Hammel E P, Kronfeld D S, Ganjam V K, Dunlap H L
Am J Clin Nutr. 1977 Mar;30(3):409-18. doi: 10.1093/ajcn/30.3.409.
Eighteen racing sled dogs were assigned to three diets containing protein, fat, and carbohydrate in proportions as follows: diet A, 39:61:0; diet B, 32:45:23; and diet C, 28:34:38 on an available energy basis. The dogs were studied through a 28-week training period and subjected to three special tests, the first after 12 weeks training, the second at 24 weeks, and the third 4 weeks later. Overnight fasting, resting blood samples were taken before exercise, then about 5 or 30 min after exercise in the first 2 tests, or 1,5...30 min after exercise in the third test. Negligible changes in the red cell indices or serum concentrations of total protein, sodium, and urea indicated that there were no major water shifts. Significant decrements were found in serum concentrations of albumin (3% of resting value), calcium (4%), magnesium (13%), and inorganic phosphorus (39%). Significant increments were found in serum concentrations of creatinine (50%) and activities of glutamic-pyruvic and glutamic-oxalacetic transaminases (31 and 52%, respectively). None of the above variables showed differences between diets, exercise bouts, or time after exercise. Significant decrements in plasma cholesterol (D, mg/100 ml) were linearly related to the initial concentration (I mg/100 ml); D - 0.161 I - 17 mg/100 ml. Hyperglycemic responses were exhibited by 14 dogs in the 3rd test, including five dogs on diet A. Resting plasma glucose concentrations, peak values after exercise, and removal rates were the same in dogs fed all three diets. Blood lactic acid concentrations were linearly related to plasma glance (two from each group) had significantly higher peak lactic/glucose ratios tthan the six "worst" dogs, but there was no significant difference between diets in other measures of glucose or lactic acid. Plasma concentrations of free fatty acids, acetoacetic acid and 3-OH-butyric acid reached a maximum 10 min after exercise. Peak values and mean increments of free fatty acids were highest in dogs fed diet A. Also, mean free fatty acid increment was significantly higher in the six best dogs than in the six worst. An enhanced ability to mobilize body fat should confer an advantage in a dog subjected to prolonged strenous exercise in which fatty acid oxidation accounts for most of the oxygen consumption.
18只赛犬被分配到三种饮食组，三种饮食中蛋白质、脂肪和碳水化合物的比例如下：按可利用能量计算，饮食A为39:61:0；饮食B为32:45:23；饮食C为28:34:38。这些犬在28周的训练期内接受研究，并进行三项特殊测试，第一次在训练12周后，第二次在24周时，第三次在4周后。在运动前采集过夜禁食后的静息血样，然后在第一次和第二次测试中运动后约5或30分钟采集，或在第三次测试中运动后1、5……30分钟采集。红细胞指数或血清总蛋白、钠和尿素浓度的变化可忽略不计，表明没有重大的水分转移。血清白蛋白浓度（降至静息值的3%）、钙（4%）、镁（13%）和无机磷（39%）显著下降。血清肌酐浓度（升高50%）以及谷丙转氨酶和谷草转氨酶活性（分别升高31%和52%）显著升高。上述变量在不同饮食、运动回合或运动后时间之间均未显示出差异。血浆胆固醇的显著下降（D，mg/100 ml）与初始浓度（I，mg/100 ml）呈线性相关；D = 0.161I - 17 mg/100 ml。在第三次测试中，14只犬出现高血糖反应，其中包括5只饮食A组的犬。喂食所有三种饮食的犬的静息血浆葡萄糖浓度、运动后的峰值以及清除率相同。血乳酸浓度与血浆葡萄糖呈线性相关（每组两只）的犬的乳酸/葡萄糖峰值比明显高于六只“最差”的犬，但在葡萄糖或乳酸的其他测量指标上，不同饮食之间没有显著差异。游离脂肪酸、乙酰乙酸和3-羟基丁酸的血浆浓度在运动后10分钟达到最高值。饮食A组的犬游离脂肪酸的峰值和平均增加值最高。此外，六只最佳犬的游离脂肪酸平均增加值明显高于六只最差犬。在长时间剧烈运动中，脂肪酸氧化占大部分耗氧量的情况下，增强的身体脂肪动员能力应会赋予犬一定优势。
