Cathy carried Dr. Ruth's post to the FML.
As Dr. Ruth pointed out, peas are in question as a food item for
ferrets, but they are not alone.
The separate FHL archives are down so I am including this past post of
mine that I sent after hearing from someone in Britain who mentioned
that she is in a relevant field of academics and work. She said that
with enough sulphur also present in the food the body can more easily
convert methionine into cystine instead of just leaving it as
Subject: I learned a mechanism today for peas playing a direct role in
cystine uroliths (cystine stones)
Date: February 14, 2013
To: FHL list, FML List
A kind researcher in bio sciences taught me today that foods that are
high in sulfur, which she says include peas and sweet potatoes,
facilitate the body biosynthesizing cysteine. So, beyond pea flour
being a useful binder for some of the foods that have very accessible
amino acids, and beyond some of those foods having added methionine
the peas may be a direct player in the production of cystine uroliths
She gave this site for seeing methionine content and peas are high
though not the highest:
The body can convert methionine into Cysteine; providing more of what
facilitates that conversion is a problem.
In that list I see at least one other food item found more and more in
So, when evaluating a food option it may pay to see if the food
contains ingredients which are high in sulphur (sulfur also an
acceptable spelling with one being more American and the other more
British) AND ones high in the amino acid, methionine. They do NOT have
to be the same ingredient. Two or more ingredients eaten about the same
time would be bad, too, if this mechanism is what is happening.
It is NOT known how many ferrets have the genetic susceptibility to
forming cystine uroliths, though reports of such stones in ferrets
increased greatly after high protein foods came out. That is because
the urinary system in such individuals allows cystine to precipitate
out of the urine if the diet is high in any of four amino acids, the
so-called COLA group which stands for Cystine, Ornithine, Lysine, and
Arginine. A diet too high in ANY of those amino acids can pose problems
for such individuals, so when the susceptible ferrets get too much
protein they can wind up in trouble.
Add onto that consideration that that body can create amino acids from
each other if the right things are available in high enough amounts and
you get to why peas apparently pose a risk factor for these genetically
A few ferrets who get cystine uroliths (urinary stones) have to have
medications that increase the pH of urine, but many thrive just by
living on a diet that is kept to no more than 35% protein. We have had
two who went on after their surgeries as one year olds for cystine
uroliths to live full lives for 6 more years in one case and 7 more for
the other if I recall right. We kept their diets to no more than 35%
protein, given their histories, made sure they stayed hydrated, and
monitored the things like their urine pH for at least the first year.
One of the two developed insulinoma but that was very near the end of
life. The other never got it. (We normally have about 20% of our
ferrets get any of a range of pancreatic diseases in life, with
insulinoma being the largest type in that mix.)
Sukie (not a vet) Ferrets make the world a game.
Recommended ferret health links:
all ferret topics:
"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)
A nation is as free as the least within it.
[Posted in FML 8056]