I'm new to this board so don't know your entire situation and as to why you are having to syringe feed but, why not ask your vet for some cyproheptadine. It is a drug that is known to stimulate the appetite, although this isn't what it was originally prescribed to do. There is an assisted feeding group at yahoogroups.com. Also ask your vet for AD which is calorie dense, smooth, and cats seem to like the taste. It can be syringed.

Are you a member of the feline ibd list?