Morphologic Effects of Dietary Plant and Animal Lipids Rich in Docosenoic Acids on Heart and Skeletal Muscle of Cynomolgus Monkeys

Cynomolgi (Macaca fascicularis) were fed diets containing 25% rapeseed oil (RSO), partially hydrogenated herring oil (PHHO), or a 3:1 mixture of lard and corn oil as control for 4 months. The RSO contained approximately 25% of the fatty acids as erucic acid; the PHHO contained a similar concentration of mainly cetoleic acid. The control diet did not include such fatty acids. At the time of necropsy, the RSO- and PHHO-fed monkeys showed myocardial and skeletal muscle lipidosis. Foci of mononuclear cell infiltration, although infrequent, occurred in all three groups and were thought to be nonspecific. The only significant intergroup difference in serum biochemical or hematologic parameters was an increase in serum glutamic-oxaloacetic transaminase activity in both RSO and PHHO groups. Ultrastructural studies confirmed the presence of lipidosis in cardiac and skeletal muscle and revealed mild mitochondrial degeneration, causing a depression of the P/O ratio of the RSO group and a State III respiratory rate depression of the PHHO group. The difference in the exposure/life span ratio represented by this experiment may account for the absence of clear intergroup differences such as are reported in rats used in similar studies, but a true species difference in regard to dietary oils containing docosenoic acids has to be considered as well.