  Further,
the ferret's colon contains little bacteria and is practically sterile.
This is the main reason that pre and pro bioticts or yogurt can have little
to no effect in ferrets as it does in other mammals.  The human as well as
other animal such as dogs, but not cats who are also obligate carnivores,
can benefit from yogurt, acidopholis inoculants, pre and pro bioticts.
 
The other fact that must be considered is the presence of lactose in the
yogurt which can cause a looseness in stools because adult ferrets not on a
diet of milk products lack lactase in sufficient quantities to digest the
lactose in the yogurt.  Mr. Lipinski's ferret has been on yogurt for years,
as he states, and therefore has maintained adequate levels of lactase so
it is able to digest the lactose rather efficiently.  The protein in the
yogurt is casein and is a very high quality as well as is the fat.  Since
lactase is an induced enzyme, ferrets, cats and dogs can adapt to milk
products given enough time, usually 6 to 12 weeks.
 
Mr Lipinski does bring up a cogent point in identifying the digestive
benefit of increased surface area of food stuffs.  This along with the
nutrient quality mentioned above is the source of the benefit of yogurt
to ferrets and not the bacteria replacement in the gut.
 
DR Thomas Willard
 
[Sukie's note:  Tom Willard's PhD is in veterinary nutrition.]
[Posted in FML issue 3397]