Further Studies of the Effect of Linoleic Acid on Reproduction in the Hen

Abstract

Single Comb White Leghorn female pullets were reared from hatching to 25 weeks of age with a low fat purified diet calculated to contain 0.005% linoleic acid (18:2). The pullets were then distributed into 6 groups of 20 birds each and given safflower oil at increments calculated to furnish zero, 10, 20, 40, 80, and 250 mg of 18:2/bird/day respectively. An increase in egg production, egg size, fertility and hatchability paralleled an increase in dietary 18:2 with the exception that hatchability still remained zero at the 10-mg level. Only 20 mg of 18:2 daily were necessary in this extracted, purified diet to increase fertility from 73.4 to 92.5%, and to decrease early embryonic mortality from 31.0 to 10.8%. Higher levels of 18:2 had no further effect on fertility or early embryonic mortality. The presence of quantities of eicostrienoic acid (20:3) in the plasma and yolk lipids from essential fatty acid-deficient hens suggests a possible relationship between the development or expression of the various reproductive characteristics and the tissue level of 20:3. The levels of the 20:3 acid in the tissues decreased with each increase in dietary 18:2. These changes were reflected by increases in egg size, egg production, hatchability, and decreased early embryonic mortality.