what can you do if your dog don't want to eat?

Cat food.

Thats like a pizza to a human.

Well,dear lady,i'm not being facetious or critical but since you're a Petlover, please consult your vet asap if you haven't already done so. All my best to you and your beloved baby.

is it a recent development? have they shown picky behavior in the past? your dog could be sick

take him for a long walk and see if that gets his bowels working and he might get hungry too

If it's more that 24 hours...see a vet.