A novel carnivorous diet reduces brain telomere length.

Developmental conditions can profoundly influence adult survival or longevity. One established correlate of longevity is the length of telomeres-non-coding DNA regions that protect chromosomal ends. Telomere length in adulthood can be influenced by environmental conditions during development, such as nutrient restriction. Yet, we lack experimental studies of how adult telomere length is affected by a different form of nutritional variation: diet type. Here, we asked how diet-type variation during larval development affects telomere length in multiple post-metamorphic somatic tissues of the Mexican spadefoot (), an anuran species whose larvae develop on two qualitatively distinct diets: an ancestral omnivorous diet of detritus or a more novel carnivorous diet of live shrimp. We found that larvae developing on the novel shrimp diet developed into post-metamorphic frogs with shorter telomeres in the brain-a structure that is particularly vulnerable to harmful effects of nutritional adversity, such as oxidative stress. Given known links between telomere length and neurological health outcomes, our study suggests that a dietary transition to carnivory might carry costs in terms of compromised neural integrity later in life. This work highlights the lasting impact of a developmental diet on somatic maintenance and health.