Dietary Requirements for Reproduction

In connection with his studies on the r81e of proline in nutrition, begun at the Department of Agricultural Chemistry, University of Wisconsin, in 1918, the author became interested, from work then in progress, in the supplementary value of lactalbumin to casein, fed in the same proportions &I these proteins are found to occur in milk.In the series of experiments initiated in the early part of 1919 (1) skimmed milk powder, fed at a 9.6 per cent level, was found to be excellent for growth, but was found, in the presence of a suitable salt mixture and an abundant supply of the known vitamins, to be inadequate for reproduction.The cause for failure was attributed to the possibility that the amino acid requirement of the mammalian organism for the physiological processes of fertility and lactation may be different from the requirement for growth, from the standpoint either of quantity or of quality, and so for 2 years experiments to elucidate the failure of reproduction on diets composed of purified food substances were conducted from the amino acid standpoint.Later on, after the quality of the protein in the diet had been improved, intensive efforts to produce fertility and to obtain success in lactation by increasing the known vitamins in the diet resulted in failure.No attempts were made to improve the nature of the inorganic ion complex of the synthetic diets.In these experiments it was found that the addition of one seed to the pure diets always resulted in fertility and, in a good many cases, fair success in rearing of young was secured.