High activity before breeding improves reproductive performance by enhancing mitochondrial function and biogenesis

Abstract

Understanding of physiological responses of organisms is typically based on data collected during an isolated event. Although many fundamental insights have been gained from these studies, evaluating the response to a single event ignores the fact that each individual has experienced a unique set of events throughout its life that may have altered its physiology. The idea that prior experiences can influence subsequent performance is known as a carry-over effect. Carry-over effects may explain much of the variation in performance found among individuals. For example, high physical activity has been shown to improve mitochondrial respiratory function and biogenesis and reduce oxidative stress, and has been linked to improved health and longevity. In this study, we asked whether the bioenergetic differences between active and inactive individuals carry over to impact performance in a subsequent reproductive event and alter a female's reproductive outcome. Female mice that had access to a running wheel for a month before mating gave birth to a larger litter and weaned a heavier litter, indicating that high physical activity had a positive carry-over effect to reproduction. Mice that ran also displayed higher mitochondrial respiration and biogenesis with no changes in endogenous antioxidant enzymes. These results provide a mechanistic framework for how the conditions that animals experience before breeding can impact reproductive outcomes.

Assessing the fitness consequences of mitonuclear interactions in natural populations

“…Notably, production of ATP and generation of reactive oxygen species (ROS) have been shown to vary with mitochondrial genotype (Ellison & Burton, , ; Estes et al ., ; Hicks, Denver & Estes, ; Barreto & Burton, ; Barreto, Pereira & Burton, ; Latorre‐Pellicer et al ., ). In tractable systems, detailed examination of respiration profiles from isolated mitochondria could also reveal the mechanistic basis for lower fitness in compromised individuals (Chung, Bryant & Schulte, ; Mowry et al ., ; Zhang et al ., ). While rarely adopted, whole‐organism measurements of basal and maximal metabolic rates may also be useful for assessing the fitness consequences of mitonuclear interactions (Sunnucks et al ., ).…”

Ultraviolet irradiation increases size of the first clutch but decreases longevity in a marine copepod

“…Shephard et al (2018) recently characterized the effect of ɣ-radiation on reproductive performance in the cricket Acheta domesticus. Work by Zhang et al (2018) indicated that female mice that ran on a wheel before breeding produced more pups that were heavier at weaning than females that did not have a wheel. While longevity was not reported, they also found an increase in average egg size.…”

“…In addition to exogenous, environmental stressors, endogenous stressors have also been found to benefit organismal performance. Work by Zhang et al (2018) indicated that female mice that ran on a wheel before breeding produced more pups that were heavier at weaning than females that did not have a wheel.…”

Mitochondrial behaviour, morphology, and animal performance

“…oxidative phosphorylation) and exogenous (e.g. radiation) factors and inevitably impact the stability and performance of mitochondria (Zhang et al ., ) and, therefore, whole‐animal performance (Zhang et al ., ; Heine et al ., ).…”