Serum lipid and lipoprotein responses of six nonhuman primate species to dietary changes in cholesterol levels.

The response of serum lipids and lipoproteins to different levels of cholesterol in the diet was studied in chimpanzee (Pan troglodytes), rhesus (Macaca mulatta), green (Cercopithecus aethiops), patas (Erythrocebus patas), squirrel (Saimiri sciurea) and spider (Ateles sp.) monkeys. Five animals of each species were fed increasing amounts of dietary cholesterol (0.05% to 1.5% W/W) for 3-week periods; between each experimental diet, the animals were fed a basal diet without cholesterol for a similar period. Serum cholesterol response of different species measured in terms of response index (area under the time-concentration curve above basal value) varied with the dietary cholesterol content and showed a significant interspecies difference at 0.5% dietary cholesterol (1.8 mg/kcal) level. The overall response for the different diets allowed ranking of the species as follows: squirrel greater than green greater than spider approximately equal to rhesus approximately equal to patas greater than chimpanzee. The serum lipoprotein response was reflected not only in an increase in beta-lipoprotein but also in alpha-liprotein with significant differences among species in the amount of cholesterol transported in the lipoprotein classes. Challenging the animals with dietary cholesterol seems to be an essential step for determining inter- and intraspecies differences.