Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada.
Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada.
Comp Biochem Physiol A Mol Integr Physiol. 2019 Mar;229:25-32. doi: 10.1016/j.cbpa.2018.11.017. Epub 2018 Nov 29.
The negative effects of abiotic and biotic stressors on animal condition, physiology, behaviour, and fitness have become increasingly recognized, making it critical to understand how these may be mitigated, such as through diet. When consumed, dietary antioxidants (secondary metabolites produced by plants) provide protection from oxidative damage that can result from exposure to stressors. We examined the effects of dietary antioxidants (β-carotene and vitamin E) on the ability of Lithobates sylvaticus (wood frog) tadpoles to overcome the detrimental effects imposed by two common environmental stressors - exposure to the herbicide atrazine or infection by a pathogenic helminth parasite (Echinostoma trivolvis). Tadpoles which were fed high concentrations of either vitamin E or β-carotene had a greater immune response compared to those given trace diets of either compound as measured by circulating white blood cells and a phytohemaglutination assay (PHA). Similarly, tadpoles in the herbicide and parasitism treatments that were given trace antioxidant diets had significant weight loss, whereas those consuming high levels of vitamin E or β-carotene did not. Our results suggest that dietary antioxidants, specifically β-carotene and vitamin E, have a positive effect on tadpole immune systems and overall condition that likely allows them to better cope with natural stressors, with potential implications for their foraging behaviour.
非生物和生物胁迫因素对动物的健康、生理、行为和适应能力的负面影响已逐渐被认识到，因此了解如何减轻这些影响变得至关重要，例如通过饮食。当摄入时，膳食抗氧化剂（植物产生的次生代谢物）可以提供保护，防止因暴露于胁迫因素而导致的氧化损伤。我们研究了膳食抗氧化剂（β-胡萝卜素和维生素 E）对 Lithobates sylvaticus（林蛙）蝌蚪克服两种常见环境胁迫因素——暴露于除草剂莠去津或感染致病性寄生蠕虫（Echinostoma trivolvis）——不利影响的能力的影响。与给予痕量饮食的化合物相比，摄入高浓度维生素 E 或 β-胡萝卜素的蝌蚪具有更大的免疫反应，这可以通过循环白细胞和植物血凝素测定法（PHA）来衡量。同样，在接受除草剂和寄生虫处理的蝌蚪中，给予痕量抗氧化剂饮食的蝌蚪体重显著减轻，而摄入高浓度维生素 E 或 β-胡萝卜素的蝌蚪则没有。我们的结果表明，膳食抗氧化剂，特别是 β-胡萝卜素和维生素 E，对蝌蚪的免疫系统和整体健康状况有积极影响，这可能使它们能够更好地应对自然胁迫因素，对它们的觅食行为有潜在影响。
