Astaxanthin uptake in domestic dogs and cats.

Background: Research on the uptake and transport of astaxanthin is lacking 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; 3 to 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 mumol/L in both species, and was observed at 6 h post-dosing. The plasma astaxanthin elimination half-life was 9 to 18 h. 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 high density 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 subcellular organelles. Certain aspects of the biokinetic uptake of astaxanthin in dogs and cats are similar to that in humans.