Retention of linoleic acid in carcass lipids of rats fed different levels of essential fatty acids.

Rats of an inbred Sprague-Dawley strain were fed purified diets with low (0.3% of total energy), normal (3%) or high (10%) content of essential fatty acids (EFA) for at least three generations. Two 30-day-old rats with similar weights were chosen from one litter. One was killed; weight increase and food consumption of the other rat was measured for 15 days. Total lipid content and fatty acid composition in total lipid and lipid classes were determined in both rats. Seven pairs of rats from each group were treated in the same way. Calculations based on amount of linoleic acid ingested and retained in the carcass lipids showed that 50% of the ingested linoleic acid was retained in the low EFA rats compared to 10-15% in the normal and high EFA rats.