Retinal and brain accretion of long-chain polyunsaturated fatty acids in developing felines: the effects of corn oil-based maternal diets

Abstract

A study was carried out in domestic felines to determine whether corn oil-based maternal diets are an adequate source of essential fatty acids to support normal accumulation of long-chain polyunsaturated fatty acids in the brains and retinas of offspring and whether these diets have any subsequent effect on visual function. Female domestic felines were acclimated to one of six different defined diets 1 mo before mating and maintained on the diets throughout pregnancy and lactation. Four diets contained only corn and hydrogenated coconut oils as their source of fat in ratios of 1:9, 3:7, 6:4, and 9:1, respectively. Two reference diets also contained the long-chain polyunsaturated fatty acids arachidonate (20:4n-6) and docosahexaenoate (22:6n-3). When the offspring were 8 wk old, electroretinograms were obtained and the a- and b-wave implicit times were determined. The results showed that animals raised in litters in which the maternal diets were devoid of 20:4n-6 and 22:6n-3 had an increase in a- and b-wave implicit times compared with the controls. In the rod outer segments and brains of these animals, there were lower amounts of 22:6n-3 and higher amounts of long-chain n-6 polyunsaturated fatty acids compared with control animals. These findings showed that although corn oil-based diets were capable of maintaining 20:4n-6 concentrations in the developing brain and retina, only those diets containing 22:6n-3 could support a high accumulation of docosahexaenoic acid in these tissues. Moreover, low amounts of 22:5n-6 in the brains of animals in all of the corn oil-diet groups suggested that young felines have a low biosynthetic capacity to produce this fatty acid or 22:6n-3. These findings suggest that in juvenile felines, maintenance of 22:6n-3 status in the nervous system is important for optimal retinal function.