Studies of Essential Fatty Acid Deficiency of the Growing Domestic Cock1'2

PROBABLY the earliest report of an un-complicated essential fatty acid (EFA) deficiency in chicks was Bieri et al. (19S6). These workers reported obtaining a very small growth response to added fat when chicks were fed a purified low fat diet for 10 to 12 weeks. Rand et al. (1958) and Dam et al. (1959) then presented evidence indicating that the chick would respond to fat supplementation during the first few weeks. The two groups of workers inter-preted their results quite differently; how-ever, Rand et al. (1958) interpreted their results to indicate a nonspecific response to fat probably due to protein sparing while Dam et al. (1959) interpreted their results as indicating the need for some unknown factor in the oil (possibly an essential fatty acid). Machlin and Gordon (1961) con-ducted studies indicating that methyl lino-leate had the same activity as safflower oil in promoting growth of chicks, while meth-yl linolenate did not have this growth promoting effect in a short term test. These workers also showed that the chick is similar to the rat in that it accumulates eicosatrienoic acid (20:3) in the tissues (adipose tissue is an exception) when fed a fat deficient diet, and that when linoleic acid is fed, the eicosatetraenoic acid, arach-idonic acid (20:4) is present in high concentration in all tissue except adipos