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  • Author or Editor: Boon P. Chew x
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Objectives—To determine uptake of β-carotene by ovarian and uterine tissues and influence of dietary β- carotene on steroidogenesis and production of uterine protein during the estrous cycle in cats.

Animals—56 female cats.

Procedure—Cats were fed diets containing 0, 0.4, 2, or 10 mg of β-carotene daily for 8 weeks prior to detection of estrus. At time of observed estrus, all cats were manually induced to ovulate. Blood samples were obtained at estrus and every 2 days until day 14 after ovulation. On that day, cats underment laparotomy, and the ovaries and uterus were removed. Uterine contents were flushed, and luteal and endometrial tissues were obtained.

Results—Concentrations of β-carotene in plasma and luteal and endometrial tissues increased in a dosedependent manner. Concentrations of plasma progesterone were higher between days 6 and 10 after ovulation in cats fed diets containing β-carotene and continued to increase through day 14 after ovulation in cats fed a diet containing 10 mg of β-carotene. Plasma concentration of estradiol-17β also was higher between days 0 and 4 after ovulation in cats fed diets containing β-carotene. Cats fed a diet containing 10 mg of β-carotene had the highest plasma estradiol concentration. Total uterine protein concentration was higher in cats fed β-carotene, compared with values for cats fed an unsupplemented diet.

Conclusion and Clinical Relevance—Cats readily absorb β-carotene. Increased concentrations of progesterone, estradiol, and uterine protein may provide more optimal ovarian function or a better uterine environment for embryonic survival and development. (Am J Vet Res 2001;62:1063–1067)

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in American Journal of Veterinary Research


Objectives—To determine effects of dietary antioxidant supplementation on plasma concentrations of antioxidants, exercise-induced oxidative damage, and resistance to oxidative damage during exercise in Alaskan sled dogs.

Animals—62 Alaskan sled dogs.

Procedure—Dogs were matched for age, sex, and ability and assigned to 1 of 3 groups: sedentary and nonsupplemented (control [C]; n = 21), exercised and supplemented (S; 22), and exercised and nonsupplemented (N; 19). Dogs in group S were given 400 units of α- tocopherol acetate, 3 mg of β-carotene, and 20 mg of lutein orally per day for 1 month, then dogs in groups S and N completed 3 days of exercise. Blood samples were collected before and after 1 and 3 days of exercise and after 3 days of rest. Plasma antioxidant concentrations were determined, and oxidative damage to DNA (plasma 7,8 dihydro-8-oxo-2'deoxyguanosine [8-oxodG] concentration) and membrane lipids (plasma hydroperoxide concentration) and resistance of plasma lipoproteins to oxidation were assessed.

Results—Supplementation increased plasma concentrations of α-tocopherol, β-carotene, and lutein. Plasma concentration of α-tocopherol increased and concentration of lutein decreased in group S with exercise. Concentration of 8-oxodG decreased in group S but increased in group N during and after exercise. Lag time of in vitro oxidation of lipoprotein particles increased with exercise in group S only.

Conclusions and Clinical Relevance—Dietary supplementation with antioxidants resulted in increased plasma concentrations of antioxidants. Moreover, supplementation decreased DNA oxidation and increased resistance of lipoprotein particles to in vitro oxidation. Antioxidant supplementation of sled dogs may attenuate exercise-induced oxidative damage. (Am J Vet Res 2000;61:886–891)

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in American Journal of Veterinary Research