My dog has a gurgling sound from his stomache area?

my dog is about 5 years old. hes in good health but he has some serious knee problems. so he is on a Steroid. it give him incredibly horrible gas. but now he has this very loug gurgling noise in his tummy, when I put my hand on his tummuy to feel it it feels like there is water rushing. my husband things it correlates with his breathing, but he doesnt seem to be in any pain or any discomfort so I am not worried about a twisted stomach, could it just be gas moving around in there, or does anyone know about any side affects from steroids like a perforated stomach or anything like that?