Cats are carnivorous creatures and are unlikely to be interested in or able to digest apples in large amounts. However, only the seeds, core and stem are harmful for cats because they contain toxic chemical compounds.
Cats may enjoy apples that are pureed or chopped and given as a treat or added to their meals. Low-calorie, low-fat and filled with minerals and vitamins, apples can boost the immune system, help with weight management and reduce the health risks of aging.
Other fruits and vegetables that a cat may enjoy include blueberries, strawberries, seedless watermelon chunks, carrots, sweet potatoes and catnip. Cooking should be limited to baking or steaming, and treats should be served without seasonings or butter. Owners should never feed a cat garlic or onions, even in minute forms, and should always remove the pit from any fruit.
Although cats like seafood, raw fish can cause gastrointestinal upset. In more severe cases, the protein thiaminase in raw fish can break down thiamine, an essential vitamin B, and in the long term lead to neurological impairment and convulsions. Bones can have equally disastrous results. When cooked, they can splinter and pierce the intestinal wall or cause blockages. Even the act of chewing on bones can cause injury if the bone is too hard and causes dental damages.