Research Article: Benefits of dietary supplements on the physical fitness of German Shepherd dogs during a drug detection training course

Date Published: June 14, 2019

Publisher: Public Library of Science

Author(s): Laura Menchetti, Gabriella Guelfi, Roberto Speranza, Pasquale Carotenuto, Livia Moscati, Silvana Diverio, Juan J Loor.


A high standard of physical fitness is an essential characteristic of drug detection dogs because it affects not only their ability to sustain high activity levels but also their attention and olfaction efficiency. Nutritional supplements could improve physical fitness by modulating energy metabolism, oxidative processes, and perceived fatigue. The aim of this study was to investigate the physiological and biochemical changes induced by submaximal exercise on drug detection dogs (German Shepherd breed) and to assess whether a dietary supplement improves their physical fitness. During a drug detection dog training course, seven dogs were fed with a basal diet (Control Group) for three-month period, while a further seven dogs were fed with a basal diet as well as a daily nutritional supplement containing branched-chain and limiting amino acids, carnitine, vitamins, and octacosanol (Treatment Group). At the end of this period, individual physical fitness was assessed by making each subject take a graded treadmill exercise test. A human heart rate monitor system was used to record the dog’s heart rate (HR) during the treadmill exercise and the subsequent recovery period. The parameters related to HR were analysed using nonparametric statistics. Blood samples were collected before starting the nutritional supplement treatment, before and after the treadmill exercise and following recovery. Linear mixed models were used. The dietary supplements accelerated HR recovery, as demonstrated by the lower HR after recovery (P<0.05) and Time constants of HR decay (P<0.05), and by the higher Absolute HR Recovered (P<0.05) recorded in the Treatment group compared with the Control dogs. The supplemented dogs showed the lowest concentrations of creatine kinase (CK; P<0.001), aspartate aminotransferase (AST, P<0.05) and non-esterified fatty acids (NEFA; P<0.01) suggesting a reduction in muscle damage and improvement of energy metabolism. These data suggest that this combined supplement can significantly enhance the physical fitness of drug detection dogs.

Partial Text

Since ancient times, working dogs have been considered as extremely accurate and flexible extensions of mankind’s senses and capabilities. Despite modern technological advancements, machines fail to match the competence of dogs trained for a range of tasks, i.e. for detecting explosives and narcotics or searching for missing people and avalanche victims [1–5]. For this reason, drug detection dogs are used by law-enforcement authorities all over the world [6].

The experimental protocol of the study was approved by the Ethical Committee of the University of Perugia protocol number: n. 2018–21 and complies with the laws established by the Italian Ministry of Health. There is a standing agreement between the Italian Military Force of GdF and the Department of Veterinary Medicine of Perugia University for the ethical testing and study of GdF working dogs.

Drug detection dogs must have good olfactory detection capabilities and behavioural traits and also need to be physically fit. Indeed, excessive physical exertion may affect concentration, olfactory capability, search duration and the performance of working dogs [8].

The supplement containing branched-chain and limiting amino acids, carnitine, vitamins, and octacosanol proved effective in improving the physical fitness of drug detection dogs by exerting beneficial effects on HR recovery, energy metabolism and biomarkers of muscle damage. The findings have important management applications and encourage the routine use of nutritional supplements in the feeding regime of working dogs.




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