Consumption of a Refined Carbohydrate Diet Does Not Impair Vasodilation of Cranial Tibial Arteries in the Mourning Dove, Zenaida macroura

Abstract

Chronic hyperglycemia in mammals correlates positively with the production of reactive oxygen species (ROS) and is associated with impaired vasodilation. Plasma glucose (Pglu) in birds including Mourning Doves (MODO) is generally higher than in mammals, yet vascular ROS in MODO are similar to levels measured in healthy rodents. This difference may be due to abundant endogenous antioxidants such as uric acid and vitamin C in birds. We hypothesized that feeding doves a refined carbohydrate diet would not impair vasodilation. To examine this, we captured MODO (n = 11) in Tempe, AZ, and housed them for five weeks. Birds were acclimated for one week during which they transitioned either to a nutritionally‐balanced dove seed diet (controls, CONT) or to a refined carbohydrate (WB; white sandwich bread) diet. We collected a blood sample from the brachial vein of each bird upon arrival and at the end of the 4‐week treatment for the measurement of serum metabolites. At the end of the study, we euthanized birds and cranial tibial arteries were isolated, cannulated with glass pipettes, and pressurized in a vessel chamber. Isolated arteries were pre‐constricted to 50% of the initial diameter by adding increasing doses of phenylephrine to the superfusate. We then measured vasodilation by adding increasing doses of the endothelium‐dependent vasodilator acetylcholine (10−9 M to 10−5 M). Vasodilation, serum glucose, uric acid, triglycerides, and free glycerol were not significantly different between groups (p>0.05). To examine the effects of captivity, we compared data to those from previous studies on isolated arteries from wild MODO (WILD). Endothelium‐dependent vasodilation was greater in captive than wild doves (CONT vs. WILD, p<0.01; WB vs. WILD, p<0.05). These findings are consistent with our hypothesis as refined carbohydrate consumption did not impair vasodilation. Moreover, captivity improved vasodilation when compared to wild doves regardless of diet type. The findings contrast with those in mammals, in which high carbohydrate consumption results in impaired endothelium‐dependent vasodilation.Support or Funding InformationThis study was funded in part by an IOSP APS summer research fellowship (WC).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.