E isn't good enough. Third, tuna does contain high amounts of mercury and is systemically poisonous due to heavy metal intoxication. It is believed that an overabundance of unsaturated fatty acids in the food, together with a deficiency of vitamin E, results in the deposition of the pigment in the fat. Affected cats are frequently plump and well fed, usually young, and may be of either sex. They show loss of agility and general unwillingness to move.
Resentment is exhibited on palpation of the back and abdomen.
In the advanced cases, even a light touch will cause pain. Fever is a constant finding and anorexia may be present. Biopsy of the subcut. Microscopic examination reveals severe inflammatory changes and associated ceroid pigment. The administration of vitamin E, in the form of a-tocopherol, at least 30 mg daily for cats, or 15 mg daily for mink, is necessary.