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- Author or Editor: Gregory A. Reinhart x
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Abstract
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 dogs.
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: 609–615)
Abstract
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 damage.
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 r 2 = 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)
Abstract
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 2000;61:1438–1445)
Abstract
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)
