Assessment of tissue distribution and concentration of b-cryptoxanthin in response to varying amounts of dietary b-cryptoxanthin in the Mongolian gerbil

There is a general lack of knowledge regarding the absorption and tissue storage of the provitamin A carotenoid b-cryptoxanthin. The present study investigated the whole-body tissue distribution of b-cryptoxanthin in an appropriate small animal model, the Mongolian gerbil (Meriones unguiculatus), for human provitamin A carotenoid metabolism. After 5 d of carotenoid depletion, five gerbils were euthanised for baseline measurements. The remaining gerbils were placed in three weight-matched treatment groups (n 8). All the groups received 20mg/d of b-cryptoxanthin from tangerine concentrate, while the second and third groups received an additional 20 and 40mg/d of pure b-cryptoxanthin (CX40 and CX60), respectively, for 21 d. During the last 2 d of the study, urine and faecal samples of two gerbils from each treatment group were collected. b-Cryptoxanthin was detected in the whole blood, and in twelve of the fourteen tissues analysed. Most tissues resembled the liver, in which the concentrations of b-cryptoxanthin were significantly higher in the CX60 (17·8 (SEM 0·7)mg/organ; P1⁄40·004) and CX40 (16·2 (SEM 0·9)mg/organ; P1⁄40·006) groups than in the CX20 group (13·3 (SEM 0·4)mg/ organ). However, in intestinal tissues, the concentrations of b-cryptoxanthin increased only in the CX60 group. Despite elevated vitamin A concentrations in tissues at baseline due to pre-study diets containing high levels of vitamin A, b-cryptoxanthin maintained those vitamin A stores. These results indicate that b-cryptoxanthin is stored in many tissues, potentially suggesting that its functions are widespread.