I'd forgotten but when my baby bp wasn't eating and losing weight the vet suggested repta-aid which you can syringe into their throats, not a food substitute but can sometimes help to regain an appetite in an animal who's system is out of whack. It's a powder you mix with water and it comes with the syringe and stuff, also if you do end up getting it make sure to not put the liquid in where she breathes but way at the back of the throat.

http://www.amazon.com/Laboratories-R.../dp/B001EUI246