Chloride requirement of kittens for growth is less than current recommendations

The minimal chlorine (chloride) requirement of kittens for growth was determined in a study in which kittens were given purified diets containing 0.1, 0.4, 0.7, 1.0 or 1.3 g of chloride (Cl) as KCl/kg diet. Each dietary group contained six (three males and three females) specific-pathogen-free kittens; the diets were fed for 30 d. Kittens receiving diets with <0.7 g Cl/kg became alkalotic as evidenced by an increase in blood pH, blood bicarbonate, standard bicarbonate, actual base excess, standard base excess, partial pressure of carbon dioxide (pCO(2)) and total CO(2). In addition, kittens were hypochloremic and hypokalemic; they had decreased serum ionized calcium and a negative chloride balance. On the basis of the chloride balance measurements, a broken-line nonlinear least-square analysis predicted a Cl requirement as 0.89 g Cl/kg diet (22 kJ/g diet). Because the dietary Cl concentration closest to 0.89 g/kg that we tested was 1.0 g Cl/kg, we recommend a minimum chloride requirement of 1.0 g Cl/kg diet for growing kittens. This value is considerably less than the recommended chloride requirement of the National Research Council of 1.9 g Cl/kg diet, or the allowance of the Association of American Feed Control Officials of 3.0 g Cl/kg diet. Because the bioavailability of chloride is high, the previous estimates appear excessive.