Astaxanthin uptake in domestic dogs and cats
Jean Soon Park1, Hong Wook Kim1, Bridget D Mathison1, Michael G Hayek2, Stefan Massimino2, Gregory A Reinhart2 and Boon P Chew*1
Abstract Background: Research on the uptake and transport of astaxanthin islacking in most species. We studied the uptake of astaxanthin by plasma, lipoproteins and leukocytes in domestic dogs and cats. Methods: Mature female Beagle dogs (18 to 19 mo old; 11 to 14 kg BW) were dosed orally with 0, 0.1, 0.5, 2.5, 10 or 40 mg astaxanthin and blood taken at 0, 3, 6, 9, 12, 18 and 24 h post-administration (n = 8/treatment). Similarly, mature domestic short hair cats (12 mo old; 3to 3.5 kg body weight) were fed a single dose of 0, 0.02, 0.08, 0.4, 2, 5, or 10 mg astaxanthin and blood taken (n = 8/treatment) at the same interval. Results: Both dogs and cats showed similar biokinetic profiles. Maximal astaxanthin concentration in plasma was approximately 0.14 μmol/L in both species, and was observed at 6 h post-dosing. The plasma astaxanthin elimination half-life was 9 to 18h. Astaxanthin was still detectable by 24 h in both species. In a subsequent study, dogs and cats were fed similar doses of astaxanthin daily for 15 to 16 d and astaxanthin uptake by plasma, lipoproteins, and leukocytes studied. In both species, plasma astaxanthin concentrations generally continued to increase through d 15 or 16 of supplementation. The astaxanthin was mainly associated with highdensity lipoprotein (HDL). In blood leukocytes, approximately half of the total astaxanthin was found in the mitochondria, with significant amounts also associated with the microsomes and nuclei. Conclusion: Dogs and cats absorb astaxanthin from the diet. In the blood, the astaxanthin is mainly associated with HDL, and is taken up by blood leukocytes, where it is distributed to all subcellularorganelles. Certain aspects of the biokinetic uptake of astaxanthin in dogs and cats are similar to that in humans. Introduction Research has shown that carotenoids play important roles in modulating immunity , reproduction , cancer , age-related macular degeneration, and atherosclerosis . However, these studies have focused mainly on β-carotene, lutein and lycopene. Recent studies havesimilarly shown that astaxanthin, a ketocarotenoid, possesses important biological actions . The antioxidant activity of astaxanthin has been reported to be higher than that of α-carotene, β-carotene and lutein [5,6] and α-tocopherol . Astaxanthin reduced oil-induced oxidative stress  and lowered serum lipid peroxides and transaminase activities  in fish. Both in vitro and in vivostudies have shown that astaxanthin can enhance humoral  and cell-mediated  immune responses, and inhibit cancer [12,13], and suppress bacterial infection . In spite of
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these known functions of astaxanthin, little is known concerning its uptake in most species. Our immediate objective is to study the biokinetic uptake of astaxanthin by blood,lipoproteins and leukocytes in dogs and cats; our long-term objective is to study the action of dietary astaxanthin in modulating immune health in these species.
Materials and Methods The comparative uptake of dietary astaxanthin in domestic dogs and cats was studied. All studies were approved by the Washington State University Institutional Animal Care and Use Committee.
School of FoodScience, Washington State University, Pullman, WA 991646376, USA
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Female Beagle dogs (18 to 19 mo old, 11 to 14 kg BW) were fed a nutritionally-balanced diet (200 g/dog/d, The Iams Co., Lewisburg, OH). The diet composition was as follows (g/kg): 66.2 moisture, 262 protein, 74.5 ash, 160 fat, 14.8 Ca, 10.3 P, and 437.3...