i LOVE informed workers at a petstore! they are not nearly enough of them!!
i don't know about vegitable oil. i know olive oil is great... here is what we do.. i break open a fish oil capsule (That a human would take) and i put about half of it in wet food for layla.. this way it isn't sitting on her food all day and i know she has taken the full amount.. in this wet food she also gets her missing link and some fibre