Although white fish is a good source of nutrients for your cat, a diet consisting largely of tuna is poor. A tuna-only diet could be lethal. Firstly tuna is top of the food chain in the planet’s oceans. The fish contains high levels of man-made pollutants.
In addition and importantly, tuna contains an enzyme called thiaminase, which destroys the B1 vitamin, thiamine, resulting in thiamine deficiency. It actually breaks it down into two molecular parts. This can result in your cat suffering from a painful life-threatening condition called pansteatitis also called steatitis.
Although fresh and tinned tuna is okay as a small part of a cat’s diet it should not be the diet. In fact, human grade tuna should be feed to your cat infrequently despite the fact that some cats find it almost addictive. Cooking tuna destroys thiaminase which protects thiamine.
Tuna is an inadequate source of vitamin E. Also tuna contains high levels of unsaturated fatty acids which oxidise and destroy vitamin E.
This combination of events leads to damage of the cat’s body fat and an inflammatory response.
Diagnoss is through knowing the cat’s dietary history and a biopsy of the cat’s fat. The symptoms are fever, anorexia, dull coat, flaky skin, severe pain when touched and no desire to move.
The treatment naturally involves an immediate change to a no-fish diet and vitamin E supplements. Other treatments may be necessary per the vet’s advice.
A tuna diet is the most common cause of pansteatitis in cats.