Leucine and Fowl Ascarids

IT HAS been repeatedly shown that protein in a diet influences the degree of resistance of a fowl to parasitism (Ackert and Beach, 1933; Luttermoser and Allen, 1942; and Riedel and Ackert, 1950, 1951). Almquist and Grau (1944) presented some results which indicated that a mixture of amino acids in the diet of a growing chick could replace a protein supplement. Relative to parasites Riedel (1950) reported that lysine was not effective in protecting the fowl from the parasite Ascaridia galli, and Todd (1951) found more and larger roundworms when chicks were fed a high methionine diet. Riedel (1954a) stated that sufficient tryptophane to promote host growth did not influence higher resistance to the chick ascarid. In another investigation it was found that glycine at a growth promoting level in the diet of a chick encouraged parasite length, but it did not alter the number of parasites harbored (Riedel, 1954b).