Blood serotonin concentrations in phobic dogs fed a dissociated carbohydrate-based diet: A pilot study

Aim of this study was to evaluate the effects of a carbohydrate-based diet on serotonin blood concentrations in phobic dogs. For this study were recruited, from a public shelter, three dogs (2 neutered females and 1 male), weighing between 15 and 30 kg and living in the shelter for more than six months. Dogs received by a veterinary behaviorist a diagnosis of interspecific social phobia. The dogs were fed 2 daily meals (at 8.00 A.M. and 4.00 P.M.), the first meal was exclusively carbohydrate-based (puffed rice) whereas the second one was composed by the commercial diet. Blood was collected every 21 days after 8 hours from carbohydrate meal to determine the levels of serotonin (5-HT), L-tryptophan (TRP) and cortisol. Statistical analysis did not reveal any significative difference between the serum concentrations of 5-HT, TRP and cortisol, at the different times, despite a tendency to increase during the time. The results of this research are useful for directing further studies in the right direction, verifying the correctness of the hypotheses that can be formulated based on the analysis of these data. Blood concentrations of cortisol suggest that there have been no particular episodes of stress. For this reason, it is possible to exclude that the reduced transformation of TRP in 5-HT is due to an increased activity of tryptophan 2,3-dioxygenase induced by cortisol. In conclusion, these results are to be considered as a further step to address, more correctly, further research on the effect of diet manipulation on serotonin blood and brain concentrations.