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Kinetic behavior of three preparations of α-tocopherol after oral administration to postpubertal heifers

Valentino BontempoDepartment of Scienze Animali, Vegetali e dell'Ambiente, University of Molise, Via De Sanctis Contrada Vazzieri, 86100, Campobasso, Italy.

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Antonella BaldiInstitute of Animal Nutrition, Faculty of Veterinary Medicine, Via Celoria 10, 20133, Milan, Italy.

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Federica CheliInstitute of Animal Nutrition, Faculty of Veterinary Medicine, Via Celoria 10, 20133, Milan, Italy.

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Francesco FantuzInstitute of Animal Nutrition, Faculty of Veterinary Medicine, Via Celoria 10, 20133, Milan, Italy.

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 Dr Anim Prod Sc, PhD
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Ioannis PolitisDelta Dairy, 16 Leophorus Yrinis, 17778 Tavros, Athens, Greece.

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Silvano CarliInstitute of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, Via Celoria 10, 20133, Milan, Italy.

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Vittorio Dell'OrtoInstitute of Animal Nutrition, Faculty of Veterinary Medicine, Via Celoria 10, 20133, Milan, Italy.

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Abstract

Objective—To assess the kinetic behavior of 3 preparations of α-tocopherol (vitamin E) after oral administration to heifers.

Animals—8 postpubertal Friesian heifers.

Procedure—A single oral bolus of 5,000 U of α-tocopherol in oil or encapsulated in liposomes or cyclodextrin was administered to each cow, using a 4 X 4 design with 8 days between treatments. Blood samples for kinetic analyses were obtained at various times for 168 hours after treatment.

Results—Mean (± SEM) maximal plasma concentrations of α-tocopherol were 4.86 ± 0.49 µg/ml, 5.03 ± 0.39 µg/ml, and 5.08 ± 0.56 µg/ml after administration of oil, liposomal, and cyclodextrin preparations, respectively. Plasma concentrations peaked 21 to 34 hours after administration. The disappearance rate constant (Kd) was less after administration of α-tocopherol encapsulated in liposomes, compared with the other 2 preparations. Area under the concentration versus time curve was greater after administration of either encapsulated form of α-tocopherol, compared with α-tocopherol in oil, but these differences were not significant.

Conclusions and Clinical Relevance—The lower Kd determined for α-tocopherol encapsulated in liposomes suggests that this formulation may result in longer persistance of the vitamin in plasma than the other 2 preparations. Dietary supplementation with α-tocopherol encapsulated in liposomes may enhance plasma availability of this vitamin in cattle and could be useful during periods of increased vitamin E requirements, such as parturition and early stages of life. (Am J Vet Res 2000;61:589–593)

Abstract

Objective—To assess the kinetic behavior of 3 preparations of α-tocopherol (vitamin E) after oral administration to heifers.

Animals—8 postpubertal Friesian heifers.

Procedure—A single oral bolus of 5,000 U of α-tocopherol in oil or encapsulated in liposomes or cyclodextrin was administered to each cow, using a 4 X 4 design with 8 days between treatments. Blood samples for kinetic analyses were obtained at various times for 168 hours after treatment.

Results—Mean (± SEM) maximal plasma concentrations of α-tocopherol were 4.86 ± 0.49 µg/ml, 5.03 ± 0.39 µg/ml, and 5.08 ± 0.56 µg/ml after administration of oil, liposomal, and cyclodextrin preparations, respectively. Plasma concentrations peaked 21 to 34 hours after administration. The disappearance rate constant (Kd) was less after administration of α-tocopherol encapsulated in liposomes, compared with the other 2 preparations. Area under the concentration versus time curve was greater after administration of either encapsulated form of α-tocopherol, compared with α-tocopherol in oil, but these differences were not significant.

Conclusions and Clinical Relevance—The lower Kd determined for α-tocopherol encapsulated in liposomes suggests that this formulation may result in longer persistance of the vitamin in plasma than the other 2 preparations. Dietary supplementation with α-tocopherol encapsulated in liposomes may enhance plasma availability of this vitamin in cattle and could be useful during periods of increased vitamin E requirements, such as parturition and early stages of life. (Am J Vet Res 2000;61:589–593)