Exercise improves the health of dogs; however, the extreme exertion experienced by sled dogs may lead to variable metabolic and fecal characteristics. Nutritional interventions, such as dietary tryptophan (Trp), may reduce the prevalence of these exercise-induced disturbances. Sporting diets tend to have high crude protein concentrations in contrast to adult maintenance diets and this results in less Trp relative to other amino acids (AA). Therefore, sporting dogs represent an ideal cohort to assess the effects of supplemental Trp. The objective was to evaluate the effects of supplemental dietary Trp and an incremental training regimen on AA and serotonin status, fecal scores and metabolites, and body composition in client-owned Siberian huskies. Sixteen dogs (nine females and seven males) were used, with a mean age of 4.8 ± 2.5 yr and body weight (BW) of 24.3 ± 4.3 kg. Dogs were blocked for sex, age, and BW and randomly allocated into two groups with eight fed a dry extruded control diet (Ctl) and eight fed Ctl supplemented with Trp to reach a Trp:large-neutral AA (LNAA) ratio of 0.075:1 (treatment, Trt). The exercise regimen was designed to increase in distance each week, but weather played a role in setting the daily distance. Each week BW was recorded and food allotments were adjusted to maintain initial BW. Pre and post-exercise blood samples were taken every 3 wk, dogs then received a meal followed by 1, 2, and 4 h post meal blood collections (serum AA, serotonin). Stool collection and scoring occurred each week and body composition was measured on weeks -1 and 11. Serotonin, AA, fecal metabolite, and body composition data were analyzed using PROC MIXED of SAS with dog as a random effect and week and Trt as fixed effects. Stool score data were analyzed using PROC FREQ to compare stool score and Trt, and PROC CORR was used to analyze associations between fecal score, temperature, humidity, and run distance. Dogs on Trt had greater fasted Trp compared with baseline, greater post-meal Trp and serotonin compared with baseline, greater post-meal Trp compared with fasted, and greater post-meal Trp and serotonin compared with Ctl (P < 0.05). Fecal data indicated that Trp improved stool scores (P < 0.05) yet had no effect on fecal metabolites. An overall increase in lean and decrease in fat mass was found (P < 0.05), but Trt had no effect on body composition. Optimization of the dietary Trp:LNAA ratio may help to improve GI health without compromising performance in actively training sled dogs.

中文翻译：

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补充运动和饮食色氨酸补充对中距离训练雪橇犬氨基酸代谢，血清素状态，粪便质量，粪便代谢产物和身体成分的影响。

运动可以改善狗的健康；但是，雪橇犬的过度劳累可能会导致新陈代谢和粪便特性变化。营养干预措施，例如饮食中的色氨酸（Trp），可能会减少这些运动引起的不适的患病率。与成人维持饮食相比，运动饮食往往具有较高的粗蛋白浓度，因此相对于其他氨基酸（AA）而言，其Trp更少。因此，运动犬代表了评估补充色氨酸的作用的理想人群。目的是评估补充饮食的Trp和递增训练方案对客户拥有的西伯利亚哈士奇犬的AA和5-羟色胺状态，粪便评分和代谢产物以及身体成分的影响。使用了十六只狗（九只雌性和七只雄性），平均年龄为4.8±2。5年，体重（BW）为24.3±4.3公斤。将犬按性别，年龄和体重进行分组，随机分为两组，其中八组喂饲干挤压对照饮食（Ctl），八组喂食补充了Trp的Ctl，达到0.075：的Trp：大中性AA（LNAA）比。 1（治疗，Trt）。运动方案的设计是每周增加一次距离，但天气在设定每日距离方面起着一定作用。每周记录体重，并调整食物分配以维持初始体重。运动前和运动后每3周采集一次血液样本，然后给狗进餐，然后在进餐后1、2和4小时采血（血清AA，血清素）。每周进行粪便收集和计分，并在第-1和11周测量身体成分。5-羟色胺，AA，粪便代谢物，使用SAS的PROC MIXED分析狗的身体成分数据，以狗为随机效应，以周和Trt为固定效应。使用PROC FREQ分析粪便评分数据，以比较粪便评分和Trt，PROC CORR用于分析粪便评分，温度，湿度和跑步距离之间的关联。与基线相比，接受Trt的狗的禁食Trp更高，与基线相比，餐后的Trp和血清素的含量更高，与禁食相比，餐后的Trp和血清素的含量高于Ctl（P <0.05）。粪便数据表明，Trp改善了粪便评分（P <0.05），但对粪便代谢产物没有影响。发现瘦肉总体增加而脂肪量减少（P <0.05），但是Trt对身体成分没有影响。膳食Trp的优化：