The mongolian gerbil (Meriones unguiculatus) is an appropriate animal model for evaluation of the conversion of beta-carotene to vitamin A.
Vitamin A (VA) deficiency is the leading cause of blindness in children in developing countries. Dietary intervention with foods rich in provitamin A carotenoids, such as beta-carotene (betaC), has been suggested as one solution to this problem. The objective of the two studies described in this paper was to examine the utilization of betaC as a source of VA at different stages of VA depletion using the Mongolian gerbil as a model. Male 4- to 5-wk-old Mongolian gerbils were fed powdered betaC-free semipurified diets either with or without VA for 26 d (Study 1), or without VA for 8-10 wk (Study 2). Gerbils were then fed diets with or without VA (20.9 nmol/g diet) and/or betaC [(67.0 micromol/g diet (Study 1) and 145.9 micromol/g diet (Study 2)] for variable periods. Two (Study 1) or three (Study 2) days before termination of the study, 3-4 gerbils per group were dosed orally with 14C-betaC. Tissues were evaluated for VA and betaC content by HPLC. Liver was extracted with and without saponification to evaluate 14C-betaC and 14C-VA content. The results demonstrate the following: 1) the gerbil is an appropriate animal model to study betaC utilization; 2) 20.9 nmol VA/g diet is more than sufficient for this species; 3) the daily VA utilization rate for this species is calculated to be 3.1 microg/100 g body weight; 4) a highly bioavailable source of betaC at a 6:1 weight ratio of betaC:VA is sufficient to reverse marginal VA status in this model; and 5) a highly bioavailable source of betaC fed between a 6:1 and 13:1 weight ratio to VA provides equivalent VA status as preformed VA in Mongolian gerbils.
Lee
C M
CM
Department of Food Science and Human Nutrition, University of Illinois, Urbana, IL 61801, USA.
Lederman
J D
JD
Hofmann
N E
NE
Erdman
J W
JW
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D004338:Drug Combinations; D005849:Gerbillinae / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D014018:Tissue Distribution; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D014802:Vitamin A Deficiency / Q000378:metabolism*; D019207:beta Carotene / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics
D004338:Drug Combinations; D019207:beta Carotene; D014801:Vitamin A