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- Author or Editor: Arleigh J. Reynolds x
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Abstract
Objective
To determine effects of protein intake on blood variables, plasma volume, and maximal oxygen uptake (Vo2max) in sled dogs undergoing rigorous training.
Animals
32 Alaskan sled dogs, between 2 and 6 years old.
Procedure
Dogs were assigned to 1 of 4 groups on the basis of age, sex, and ability. Isocaloric diets containing 18% (diet A), 23% (diet B), 29% (diet C), or 35% (diet D) of energy as protein were assigned randomly to each group and fed 1 month before and during a 12-week training period. Maximal oxygen uptake was measured at 0 (before training) and 12 weeks. Body weight, protein and energy intake, plasma volume, PCV, hemoglobin concentration, and serum biochemical variables were measured at 0, 8, and 12 weeks.
Results
Serum biochemical variables, PCV, and hemoglobin concentration remained within reference ranges for all dogs. Dogs fed diet A had a decrease in Vo2max and a greater rate of soft tissue injury throughout training, compared with dogs fed the other diets. At 12 weeks, dogs fed diets C and D had greater serum sodium concentration and hemoglobin concentration than did dogs fed diet A. Dogs fed diet D also had more plasma volume at 12 weeks than did dogs of any other group.
Conclusions and Clinical Relevance
Consumption of a diet with 18% dietary protein on an energy basis (3.0 g of protein/kg of body weight) is insufficient to meet the metabolic requirements of sled dogs in training. For intense interval work, a diet with 35% dietary protein as energy (6.0 g of protein/kg) may provide a performance advantage by promoting an increase in plasma volume. (Am J Vet Res 1999;60: 789–795)
Abstract
OBJECTIVE To characterize the postprandial nutrient profiles of exercise-conditioned dogs fed a supplemental carbohydrate and protein bar with or without astaxanthin from Haematococcus pluvialis immediately after exercise.
ANIMALS 34 exercise-conditioned adult Husky-Pointer dogs.
PROCEDURES The study had 2 phases. During phase 1, postprandial plasma glucose concentration was determined for dogs fed a bar containing 25% protein and 18.5% or 37.4% maltodextrin plus dextrin (rapidly digestible carbohydrate; RDC), or dry kibble (30% protein and 0% RDC) immediately after exercise. During phase 2, dogs were exercised for 3 days and fed a bar (25% protein and 37.4% RDC) with (CPA; n = 8) or without (CP; 8) astaxanthin or no bar (control; 8) immediately after exercise. Pre- and postexercise concentrations of plasma biochemical analytes and serum amino acids were determined on days 1 and 3.
RESULTS Phase 1 postexercise glucose concentration was increased when dogs were provided the 37.4% RDC bar, but not 0% or 18.5% RDC. On day 3 of phase 2, the CPA group had the highest pre-exercise triglyceride concentration and significantly less decline in postexercise glucose concentration than did the CP and control groups. Mean glucose concentration for the CP and CPA groups was significantly higher than that for the control group between 15 and 60 minutes after bar consumption. Compared to immediately after exercise, branched-chain amino acid, tryptophan, leucine, and threonine concentrations 15 minutes after exercise were significantly higher for the CP and CPA groups, but were lower for the control group.
CONCLUSIONS AND CLINICAL RELEVANCE Dogs fed a bar with 37.4% RDCs and 25% protein immediately after exercise had increased blood nutrient concentrations for glycogen and protein synthesis, compared with control dogs.
SUMMARY
The size and quality of muscle specimens obtained by use of a percutaneous biopsy technique were studied. All biopsies were performed under local anesthesia, using an 11-gauge biopsy needle. The mean ± sem size of specimens obtained from 128 biopsies of the semitendinosus muscles of 16 Alaskan Huskies was 23.8 ± 4.4 mg. All biopsy specimens were of sufficient quality to permit histochemical differentiation of the fiber types by use of myosin ATPase staining. An additional 8 biopsy specimens were obtained from 1 dog and analyzed for muscle glycogen content. These specimens contained 50.6 ± 7.2 mmol of glucose/kg of muscle wet weight. This modified biopsy procedure was free of notable complications, and repeatable use produced specimens of adequate size and quality for histologic and biochemical analysis. It is concluded that this procedure is a safe and reliable alternative to open biopsy for diagnosis and management of neuromuscular, metabolic, and nutritional myopathies.
Abstract
Objective—To determine nitrogen balance in clinically normal dogs receiving parenteral nutrition solutions.
Animals—8 clinically normal female Beagles.
Procedure—Dogs were randomly assigned to receive 4 treatments in random order. Treatment A consisted of IV administration of nonlactated Ringer's solution. Treatments B, C, and D consisted of IV administration of isocaloric parenteral solutions containing 0, 1.36, and 2.04 g of amino acids/kg of body weight/d, respectively, for 7 consecutive days. Urine and feces were collected on days 5, 6, and 7 of each treatment period, and Kjeldahl analysis was used to determine nitrogen balance.
Results—Mean nitrogen balance was negative with treatments A and B but was not significantly different from 0 with treatments C and D. Dogs had the lowest nitrogen balance values and lost the most weight while receiving treatment A. Dogs were able to conserve protein and had higher nitrogen balance values when receiving treatment B, compared with treatment A. Dogs lost the least amount of weight while receiving treatment D. Regression analysis indicated that an IV amino acid intake of 2.32 g/kg/d (95% confidence interval, 2.00 to 2.81 g/kg/d), as supplied by the commercial product used in this study, would result in zero nitrogen balance in clinically normal dogs.
Conclusions and Clinical Relevance—Results suggest that IV amino acid requirement of clinically normal dogs is approximately 2.3 g/kg/d. ( Am J Vet Res 2001;62:912–920)
Objective
To determine whether feeding a low-carbohydrate, high-fat diet would decrease severity of exercise-induced muscle injury in horses with exertional rhabdomyolysis.
Animals
19 horses with a history of exertional rhabdomyolysis.
Design
Case series.
Procedure
Specimens of the semitendinosus or semimembranosus muscle were obtained for histologic examination, and serum creatine kinase (CK) and aspartate transaminase (AST) activities 4 hours after exercise were determined. Horses were then fed a low-carbohydrate, high-fat diet, and serum CK and AST activities 4 hours after exercise were reevaluated at approximately monthly intervals for 3 to 6 months.
Results
Serum CK and AST activities 4 hours after exercise were high before any change in diet. All 19 horses had evidence of chronic myopathic change and abnormal glycogen accumulation in muscle biopsy specimens; 11 horses also had evidence of complex polysaccharide accumulation. Adaptation to diet change required approximately 3 to 6 months. Sixteen horses did not have any episodes of exertional rhabdomyolysis after 3 to 6 months of diet change, and 3 horses had mild episodes of exertional rhabdomyolysis following either a reduction in dietary fat intake or restriction in exercise. Postexercise serum CK and AST activities 3 to 6 months after the change in diet were significantly less than initial values.
Clinical Implications
Results indicated that exertional rhabdomyolysis may be a result of abnormal carbohydrate metabolism in some horses. Feeding a diet with low carbohydrate and high fat content may reduce severity of exercise-induced injury in some horses with exertional rhabdomyolysis. (J Am Vet Med Assoc 1998;212:1588–1593).