OPTIMAL GROWTH OF THE RAT

Abstract

Rats, rat organs and chemical components of rats grow (increase in wt. or other dimensions) at rates or in proportions which are considered to be sub-optimal, adequate or near-optimal. The straight lines derived from plots of logarithms of weights or lengths and the reciprocals of time appear to provide satisfactory, although empirical, bases for the evaluation of growth of rats and the relative efficiency of exptl. diets. Rats of three strains appear to have widely different limiting weights which represent strain differences necessary to consider in growth expts. Although voluntary exercise and temp. affect gain in body wt. of [female] rats significantly on su]b-optimal diets it is not known to what extent growth on near-optimal diets would be influenced by these factors. No abnormalities in the growth of rats, rat organs and chemical components of rats maintained on the Anderson-Smith diet have been observed. This diet is superior to the other diets for which exptl. data are available in promoting high quality growth and reproductive performance of rats. It is concluded as a working hypothesis that the Anderson-Smith diet contains the types and proportions of chemical substances which are near-optimal for the growth of body, organs and body components and for the reproduction of the rat. No information is available on the efficacy of this diet in promoting longevity, resistance to disease and physiological well-being as detd. by other criteria.