Although a diet including or consisting of fish is not natural for the domestic cat, could a diet of fish nonetheless meet the nutritional needs of the cat?
Canned Tuna is among the most popular food stuff to feed to companion cats, because cats are very fond of it. It is not uncommon for cats, that regularly receive tuna, to refuse all other foods. Cats displaying this addiction-like behaviour are often referred to by Veterinarians as “tuna junkies”. Feeding a mainstay of canned tuna is long known to cause diseases of dietary origin. One of the most prevailing diseases afflicting “tuna junkies” is Steatitis or Yellow Fat Disease – an inflammation of the fat tissue in the body due to a deficiency of vitamin E. A vitamin E deficiency is usually the result of feeding tuna, or any canned fish, packed in vegetable oil. These products are high in polyunsaturated fatty acids which oxidate vitamin E, besides being a poor source of vitamin E to begin with. Currently, a diet consisting of large amount of any type of fish is considered the most common cause of this syndrome.
Canned fish- tuna or other, packed in water or oil – is not a complete diet for cats. Although it is high in protein, it does not supply the cat with sufficient amounts of certain amino acids, mainly taurine, to maintain health. The Calcium to Phosphorus ratio in canned tuna is 1:14.8 [2.] – providing the cat with too little Calcium to balance Phosphorus, resulting in bone disease caused by a loss of Calcium in the bone due to a deficiency of this mineral in the diet. The only canned fish providing sufficient Calcium is salmon with bones. Many essential vitamins are not provided in sufficient amounts through a diet of canned fish, such as vitamin A and most B vitamins, like Thiamin, Riboflavin. Pantothenic Acid, Folic Acid, and Vitamin B-12. Last but not least, canned fish is high in sodium, possibly providing the cat with too much of this mineral.