The male preruminant, Holstein calf was utilized in a variety of studies as a model for the absorption of 9-cis β-carotene (βC) into whole serum, lipoprotein fractions and tissues. Either 20 mg of crystalline 9-cis βC in oil or 20 mg all-trans βC as 10% water soluble beadlets (both gifts from Hoffmann La Roche Inc.) was provided as part of their morning meal. Some calves were fitted with jugular and portal catheters. Whole serum, chylomicron, VLDL and LDL, and HDL fractions were analyzed by HPLC for 9-cis and all-trans βC. Two calves each were killed 48 hours post 9-ds or all-trans dose and tissue all-trans : 9-cis ratios were determined. High ratios were found in adrenal, kidney and adipose (3.07, 2.21 and 2.15, respectively). Lower ratios of 1.05, 1.29, and 1.36 were found in liver, lung and spleen. In a second study focusing on serum βC profiles, small increases in 9-cis βC (up to 15 nmol/L) occurred and were limited to the first 9 hours post-dose. All calves showed evidence of an immediate drop in serum all-trans βC within hours after dosing with 9-ds βC followed by a recovery to pre-dose levels or a small increase in all-trans βC (up to 168 nmol/L). In the final study, one male Holstein calf was fed a meal of 9-ds βC extracted from Betatene™ in oil. Serum profiles concur with the crystalline 9-cis βC calves. However, tissue levels of both 9-ds βC and all-trans βC were higher than those of calves fed 9-cis βC from the crystalline source. This study suggests that there is minimal uptake of 9-cis βC into calf serum and that the 9-cis βC that is absorbed is rapidly cleared by liver and other tissues in the calf.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology