Originally Posted by ddcats
My cats get their vitamins from the quality dry food.
Cats in the wild are scavengers who eat anything: mice, rabbit, moles, birds, insects, fish, etc.
I know my cats are happy without any health problems.
It would be nice to have some documentation showing the statistics of cats who were fed tuna exclusively for years and the damage it caused.
The previous poster's cat lived to be 20 without any problems.
The previous poster is one instance, and probably did not eat only tuna. Cat's are not scavengers. Scavengers are animals that eat dead carcasses. Cat's are hunters that instinctively seek out prey that will fulfill their nutritional needs. Since they were descendent from desert creatures - where no fish are present - they never ate fish on a regular basis. As such, their biology adapted to survive without it.
Taken from Mindy Bough, veterinary technician for the ASPCA Pet Nutrition and Science Advisory Service.Tuna does not contain significant amounts of vitamin E, for example, so too much of the fish can lead to vitamin E deficiency, resulting in yellow fat disease, or steatitis. Symptoms include loss of appetite, fever and hypersensitivity to touch, due to inflammation and necrosis of fat under the skin. Felines who are fed too much tuna can develop other nutrient deficiencies, too, because most de-boned fish are lacking in calcium, sodium, iron, copper and several other vitamins. Without proper care, steatitis can cause death. Mercury, frequently present in tuna, also presents a potential danger.
The human variety of tuna fish contains an enzyme that destroys vitamin B1 (thiamine). Cats who regularly eat tuna can develop a vitamin B1 deficiency, which results in neurological symptoms like dilated eyes, loss of equilibrium, seizures and death if this vitamin is not replaced. The scientific name of this disease is polioencephlomalacia.
Tuna also lacks sufficient amounts of Taurine, which is essential to feline health. The calcium to phosphate ratio is also out of balance for what a cat needs.
Just google "tuna for cats", or consult your vet. You'll find the same information. Occasional tuna is ok, but feeding long term and exclusively will cause problems.