scholarly journals Exercise but Not Supplemental Dietary Tryptophan Influences Heart Rate and Respiratory Rate in Sled Dogs

2020 ◽  
Vol 7 (3) ◽  
pp. 97 ◽  
Author(s):  
Emma Thornton ◽  
James R. Templeman ◽  
Michael Bower ◽  
John P. Cant ◽  
Graham P. Holloway ◽  
...  

Tryptophan (Trp), an indispensable amino acid for dogs, is the precursor of serotonin, a neurotransmitter with a variety of effects throughout the body, including the ability to modulate cardiac and pulmonary activity. This study aimed to investigate the effects of a 12-week incremental exercise regimen and supplemental dietary Trp on heart rate (HR) and respiratory rate (RR) in client-owned sled dogs. Sixteen Siberian huskies were randomly allocated to either treatment or control diet groups. Both groups were fed a control diet (Trp to large neutral amino acid ratio of 0.047:1); however, treatment dogs received a Trp supplement to achieve a Trp to large neutral amino acid ratio of 0.075:1. Every three weeks, external telemetry equipment was used to non-invasively measure and record HR and RR at a resting, working, and post-exercise state in a controlled exercise challenge. A mixed model was used to test differences between diet, activity parameter, and week. Dietary Trp supplementation had no effect on HR or RR. Independent of diet, resting, working, post-exercise HR, and time to recover post-exercise HR decreased from week −1 to week 11 (p < 0.05). Resting HR had the greatest reduction from week −1 to week 11 (21%, p < 0.05). Working RR did not change with exercise (p > 0.10), but rRR and postRR decreased from week −1 to week 11 (p < 0.05). These data suggest that the exercise regimen the dogs were subjected to may have positively impacted the dogs’ capacity to sustain aerobic exercise, whereas Trp supplementation had no effect on HR or RR.

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 58-59
Author(s):  
Emma Thornton ◽  
James Templeman ◽  
Michael Bower ◽  
John Cant ◽  
Graham Holloway ◽  
...  

Abstract Repetitive bouts of resistance and aerobic exercise can have dramatic effects on whole body physiology. Dietary tryptophan supplementation supports protein turnover and serotonin production, which assist in responses to exercise. The objective of this study was to investigate the effects of a 12-week incremental exercise regimen and supplemental dietary tryptophan on pre-, mid-, and post-exercise heart rate and respiratory rate in sled dogs. Sixteen dogs (mean age of 4.8 ± 2.5 years, body weight 24.3 ± 4.3 kg) were blocked for sex, age, and body weight, and randomly allocated to a control diet or the control plus tryptophan diet (tryptophan to large-neutral-amino-acid ratio of 0.075:1). All dogs participated in a 12-week conditioning regimen with controlled exercise challenges at week -1 and subsequently every 3 weeks. Electrocardiogram electrodes and thoracic rib bands were worn to record heart rate and respiratory rate (EMKA Tech., Falls Church, VA, USA) prior to, during, and following each exercise challenge. A trans regression, mixed, and correlation model were used where appropriate to assess the fixed effects of treatment and week, and explore linear relationships between recovery time and week in SAS (v 9.4). No differences were found in heart rate between treatment groups for any training level (P &gt; 0.10). Working, recovery, and time required for heart rate to recover post-exercise decreased from week -1 to week 11 (P &lt; 0.05). Correlation analysis indicated that treatment dogs recovered respiratory rate faster post-exercise compared to control (r = -0.421, P &lt; 0.05). Resting, recovery and time required for respiratory rate to recover post-exercise decreased from baseline to week 11 (P &lt; 0.05). This data suggests improvement in cardiorespiratory fitness was observed over 12 weeks of training and that tryptophan may support respiratory function during exercise recovery.


Pharmacology ◽  
1991 ◽  
Vol 43 (4) ◽  
pp. 210-219 ◽  
Author(s):  
Thomas S. Burns ◽  
Wayne Stargel ◽  
Christian Tschanz ◽  
Frank N. Kotsonis ◽  
Aryeh Hurwitz

2020 ◽  
Vol 98 (5) ◽  
Author(s):  
James R Templeman ◽  
Emma Thornton ◽  
Cara Cargo-Froom ◽  
Eli J Squires ◽  
Kelly S Swanson ◽  
...  

Abstract 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 &lt; 0.05). Fecal data indicated that Trp improved stool scores (P &lt; 0.05) yet had no effect on fecal metabolites. An overall increase in lean and decrease in fat mass was found (P &lt; 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.


2007 ◽  
Vol 174 (1) ◽  
pp. 139-146 ◽  
Author(s):  
A. Douglas Wilson ◽  
Amanda J. Badnell-Waters ◽  
Rachel Bice ◽  
Ailison Kelland ◽  
Pat A. Harris ◽  
...  

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