Nutritional problems in cats: taurine deficiency and vitamin A excess

Two nutritional problems of the cat are reviewed. One represents a deficiency of taurine, the other vitamin A toxicity. Taurine deficiency in cats is insidious because the progressive retinal degeneration induced may go unnoticed until the damage is advanced and irreversible. Both rods and cones undergo degeneration along with the underlying tapetum lucidum. The hyperreflective focal lesion is easily observed in the area centralis with an ophthalmoscope and has been previously identified as feline central retinal degeneration. This lesion is not reversed by taurine supplementation, even though the remaining retina may be saved from further degeneration. The cat requires dietary taurine, found in meat and fish, because it cannot synthesize enough to meet demands for bile acid conjugation and tissue metabolism, especially those of muscle and central nervous system. Vitamin A toxicity is not commonly observed in cats but may occur if cats are fed beef liver in which appreciable vitamin A is stored. Cats exhibit muscle soreness and hyperesthesia, especially along the neck and forelimbs where bony exostoses of cervical verterbrae and longbones are common. The diagnosis is readily made from radiographs. The response to removal of vitamin A from the diet is generally rapid and, unless the toxicity has been chronic in young kittens, recovery is generally satisfactory.