apple twigs for rabbit

Question
I came across a reply from rabbit "expert" Lee Meyer (currently "maxed out
and not answering questions) that basically said apple twigs fed to rabbits
must be dry to be safe (no further explanation as to why). Can you explain
why? I've been feeding fresh twigs for some time to rabbits without noticeable  
effect. I know for a fact wild rabbits will go to great length to eat fresh twigs.
So, what exactly is the danger?

Answer
Dear John,

Many plants in the genus Malus and Pyrus (apples and pears, respectively) have low levels of cyanide in their tissues, though it is most highly concentrated in the seeds.  The level of cyanide in the tissues will vary, depending on where the trees are grown, soil content, climate, etc.  

Cyanide content in Pyrus/Malus stems is usually quite low (if it's present at all), but many people prefer to err on the side of caution and not feed fresh apple or pear twigs to their bunnies.

Drying or baking the twigs apparently volatilizes any cyanide, making the twigs a safer treat.  (But I'd still not feed any apple or pear seeds to my bunnies.)

You can find a good veterinary overview of cyanide poisoning here:

http://web.vet.cornell.edu/CVM/HANDOUTS/plants/cyanide.html

It also includes a list of plants commonly associated with cyanide poisoning.

Hope that helps.

Dana