Amino Acids in the Production of Chicken Egg and Muscle

ALTHOUGH vegetable proteins can be produced more cheaply and efficiently, soybean protein being outstanding in this respect, in terms of agricultural resources eggs and chicken are second only to whole milk as economical sources of animal protein for human beings (Anonymous, 1944; Harding, 1944). The protein of eggs has long been regarded as superior in nutritive quality, and recent studies have demonstrated that the proportion of essential amino acids apparently is ideal (Harding, 1944; Sumner, 1938). During the development of the embryo there is adequate material to produce such diversified proteins as muscles, organs, immune bodies, hormones, blood, and cartilaginous and keratin proteins. As Sherman (1933) has pointed out, “the nature of the nutrients in eggs is of almost as much interest and importance as their amount. The fact that when an egg is kept at a proper temperature for about three weeks without the addition of anything from without, . . .