Reproduction in Laboratory Animals as a Measure of the Value of Some Natural and Processed Foods

Summary. (I) Four different experiments on the effects of natural diets on reproduction are presented. (2) In the first experiment reproduction of mice on wheats grown under different systems of soil management showed that, even on a sub-optimal diet, small differences in composition may influence the results of reproductive tests, and that the effects may differ in the male and female mouse. (3) In the second experiment a raw heart diet which might be considered to be a `natural' food for carnivores was shown to be totally inadequate for reproduction due to mineral deficiencies. (4) In the third and fourth experiments the effects of canned diets on the growth of the genital tract in the female cat and on reproductive performance were examined. From these it was concluded that depression of appetite, resulting in an inadequate intake of calories derived from protein, delayed the maturation of the genital tract and gave a poor reproductive performance.