Thermal acclimation of fast-growing Japanese Quails (Coturnix japonica) exhibit decreased oxidative stress and increased muscle fiber diameters after acute heat challenges

Abstract

Many predict dire consequences of increasing temperatures; however, high temperatures in early life may aid animals during extreme thermal events later in life. The underlying physiological mechanisms have not been elucidated. We examined whether developing in warmer temperatures would physiologically benefit adult Japanese Quails (Coturnix japonica Temminck and Schlegel, 1849) by exploring changes in oxidative stress and muscle structure in two quail lines — one selected for control growth and another for fast growth and after acute heat challenges. We used a factorial design to administer four treatment combinations to each line: an initial period of either heat-stress acclimation (3 h every other day to 37 °C) or no acclimation, and after 5 weeks, either an acute heat-stress challenge (8 h at 39 °C) or no challenge. We found that control quails had significantly higher citrate synthase activity than fast-growing quails. Fast-growing quails had higher hydroxyl scavenging capacity than control quails. Peroxyl scavenging capacity decreased in both lines after an acute heat challenge, regardless of acclimation. Finally, fast-growing quails had larger muscle fiber diameters than control quails, and acclimated birds that experienced an acute heat challenge had larger muscle fibers than those that did not experience a heat challenge. Thus, fast-growing quails may physiologically benefit from developing in warmer temperatures.