Nutrient reqirements of rats and mice

CONCLUSIONGrowth, as measured by weight gain, and reproductive performance are the most common factors used in assessing a diet.Often reproductive performance is given on the results with one or two litters.The desirability of rapid growth has been a dominant idea in current nutritional thought, and recent discoveries have resulted in feeding practises that have accelerated the growth rate as measured by weight gain.However, some animals with a promising growth performance fail to come into profitable production, or have a short reproductive life.It cannot be said that all factors for growth are optimal until their influence on the life-time performance has been studied as thoroughly as their effects during the growth period itself.It would seem that in the past too much emphasis has been put on weight and size in judging the value of a diet for promoting growth with less consideration of the actual composition of the changes in form.With breeding stock the life-time performance is the final measure of success and it is important to consider several aspects of growth and their influence on the life-time performance.Therefore before a diet can be described as being adequate for maintenance and reproduction it should be tested through all these aspects.I should like to thank Dr W. Lane-Petter and Professor B. S.