Caprenin, a randomized
triglyceride primarily comprising caprylic (C8:0), capric (C10:0), and behenic (C22:0)
acids, was administered in a semi-purified diet to weanling Sprague-Dawley rats (25/sex/group) at dose levels of 5.23, 10.23 or 15.00% (w/w) for 91 days.
Corn oil was added at 8.96, 5.91 and 3.00%, respectively, to provide
essential fatty acids and digestible fat calories.
Corn oil alone (12.14%) and a blend of medium-chain
triglyceride (MCT) oil plus
corn oil (11.21 and 3.13%, respectively) served as controls. All diets were formulated to provide about 4000 kcal/kg of diet and 26.8% of digestible calories from fat by assuming that
corn oil, MCT oil, and
caprenin provided 9, 7 and 5 kcal/g, respectively. Survival, clinical signs,
body weight, feed consumption, feed efficiency, organ weights, organ-to-
body-weight ratios, organ-to-brain-weight ratios, haematological values and clinical chemistry parameters were evaluated in all groups. Histopathology of a full
complement of tissues was evaluated in the
corn oil and MCT oil control groups as well as the high-dose
caprenin group. Additional rats (n = 5/sex/group) were included in the study to determine whether there was marked storage of C22:0 in heart, liver or perirenal fat at the end of the 91-day feeding period. No significant differences in
body weight gain were measured with the balanced caloric diets, although feed conversion efficiency was reduced in the high-dose
caprenin group. No adverse effects from the ingestion of
caprenin were detected, nor were significant amounts of C22:0 present in the fat extracted from the selected fat depot sites. These results establish a no-observable-adverse-effect level (NOAEL) of more than 15% (w/w)
caprenin in the diet (or more than 83% of total
dietary fat), which is equal to a mean exposure level of more than 13.2 g/kg/day for male rats and more than 14.6 g/kg/day for female rats.