Effects of dietary acidification and potassium depletion on acid-base balance, mineral metabolism and renal function in adult cats.

Effects of dietary potassium restriction, with or without dietary acidification, on acid-base balance, mineral metabolism and renal function were evaluated in 12 adult cats. Six cats were fed a potassium-restricted diet (0.2% potassium) for 8 wk, and six cats were fed the same potassium-restricted diet plus a dietary acidifier (0.8% NH4Cl) for 8 wk. Both groups of cats were then fed the same diet supplemented with potassium gluconate (0.7% dietary potassium) for an additional 4 wk. Renal function was evaluated before treatment and again at 8 and 12 wk. Serum potassium concentration declined in all cats by wk 1 and was also lower in NH4Cl-treated cats at 2, 3, 6 and 8 wk than in control cats. Metabolic acidosis developed in both groups of cats. Dietary balance studies indicated negative potassium balance in NH4Cl-treated cats. Glomerular filtration rate declined significantly in NH4Cl-treated cats after 8 wk but was unchanged in control cats. From the results of this study, we conclude that adding a dietary acidifier to a potassium-restricted diet worsens hypokalemia, possibly by affecting gastrointestinal potassium handling, and induces severe metabolic acidosis and renal dysfunction in adult cats.