Universidade de Passo Fundo (UPF), Curso de Medicina Veterinária. Campus I, Bairro São José, Caixa Postal 611, CEP 99001-970 Passo Fundo, RS, Brazil.
Physiol Behav. 2012 Oct 10;107(3):397-400. doi: 10.1016/j.physbeh.2012.09.008. Epub 2012 Sep 25.
In many vertebrate species, including humans, the developmental stage directly influences an organism's reactivity to stress. For instance, fishes appear to exhibit "stress insensitive" periods early in development, which contributes to important alterations in stress responses. This phenomenon raises the important question of whether size or age influences fish stress responses, as there may be large discrepancies in size at any stage of ontogeny. We therefore posed the following question: what key role does the age and/or weight/length of fish play in contributing to different stress levels? To address this question, we conducted 2 simple experiments to compare the cortisol response to stress in the fish Rhamdia quelen. In the first experiment, we compared the cortisol response of fish of 2 different age groups (3 vs. 12 months) with the same body size, whereas in the second experiment we compared 2 groups of the same age (3 months) but with different body sizes. The results showed a similar stress response in fish of the same age but different size, but a large difference in the stress response in fish of the same size but different age. Both tests indicate that age is the determining factor for the functioning of the hypothalamo-pituitary-interrenal (HPI) axis, and is probably related to the stage of maturation. This study makes a significant contribution to our knowledge of the stress, behavior, and welfare of fish of different age classes, primarily with respect to the timing of measurements and the accurate determination of fish age, regardless of size.
在许多脊椎动物物种中，包括人类，发育阶段直接影响生物体对压力的反应性。例如，鱼类在发育早期似乎表现出“压力不敏感”期，这导致了压力反应的重要改变。这种现象提出了一个重要的问题，即大小或年龄是否会影响鱼类的应激反应，因为在任何发育阶段，大小可能存在很大差异。因此，我们提出了以下问题：鱼类的年龄和/或体重/长度在多大程度上对不同的应激水平有贡献？为了解决这个问题，我们进行了 2 个简单的实验，比较了虹鳉鱼的皮质醇对压力的反应。在第一个实验中，我们比较了 2 个不同年龄组（3 个月和 12 个月）的鱼类的皮质醇反应，它们具有相同的体型，而在第二个实验中，我们比较了 2 个相同年龄组（3 个月）但体型不同的鱼类。结果表明，体型相同但年龄不同的鱼类的应激反应相似，但体型相同但年龄不同的鱼类的应激反应差异很大。这两个测试都表明，年龄是下丘脑-垂体-肾上腺（HPI）轴功能的决定因素，可能与成熟阶段有关。这项研究对我们了解不同年龄组鱼类的应激、行为和福利做出了重要贡献，主要涉及测量时间和鱼类年龄的准确确定，无论大小如何。
