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)
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