Uptake of orally administered β-carotene by blood plasma, leukocytes, and lipoproteins in calves1

Abstract

The uptake of beta-carotene by blood cells, plasma, and lipoproteins was studied in bull calves that were orally administered a single (Exp. 1; n = 18 Angus calves) or multiple (Exp. 2; n = 16 Holstein calves) doses of beta-carotene. Administration of beta-carotene increased plasma beta-carotene and the amount of beta-carotene associated with each lipoprotein fraction. Before beta-carotene treatment, the total amount of beta-carotene associated with the high-density lipoprotein (HDL) was three- to fourfold higher than the amount associated with low-density lipoprotein (LDL) and fivefold higher than the amount associated with very-low-density lipoprotein (VLDL). The relative increase in total beta-carotene associated with the lipoproteins was greater for LDL than for HDL or VLDL. Orally administered beta-carotene increased the uptake of beta-carotene by lymphocytes. Subcellular fractions of blood lymphocytes isolated from animals fed beta-carotene revealed that beta-carotene was taken up in significant amounts by the mitochondrial, nuclear, and microsomal fractions. The profile of beta-carotene uptake by these subcellular fractions did not mirror that observed in plasma. In contrast, beta-carotene was not detectable in blood neutrophils and erythrocytes in either beta-carotene-supplemented or unsupplemented calves. Treatment did not influence the concentrations of retinol or alpha-tocopherol in plasma, lipoproteins, lymphocytes, neutrophils, or erythrocytes. These data revealed the presence of beta-carotene in bovine lymphocyte subcellular fractions and suggest a possible physiological role of beta-carotene in these cells.

Increasing pasture intakes enhances polyunsaturated fatty acids and lipophilic antioxidants in plasma and milk of dairy cows fed total mix ration

“…Our results and those from studies in humans [37], in which β-carotene was given as a supplement, indicate that an increase in plasma of β-carotene concentrations has minimal impact on plasma retinol concentrations. Chew et al [10] also reported that oral administration of β-carotene to calves fed a diet containing normal concentrations of vitamin A does not affect plasma retinol concentration.…”

Meeting the Vitamin A Requirement: The Efficacy and Importance ofβ-Carotene in Animal Species

“…In preruminant calves, oral supplementation with BC results in a plasma BC response [80, 83, 142, 143] as well as increases in tissue BC concentration [80, 143]. Hoppe et al [144] found a dose-response relationship between dietary BC and plasma, liver, and perirenal BC and hepatic VA concentrations, providing evidence that calves both absorb BC intact and convert it to VA. Kon et al [145] found that calves converted orally administered BC to VA in blood and liver, while an intravenous injection of BC did not result in increased VA.…”

“…Plasma BC also accumulated in plasma, lymphocytes, and neutrophils when dogs were dosed for up to 30 days with BC [175]. However, the plasma response to the BC dose was much lower in dogs compared to similar single dose studies in cats [177], ferrets [178], and calves [142, 143]. …”

The effects of LH on progesterone production by cell subpopulations isolated from early and late luteal phase goat corpora lutea

“…The cholesterol that arrives at the ovary via the blood stream is transported by either high-density lipoprotein (HDL) or low-density lipoprotein (LDL), depending on the animal species. LDL cholesterol accounts for the majority of blood cholesterol in pigs (12), whereas HDL cholesterol predominates in goats (13) and bovines (14).…”