The effect of dietary antioxidants and exercise training on the escape performance of Southern Corroboree frogs

Abstract

Escape-response behaviour is essential to ensure an individual’s survival during a predator attack, however, these behaviours are energetically costly and may cause oxidative stress. Oxidative stress can be reduced by supplementing an individual’s diet with exogenous antioxidants or through regular moderate exercise training, which stimulates the upregulation of the endogenous antioxidant system. Two studies have tested the simultaneous effects of dietary antioxidant supplementation and exercise training on animal escape-response behaviour. The present study investigated the effects of dietary carotenoids and exercise training on the escape-response behaviour of Southern Corroboree frogs. Frogs were fed either a carotenoid-supplemented or unsupplemented diet and were exposed to repeated escape-response trials (training) for five consecutive weeks. Carotenoid-supplemented individuals outperformed unsupplemented individuals in initial hopping speed, length of the first hop and hopping distance, however, the performance of frogs in each treatment group became statistically similar after training. Within treatment groups, exercise training significantly improved the hopping speed of unsupplemented frogs, with speeds almost doubling between training weeks one and five. By contrast, exercise training did not significantly improve the hopping speed of carotenoid-supplemented frogs. Our results provide some of the first evidence that exercise training improves escape performance, and that dietary antioxidants may inhibit training-induced benefits.