Koene J Peter, Závorka Libor, Pilecky Matthias, Elmer Kathryn R, Adams Colin E
Scottish Centre for Ecology and the Natural Environment (SCENE) University of Glasgow Glasgow UK.
School of Biodiversity, One Health and Veterinary Medicine University of Glasgow Glasgow UK.
Ecol Evol. 2025 Aug 25;15(8):e71924. doi: 10.1002/ece3.71924. eCollection 2025 Aug.
Access to omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) and habitat complexity have been proposed to influence brain development and cognitive ability. We aimed to investigate the physiological and cognitive effects of dietary n-3 LC-PUFA deprivation on juvenile brown trout ( L.) in complex habitats resembling natal stream conditions in which populations have evolved. We tested effects of n-3 LC-PUFA deficiency in diet and habitat complexity on somatic growth, cognitive performance, encephalization, n-3 LC-PUFA biosynthesis and nutrient routing capacity. Brown trout were raised from egg for 7 months post-hatch on either a high (8.91%) or low (1.79%) n-3 LC-PUFA diet; for the final 3 months, trout were further divided into complex (heavily ornamented tanks with small, dynamic, populations) or simple habitats (bare tanks with many, constant, inhabitants). Recognition, memory and inference were tested by comparing the times required to establish stable hierarchical relationships in agonistic dyadic trials featuring naïve trout and trials in which one of the trout had previously observed the other. Gas chromatography and compound-specific stable hydrogen isotope analysis revealed increased biosynthesis and routing of n-3 LC-PUFA to the brain among trout on n-3 LC-PUFA-deficient diets. Fed to satiation, trout did not sacrifice somatic growth to fuel biosynthesis and routing of n-3 LC-PUFA. However, dietary deficiency in n-3 LC-PUFA did lead to smaller brains, and smaller brains were associated with lower cognitive performance. Complex habitats elicited better cognitive performance, and were associated with lower somatic growth, but habitat complexity played only minor roles in encephalization and the n-3 LC-PUFA composition of brain lipids. We conclude that developmental plasticity in response to environment allows brown trout partially to compensate for the paucity of dietary n-3 LC-PUFA, and we suggest that cognitive divergences may play a role in the diversification of life-history variants among brown trout in the wild.
摄入ω-3长链多不饱和脂肪酸（n-3 LC-PUFA）和栖息地复杂性被认为会影响大脑发育和认知能力。我们旨在研究在类似于种群进化的原生溪流条件的复杂栖息地中，日粮缺乏n-3 LC-PUFA对幼年褐鳟（L.）的生理和认知影响。我们测试了日粮中n-3 LC-PUFA缺乏和栖息地复杂性对体细胞生长、认知表现、脑化、n-3 LC-PUFA生物合成和营养物质转运能力的影响。将褐鳟从卵孵化后饲养7个月，分别投喂高（8.91%）或低（1.79%）n-3 LC-PUFA日粮；在最后3个月，将鳟鱼进一步分为复杂栖息地（装饰丰富的水箱，有小型、动态的种群）或简单栖息地（光秃秃的水箱，有许多、恒定的居民）。通过比较在幼稚鳟鱼的争斗二元试验以及其中一条鳟鱼之前观察过另一条鳟鱼的试验中建立稳定等级关系所需的时间，来测试识别、记忆和推理能力。气相色谱和化合物特异性稳定氢同位素分析表明，在缺乏n-3 LC-PUFA日粮的鳟鱼中，n-3 LC-PUFA向大脑的生物合成和转运增加。喂饱后，鳟鱼不会牺牲体细胞生长来为n-3 LC-PUFA的生物合成和转运提供能量。然而，日粮中n-3 LC-PUFA缺乏确实导致大脑较小，而较小的大脑与较低的认知表现相关。复杂栖息地能引发更好的认知表现，且与较低的体细胞生长相关，但栖息地复杂性在脑化和脑脂质的n-3 LC-PUFA组成中仅起次要作用。我们得出结论，对环境的发育可塑性使褐鳟能够部分补偿日粮中n-3 LC-PUFA的缺乏，并且我们认为认知差异可能在野生褐鳟生活史变体的多样化中起作用。
