Influence of Methionine, Lysine and Tryptophan upon Food Intake and Production Responses in Laying Chickens

REVIEW OF LITERATURE FOR a long time it has been known that lysine and methionine are two of the most limiting amino acids in poultry feeds. Working with individual amino acids numerous workers have shown that supplementary lysine can improve the performance of birds fed low protein diets [Thorton et al. (1957), Waibel and Johnson (1961), Bradley and Quisenberry (1961), Harms and Waldroup (1962), and Sell and Hodgson (1966)]. Methionine supplementation on the other hand appears to be more beneficial at higher protein levels or in low protein diets which have already been supplemented with lysine (Barton and Stephenson, 1960; Harms and Waldroup, 1962; Sell, 1964; and Daghir et al., 1964). Biely and March (1964) and Smith (1967) have also demonstrated that supplementation with both lysine and methionine results in greater production, hatchability, egg size, egg weight and feed efficiency than with either amino acid. A third limiting amino acid…