Graham-Thiers P M, Kronfeld D S, Kline K A
Virginia Polytechnic Institute and State University, Blacksburg 24061-0606, USA.
Equine Vet J Suppl. 1999 Jul(30):463-7. doi: 10.1111/j.2042-3306.1999.tb05266.x.
Dietary protein during conditioning and exercise must support additional needs while avoiding adverse metabolic effects. Ten Arabian horses were assigned randomly to 2 diets formulated to contain 7.5 or 14.5% crude protein and 12% fat. The low-protein diet (LP) was supplemented with lysine and threonine to match the levels of these amino acids in the high-protein diet (HP). Feed intake averaged 8.1 kg/day. Dietary cation-anion difference was 181.6 and 260.4 mmol/kg for high and low protein, respectively. Following 9 weeks conditioning, horses performed a repeated sprint test: 3 min walk at 1.5 m/s and zero slope, followed by 3 min walk at 1.5 m/s, 5 min trot at 3.5 m/s, then six 1 min sprints at 10 m/s separated by 4 min walks all on a 6% slope, concluding with 30 min walk at 1.5 m/s and zero slope. Blood samples (arterial, A, and venous, V) were taken at rest, during the last 15 s of each sprint, and at 5, 10, 20 and 30 min. of recovery. Samples were analysed for total protein (TP), lactate (La-), pH, PCO2, PO2, HCO3-, Na+, K+ and Cl-. Strong ion difference (SID+) and total weak acids (Atot) were calculated. Analysis of variance with repeated measures was used to evaluate the effects of exercise and recovery (time), diet and any interactions. Comparing LP to HP groups, plasma pH tended to be higher after the first sprint (V, P = 0.084; A, P = 0.014), and plasma HCO3- was higher overall (V, P = 0.0023; A, P = 0.094) during exercise and recovery. In both groups, pH declined; however, LP remained higher than HP. The decline in pH represents an exercise-induced acidosis which was attributable mainly to PCO2, especially during recovery, and to a tendency for a higher SID+ during most of exercise and recovery. The plasma La- response was lower, Cl- higher, suggesting that LP enhanced the lactate-storage function of erythrocytes. Dietary protein restriction for 9 weeks moderated sprint-induced acidosis in fat-adapted horses.
在适应训练和运动期间，膳食蛋白质必须满足额外需求，同时避免产生不良代谢影响。将10匹阿拉伯马随机分配到两种日粮中，日粮配方中粗蛋白含量分别为7.5%或14.5%，脂肪含量为12%。低蛋白日粮（LP）补充了赖氨酸和苏氨酸，使其这些氨基酸水平与高蛋白日粮（HP）相匹配。平均采食量为8.1千克/天。高蛋白和低蛋白日粮的膳食阴阳离子差分别为181.6和260.4毫摩尔/千克。经过9周的适应训练后，马匹进行了重复短跑测试：以1.5米/秒的速度在零坡度下行走3分钟，然后以1.5米/秒的速度行走3分钟，以3.5米/秒的速度小跑5分钟，然后在6%的坡度上以10米/秒的速度进行六次1分钟的冲刺，每次冲刺间隔4分钟行走，最后以1.5米/秒的速度在零坡度下行走30分钟。在休息时、每次冲刺的最后15秒以及恢复的5、10、20和30分钟采集血样（动脉血，A，和静脉血，V）。分析血样中的总蛋白（TP）、乳酸（La-）、pH值、PCO2、PO2、HCO3-、Na+、K+和Cl-。计算强离子差（SID+）和总弱酸（Atot）。采用重复测量方差分析来评估运动和恢复（时间）、日粮以及任何相互作用的影响。比较LP组和HP组，第一次冲刺后血浆pH值有升高趋势（静脉血，P = 0.084；动脉血，P = 0.014），并且在运动和恢复期间血浆HCO3-总体上更高（静脉血，P = 0.0023；动脉血，P = 0.094）。在两组中，pH值均下降；然而，LP组仍高于HP组。pH值下降代表运动诱导的酸中毒，这主要归因于PCO2，尤其是在恢复期间，并且在大部分运动和恢复期间SID+有升高趋势。血浆La-反应较低，Cl-较高，表明LP增强了红细胞的乳酸储存功能。对适应高脂肪日粮的马匹进行9周的膳食蛋白质限制可减轻短跑诱导的酸中毒。
