Characterizing the Role of Dietary Antioxidants as Immune-enhancing Molecules in Larval Anurans

The effects of stress (disruption of homeostasis) and stressors (factors that cause changes in homeostasis) and their impacts on animal health, physiology, behaviour and fitness have received enormous attention within the scientific community. From an evolutionary stand point, understanding the way in which animals cope with stress or how stress tolerance has evolved is important, as chronic stress can lead to loss of fitness. From an ecological stand point, identifying stressors within the environment and understanding how additive stressor effects can impact the way in which animals cope is crucial for understanding population declines and or possible extinctions. One coping mechanism used by some animal taxa is diet. When consumed, dietary antioxidants (secondary metabolites produced by plants) can provide protection from oxidative damage that can result from exposure to stressors. My dissertation focuses on the effects of these compounds on tadpole immune function. I choose to focus on tadpoles, as populations of numerous amphibian species are declining worldwide and some have gone extinct. In addition, tadpoles, which are strictly aquatic, are exposed to a wide variety of both abiotic and biotic stressors. I focus on three areas of study: 1) the effect of dietary antioxidants and natural stressors on immune function; 2) whether or not tadpoles detect these compounds in their food and whether or not they have the ability to self-medicate; 3) a potential trade-off between immune function and antipredator defense mediated by dietary antioxidants and the environmental availability of these compounds in natural tadpole habitats. My work will contribute to the field of ecology and amphibian biology by investigating the effects of these potentially beneficial compounds and the effects on amphibian immune function, in an attempt to determine if there are any natural immune enhancers to help amphibian's combat mortality via immunosuppression.Ph.D.2016-11-30 00:00:0