Could humans (or any animal) aquire the ability to synthetize Vitamin D from simpler compounds without UV? I'm curious.

OT - and only because your English is amazingly good for a non-native speaker - the word is synthesise or synthesize

http://www.researchgate.net/post/How_do_nocturnal_animals_handle_their_metabolism_with_lack_of_sufficient_vitamin_D

 

No real answer here - but interesting points.

 

I looked at ergocalciferol - cos I know you get that in mushroom (known for growing in v low light) but cannot see much of interest apart from fact that lighting mushroom with UV increases the yeild

It might be possible, but keep in mind that we consume the pre-precursor in plenty quantities and is present in the cellular membrane as a sort of plasticizer: cholesterol. A couple of dehydrogenations and a UV-activated reaction gives you vitamin D.