In Ferret List Issue 767 [log in to unmask] writes:
 
>> From: John Rosloot <[log in to unmask]>
>>
>> On the subject of food, it's been stated that ferrets should be switched to
>> maintenance cat food around age 3-5 to reduce their protein intake and the
>> accompanying strain on their kidneys.
>
>   Our vet has told us that as long as the ferrets aren't getting
>too fat, the kitten chow is fine for them, regardless of age.
>So what's the deal? References please.
 
The most recent reference to this was in Ferret List Issue 753 (March 11):
 
>From: [log in to unmask]
>
>        Protein is the culprit.  Studies have shown over and over, that in cats
>and rats, two species which get similar renal lesions to ferrets, as they age,
>excessive levels of protein exacerbate renal disease, while mild protein
>restriction prolongs the life of the kidney.  Mind you, no one has ever done
>this study in ferrets - my info is based on looking at many, many kidneys of
>these species and noting the marked similarities in disease progression.
 
The first reference I'm aware of was in issue #710, and it's touched upon
again in #711, 713, 723 (in Part 9 of the FAQ), and 751.
 
John, Buddy, and Cassidy
 
[Posted in FML issue 0768]