Redfern Julia C, Cooke Steven J, Lennox Robert J, Nannini Michael A, Wahl David H, Gilmour Kathleen M
Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, Canada.
Physiol Behav. 2017 Oct 15;180:15-24. doi: 10.1016/j.physbeh.2017.08.001. Epub 2017 Aug 4.
Cortisol, the main glucocorticoid stress hormone in teleost fish, is of interest as a mediator of maternal stress on offspring characteristics because it plays an organizational role during early development. The present study tested the hypothesis that maternal exposure to cortisol treatment prior to spawn affects offspring phenotype using wild largemouth bass (Micropterus salmoides). Baseline and stress-induced cortisol concentrations, body size (i.e. length and mass), and behavior (i.e. anxiety, exploration, boldness, and aggression) were assessed at different offspring life-stages and compared between offspring of control and cortisol-treated females. Cortisol administration did not affect spawning success or timing, nor were whole-body cortisol concentrations different between embryos from cortisol-treated and control females. However, maternal cortisol treatment had significant effects on offspring stress responsiveness, mass, and behavior. Compared to offspring of control females, offspring of cortisol-treated females exhibited larger mass right after hatch, and young-of-the-year mounted an attenuated cortisol response to an acute stressor, and exhibited less thigmotaxic anxiety, exploratory behavior, boldness and aggression. Thus, offspring phenotype was affected by elevated maternal cortisol levels despite the absence of a significant increase in embryo cortisol concentrations, suggesting that a mechanism other than the direct deposition of cortisol into eggs mediates effects on offspring. The results of the present raise questions about the mechanisms through which maternal stress influences offspring behavior and physiology, as well as the impacts of such phenotypic changes on offspring fitness.
皮质醇是硬骨鱼体内主要的糖皮质激素应激激素，由于其在早期发育过程中发挥组织作用，作为母体应激对后代特征的介导因子而备受关注。本研究使用野生大口黑鲈（Micropterus salmoides）检验了母体在产卵前接触皮质醇处理会影响后代表型的假设。在不同的后代生命阶段评估了基线和应激诱导的皮质醇浓度、体型（即长度和质量）以及行为（即焦虑、探索、大胆和攻击性），并比较了对照雌鱼和经皮质醇处理的雌鱼的后代。皮质醇给药不影响产卵成功率或时间，经皮质醇处理的雌鱼和对照雌鱼的胚胎之间全身皮质醇浓度也没有差异。然而，母体皮质醇处理对后代应激反应性、质量和行为有显著影响。与对照雌鱼的后代相比，经皮质醇处理的雌鱼的后代在孵化后立即表现出更大的质量，当年幼鱼对急性应激源的皮质醇反应减弱，并且表现出更少的趋触性焦虑、探索行为、大胆和攻击性。因此，尽管胚胎皮质醇浓度没有显著增加，但后代表型受到母体皮质醇水平升高的影响，这表明除了皮质醇直接沉积到卵中之外，还有其他机制介导对后代的影响。本研究结果引发了关于母体应激影响后代行为和生理的机制以及这种表型变化对后代适应性影响的问题。
