Objective—To compare fermentation characteristics
of fructooligosaccharides (FOS) and other fiber substrates
that are commonly found in canine diets.
Sample Population—Fecal samples from 3 adult
Procedure—The ability of fiber substrates to be used
in microbial fermentation reactions was assessed by
use of an in vitro fermentation system. Dogs were fed
a commercially available food, and feces were collected
for use as the microbial inoculum. Substrates
used were beet pulp, cellulose, soy fiber, mannanoligosaccharides
(MOS), FOS, and 4 inulin products
(inulin 1, 2, 3, and 4). Each substrate was incubated
anaerobically with fecal inoculum and growth media
for 6, 12, and 24 hours, and production of short-chain
fatty acids (SCFA) was measured.
Results—Total production of SCFA was higher for fermentation
of the 4 inulin products and FOS, whereas
fermentation of beet pulp, MOS, and soy fiber resulted
in moderate concentrations of SCFA. Fermentation
of cellulose produced the lowest concentrations
of total SCFA without detection of butyrate or
lactate. Butyrate production was greatest for fermentation
of the 4 inulin products and FOS. Total lactate
production was greatest for FOS and inulin 4. As
expected, production of SCFA increased for all substrates
as fermentation time increased.
Conclusion and Clinical Relevance—Canine fecal
microflora ferment FOS-containing substrates in a
similar manner, with little fermentation of cellulosebased
carbohydrates. Furthermore, results of an in
vitro fermentation system indicate that fiber type
affects the metabolic activity of microorganisms, thus
influencing the amount and nature of the end products
of fermentation. (Am J Vet Res 2001;62:
Objective—To determine whether repetitive endurance
exercise in sled dogs was associated with
substantial lipid peroxidation, decreases in antioxidant
capacity of the serum, and skeletal muscle
Animals—24 lightly trained sled dogs.
Procedure—16 dogs completed a 58-km run on each
of 3 consecutive days; the other 8 dogs
(control) did not exercise during the study. Blood samples
were collected before the first exercise run and
after the first and third exercise runs. Plasma isoprostane
and serum vitamin E concentrations, total
antioxidant status of plasma, and serum creatine
kinase activity were measured.
Results—Plasma isoprostane concentrations in dogs
in the exercise group were significantly increased
after the first exercise run and further significantly
increased after the third exercise run. Serum vitamin
E concentration was significantly decreased after the
first exercise run in dogs in the exercise group, and
this change persisted after the third exercise run.
There was a significant linear relationship between
plasma isoprostane concentration and the logarithm
of serum creatine kinase activity (adjusted r2 = 0.84).
Conclusions and Clinical Relevance—Results
demonstrate that repetitive endurance exercise in
dogs is associated with lipid peroxidation and a reduction
in plasma antioxidant concentrations. We interpret
these results as indicating that the antioxidant
mechanisms of minimally trained dogs may, in some
instances, be inadequate to meet the antioxidant
requirements of repetitive endurance exercise. (Am J Vet Res 2000;61:512–517)
Objective—To determine whether dietary antioxidants
would attenuate exercise-induced increases in
plasma creatine kinase (CK) activity in sled dogs.
Animals—41 trained adult sled dogs.
Procedure—Dogs, randomly assigned to 2 groups,
received the same base diet throughout the study.
After 8 weeks on that diet, 1 group (21 dogs) received
a daily supplement containing vitamins E (457 U) and
C (706 mg) and β-carotene (5.1 mg), and a control
group (20 dogs) received a supplement containing
minimal amounts of antioxidants. After 3 weeks, both
groups performed identical endurance exercise on
each of 3 days. Blood samples were collected before
and 3 weeks after addition of supplements and after
each day of exercise. Plasma was analyzed for vitamins
E and C, retinol, uric acid, triglyceride, and cholesterol
concentrations, total antioxidant status (TAS),
and CK activity.
Results—Feeding supplements containing antioxidants
caused a significant increase in vitamin E concentration
but did not change retinol or vitamin C concentrations
or TAS. Exercise caused significantly higher
CK activity, but did not cause a significant difference
in CK activity between groups. Exercise was
associated with significantly lower vitamin E, retinol,
and cholesterol concentrations and TAS but significantly
higher vitamin C, triglyceride, and uric acid concentrations
in both groups.
Conclusions and Clinical Relevance—Use of supplements
containing the doses of antioxidants used
here failed to attenuate exercise-induced increases in
CK activity. Muscle damage in sled dogs, as measured
by plasma CK activity, may be caused by a
mechanism other than oxidant stress. (Am J Vet Res
Objective—To study the musculoskeletal development
of Great Dane puppies fed various dietary concentrations
of calcium (Ca) and phosphorus (P) in
fixed ratio by use of dual energy x-ray absorptiometry
(DEXA), determination of serum insulin-like growth
factor I and parathyroid hormone concentrations,
radiography, and blood chemistry analysis results.
Animals—32 purebred Great Dane puppies from 4 litters.
Procedure—At weaning, puppies were assigned randomly
to 1 of 3 diets. Blood was collected for biochemical
analyses and hormone assays, and radiography
and DEXA were performed through 18 months of
age. Changes in body weight, bone mineral content, fat
tissue weight, lean mass, result of serum biochemical
analyses, hormonal concentrations, and radius lengths
were analyzed through 18 months of age.
Results—Bone mineral content of puppies correlated
positively with Ca and P content of the diets fed.
Significant differences between groups in bone mineral
content, lean mass, and body fat were apparent
early. The disparity among groups increased until 6
months of age and then declined until body composition
was no longer different at 12 months of age.
Accretion rates for skeletal mineral content, fat, and
lean tissue differed from each other and by diet group.
Conclusions and Clinical Relevance—Ca and P concentrations
in the diet of young Great Dane puppies
are rapidly reflected in the bone mineral content of
the puppies until 5 to 6 months of age, after which
hormonal regulation adjusts absorption and excretion
of these minerals. Appropriate Ca and P concentrations
in diets are important in young puppies < 6
months of age. (Am J Vet Res 2002;63:1036–1047)