Fish Ethology and Welfare Group, CCMAR, Faro, Portugal.
Fish Ecology Group, IMEDEA (CSIC/UIB), Esporles, Spain.
Sci Rep. 2020 Jul 9;10(1):11252. doi: 10.1038/s41598-020-68306-6.
Environmental enrichment is considered as a recommended tool to guarantee or improve the welfare of captive fish. This study demonstrates for the first time that structural environmental enrichment enhances cognition, exploratory behaviour and brain physiological functions of gilthead seabream (Sparus aurata). Seabream was reared in groups (n = 15) during 60 days under two different treatments: enriched tanks with plant-fibre ropes (EE) or bare/non-enriched tanks (NE). Fish were then exposed to a purpose-built maze for 1 h every second day in four trials. Analysis of video recordings showed that seabream under EE conditions presented higher overall exploratory behaviour, spatial orientation and learning capability compared to seabream from NE conditions. Results from brain monoamines analyses may suggest increased recent dopaminergic activity in telencephalon, known to be involved in learning processes; and increased serotonergic activity in cerebellum, involved in the coordination of balance, movements and orientation. In addition, EE-reared fish showed increased antioxidant activity in whole brain, with no apparent oxidative damage. Structural EE seemed to induce an hormetic response on juvenile seabream, improving their welfare status during captivity. Application of this kind of physical structure might be feasible at fish farms as a passive and non-invasive tool to improve welfare of intensively cultured seabream.
环境丰容被认为是一种保证或提高圈养鱼类福利的推荐工具。本研究首次表明，结构环境丰容增强了真鲷（Sparus aurata）的认知、探索行为和大脑生理功能。在 60 天的时间里，真鲷被分为两组（n=15）进行养殖：一组在有植物纤维绳的丰容缸中（EE），另一组在没有丰容的缸中（NE）。然后，这些鱼在四个试验中，每隔一天在一个专门建造的迷宫中暴露 1 小时。对视频记录的分析表明，与来自 NE 条件的真鲷相比，EE 条件下的真鲷表现出更高的整体探索行为、空间定向和学习能力。来自脑单胺分析的结果可能表明，大脑中与学习过程有关的端脑多巴胺活性增加，与平衡、运动和定向协调有关的小脑 5-羟色胺活性增加。此外，EE 饲养的鱼在整个大脑中表现出更高的抗氧化活性，没有明显的氧化损伤。结构丰容似乎对幼年真鲷产生了一种应激反应，改善了它们在圈养期间的福利状况。这种物理结构的应用在养殖场可能是可行的，作为一种被动和非侵入性的工具，可以提高集约化养殖真鲷的福利。
