I don't have the exact time-line for ferrets but I do have information
for dogs.  Remember that ferrets have faster metabolism action than dogs
so the time-line would need to be adjusted.
 
When food is deprived, biochemical functions changes occur.  In the dog,
this process begins within twenty-four hours.  The highest priority of
the metabolic processes is to keep the blood glucose concentration at a
normal level.  If the blood glucose (blood sugar) level drops too low
for any reason, the brain, heart, muscles and kidney function shuts down
rapidly and death comes quickly.  When the animal has no opportunity to
eat, in ferrets this would mean no opportunity to eat the food they are
perceive as food or are familiar with, the body will take stored glucose
from the liver first, then from muscle reserves, This is done by changing
the biochemical processes to different chemical pathways that make
glucose readily available.
 
After about two days the liver reserves of glycogen (glucose) will be
depleted in the dog.  In order to keep the blood level of glucose in the
normal range, new chemical pathways open, called gluconeogenesis, where
the liver and kidneys create molecules from complicated biochemical
reactions so that fats and proteins are extracted from adipose tissue
and muscle.  As the glucose reserves are tapped and diminished, chemical
reactions kick in to create glucose internally from those protein and
fat reserves.  Energy to run the bodys machinery (muscle, brain, kidney,
heart and other organ functions require energy to fuel their activities)
is now fueled less by glucose and more by fatty acid extracted from fat
reserves.
 
On the third day of food deprivation the metabolism (metabolism refers
to all the chemical reactions going on to maintain life) slows down.
(This occurs in people when not enough calories are consumed as in
dieting and not consuming what the body needs - our metabolism slows
down.)  This lower, or slowed metabolic rate continues as long as no food
is consumed.  The lowered metabolism is a survival mechanism to decrease
the utilization of body fat and muscle for energy.  Lowered blood sugar
levels changes insulin secretion by the pancreas (with ferrets being
prone to insulinoma, this is hazardous) which in turn lowers thyroid
hormone levels; and it's the thyroid gland function that ultimately
dictates the metabolic rate.
 
During starvation the liver releases chemicals called ketones into the
blood stream; ketones are then used as a source of energy for the body
cells.  By creating ketones and fatty acids to be used as energy
sources, the body conserves what little glucose is circulating so that
glucose-dependent red blood cells and important kidney tissues can
continue to access glucose.  Red blood cells and kidney tubule cells
cannot utilize anything other than glucose for cell energy needs.
Personally, I could never let a ferret go 24 hours without eating.  I
care for old and ailing ferrets and many times it is a syringe of recipe
every hour or so when they are not eating on their own.  When they have
surgeries I feed them at 4am and feel terribly guilty when I can't allow
them to eat with the group at 6am.  Ferrets depend on us for everything.
 
Personally, I have and always will recommend slow food changes, whether
it is kibble or what is referred to as natural.  Ferrets arent like
dogs.  They wont necessarily eat whatever is available when they are
hungry.  Ive seen the deadly results of the is misconception.  I have
heartbreaking times in trying to find a food that a new kid will eat
when I have no idea of what they did eat.  Because ferrets are sensory
animals, they imprint on the foods they have been fed and do not
recognize other types of foods as food.  This is why I serve 20+ kibble
choices.
 
Warm hugs to all. tle
[Posted in FML issue 5206]