Cats are obligate carnivores, and it is a well established fact that carnivore intestinal gas has a different, more pungent odor than herbivores. If you are noticing excessive gas, or if the farts are accompanied by other symptoms, such as vomiting, diarrhea, weight loss, then it could indicate an underlying problem. Digestive issues, sensitivity to ingredients, intestinal parasites, and other health conditions can all contribute to excessive gas - if you are concerned, please consult with your local veterinarian.