GROWTH AND ESSENTIAL FATTY-ACID LEVELS OF PLASMA AND LIVER OF SUCKLING RATS FROM MOTHERS FED ON FAT-FREE OR VARIOUS FAT DIETS

The milk fatty acid compositions of mothers fed on a fat-free or vario us fat diets, and the effects on growth and fatty acid compositions of their pups were studied. Even the milk of essential fatty acid-defici ent mothers fed on a fat-free or hydrogenated fat diet contained about 3 and 1.7%, n-6 and n-3 fatty acids, respectively. In the plasma of t he suckling pups, however, the proportions of n-6 and n-3 fatty acids rapidly increased to about 20 and 3-5%, respectively, at 1 week after birth. In particular, the PUFAs markedly increased in the liver PC and PE, and the high levels were maintained until weaning. Although the P UFA compositions of suckling pups were influenced with those of matern al diet, small amounts of n-6 and n-3 fatty acids were usually maintai ned in the plasma and liver. After weaning to the same diets (without PUFAs) as the mothers, however, the n-3 and n-6 fatty acids rapidly de creased and endogenous n-9 eicosatrienoic acid appeared. On the other hand, the growth during suckling was not significantly different among the litters of mothers fed on diets with or without n-3 or n-6 fatty acids. After the weaning, however, the growth was improved in the foll owing order: corn oil, perilla oil > fish oil > fat-free, hydrogenated fat diet group. n-3 fatty acids appeared to be used partially as subs titutes for n-6. However, the essentiality was not clear, as the n-3 f atty acids always coexisted with the n-6. Thus, it appeared that small amounts of n-3 and n-6 fatty acids in milk were supplied to the suckl ing animals regardless of maternal diet and supported growth.