Proline Essentiality and Weight Gain

Abstract

ALMQUIST and Grau (1944) classifled proline as a dispensable amino acid for the growing chick since deleting this amino acid from their crystalline amino acid diet did not impair growth. Similarly, Benton et al. (1955) and Adkins et al. (1952) observed no significant growth response when proline was added to crystalline amino acid diets. In contrast, earlier studies conducted in this laboratory (Klain et al., 1959; Greene et al., 1962) and a recent study in Japan (Sugahara and Ariyoshi, 1967) showed improved gains upon the addition of proline to crystalline amino acid diets. Roy and Bird (1959) also noted a small increase in growth when a practical diet was supplemented with proline. Klain et al. (1959) were led to comment that while proline could be synthesized by the chick, the rate was not commensurate with the need for rapid growth. This explanation fits Rose’s definition of an indispensable dietary component…