Studies of the Metabolizable Energy of Cottonseed Meals for Chicks, with Particular Reference to the Effects of Gossypol

THE nutritive value of cottonseed meal for chickens and other non-ruminant species is influenced by at least four factors. The toxicity of gossypol has been long recognized; the minimum dietary level of gossypol which is detrimental to growth and development has been reported to be as low as .016 percent (Heywang and Bird, 1955) and as high as .08 percent (Couch, Chang and Lyman, 1955) and has been shown to vary with the level of dietary protein (Narain et al., 1960). The relative lysine deficiency of cottonseed protein is also well established, and this may be further aggravated by reaction of lysine with gossypol and other constituents of the seed during processing (Kuiken, 1952). A third factor is the extent of heat damage to the protein during processing, as suggested by the general correlation of nutritive value with protein solubility (Lyman et al., 1953). The development by genetic selection of…