A Four-Week Urban Diet Impairs Vasodilation but Not Nutritional Physiology in Wild-Caught Mourning Doves (Zenaida macroura)

Birds living in urban areas routinely consume anthropogenic foods, but the physiological consequences of this consumption are poorly understood. To address this question, we investigated the effects of an urban diet (UD) in wild, urban-caught mourning doves in a controlled environment. Since anthropogenic foods often contain a high proportion of refined carbohydrate and fat, we predicted that UD consumption alters body mass as well as plasma and tissue metabolites and that it impairs vasodilation. To test this prediction, we compared body mass, various nutritional physiology parameters, and peripheral vasodilation of doves fed an UD (1:1 ratio of bird seeds and french fries; n=6) with those of doves receiving a control diet (CON, bird seed diet; n=7) for 4 wk. At the end of the dietary manipulation period, birds were euthanized, and we dissected cranial tibial arteries to measure ex vivo vasodilation in response to acetylcholine treatment after phenylephrine-induced vasoconstriction. We also collected cardiac blood as well as liver, pectoralis, and gastrocnemius muscle samples to measure nutritional metabolite concentrations. Vasodilation of tibial arteries was impaired in UD- compared to CON-fed birds (P=0.004), suggesting the potential for UD consumption to alter cardiovascular function. Body mass, plasma osmolality, glucose, sodium, insulin, triglyceride, uric acid, liver glycogen and triglycerides, and muscle glycogen did not differ between groups. The results suggest that short-term consumption of a diet composed of 50% anthropogenic foods is not associated with major metabolic perturbations in urban mourning doves.