Here's a feeding mixture I really like. My vet told me to syringe it in, opening the dragon's mouth from the very front, so as not to damage the teeth. I use this if Isabel loses her appetite from coccidiosis treatment.
From beardeddragon.org:
http://www.beardeddragon.org/articles/parasitecare/
If, during this treatment period, your dragon has stopped eating entirely, or if you are concerned that he is dropping too much weight, you can syringe feed him a formula which is super nourishing until he starts eating again on his own.
To make this formula, you will need to purchase a tube of "Jumpstart", which is a caloric supplement and reptile appetite stimulant that comes in a paste form. This product is made by Zilla Reptile, and can sometimes be difficult to find in Pet Stores. If you aren’t able to purchase it locally, you can purchase it online at ReptileSupply.com. It can be found under reptile appetite stimulants. This product was formerly manufactured by ESU Reptile, who have now sold the rights for it to Zilla.
Mix about a teaspoonful of the “Jumpstart” paste with a jar of Gerber #2 Chicken Baby Food, a pinch of your beardie’s vitamins and of his calcium supplement, and some Pedialyte (like you give small children when they have diarrhea). Mix everything up but the Pedialyte, and then add just enough Pedialyte so that it flows easily through the tip of the syringe. I would recommend using the Cherry or Orange flavored Pedialyte, since the unflavored Pedialyte tastes really unpleasant!
Try to get two or three teaspoonfuls of this formula into him at least once a day (or a smaller amount, if your dragon is still a small baby). This amount will provide him with the protein that he requires (from the baby food), and all the vitamins that he needs (from the Jumpstart) until he starts feeling better and begins to eat again on his own.
