Data Sheet 1_Fatty acid profile of Gammarus locusta newly hatched offspring from the wild and from adults farmed on mono-specific macroalgal diets.docx

The accelerated growth of marine aquaculture targeting species that require formulated aquafeeds creates a pressing need to find new sustainable ingredients and additives that can secure a premium farming performance, as well as the nutritional value of farmed species. Marine gammarid amphipods can be an excellent source of essential fatty acids (FA), namely, long-chain n-3 polyunsaturated FA (LC-PUFA). However, their potential contribution to aquaculture feeds remains largely unexplored. The present work evaluated the effect of five mono-specific macroalgal diets (Ulva sp., Fucus sp., Laminaria sp., Gracilaria sp., and Chondrus sp.) on the FA composition of the offspring of Gammarus locusta fed on these macroalgae and compared it with the offspring of wild conspecifics. Results revealed that offspring from wild G. locusta showed the highest amount of PUFA (4.95 ± 0.31 μg mg-1 DW), as well as essential FA, namely eicosapentaenoic acid (EPA, 20:5n-3) (2.49 ± 0.21 μg mg-1 DW) and docosahexaenoic acid (DHA, 22:6n-3) (0.87 ± 0.16 μg mg-1 DW). The treatment with the highest amount of PUFA and EPA was the one using Fucus sp. as a mono-specific macroalgal diet (4.46 ± 0.31 μg mg-1 DW and 2.42 ± 0.24 μg mg-1 DW, respectively). The best levels of DHA in offspring were recorded for specimens feeding on Chondrus sp. (0.56 ± 0.10 μg mg-1 DW). Significant differences in the abundance of stearic acid (18:0) and DHA were observed between the offspring of adults fed algal-based diets and those from the wild. These findings suggest that G. locusta selectively conserves and directly or indirectly biosynthesises essential FA for growth and reproduction, particularly LC-PUFA. Overall, G. locusta can perform a trophic upgrade of its diet, making this gammarid amphipod a promising additive for the formulation of high-quality aquafeeds supplying LC-PUFA.

以需配合饲料的海水养殖物种为目标的海水养殖产业加速扩张，亟需开发新型可持续原料与添加剂，以保障养殖生产性能与养殖物种的营养价值。海洋钩虾类端足类（marine gammarid amphipods）可作为必需脂肪酸（fatty acids, FA）的优质来源，具体为长链n-3多不饱和脂肪酸（long-chain n-3 polyunsaturated FA, LC-PUFA）。然而其在水产养殖饲料中的应用潜力仍未得到充分探索。本研究评估了5种单种大型藻类饲料（石莼属Ulva sp.、墨角藻属Fucus sp.、海带属Laminaria sp.、江蓠属Gracilaria sp.、角叉菜属Chondrus sp.）对以这些藻类为食的洛氏钩虾（Gammarus locusta）后代脂肪酸组成的影响，并将其与野生同类的后代进行了对比。结果显示，野生G. locusta的后代多不饱和脂肪酸（polyunsaturated FA, PUFA）含量最高，达(4.95 ± 0.31) μg·mg⁻¹干重（dry weight, DW），其必需脂肪酸含量亦居首位，具体为二十碳五烯酸（eicosapentaenoic acid, EPA, 20:5n-3，(2.49 ± 0.21) μg·mg⁻¹ DW）与二十二碳六烯酸（docosahexaenoic acid, DHA, 22:6n-3，(0.87 ± 0.16) μg·mg⁻¹ DW）。多不饱和脂肪酸与EPA含量最高的处理组为以墨角藻属（Fucus sp.）作为单种大型藻类饲料的组别，对应含量分别为(4.46 ± 0.31) μg·mg⁻¹ DW与(2.42 ± 0.24) μg·mg⁻¹ DW。后代中DHA水平最优的样本取自以角叉菜属（Chondrus sp.）为食的个体，为(0.56 ± 0.10) μg·mg⁻¹ DW。对比投喂藻类基饲料的亲虾后代与野生亲虾后代，发现硬脂酸（18:0）与DHA的丰度存在显著差异。上述研究结果表明，G. locusta可选择性保留并直接或间接生物合成用于生长与繁殖的必需脂肪酸，尤其是长链n-3多不饱和脂肪酸。总体而言，G. locusta可实现其日粮的营养级升级，使得该钩虾类端足类成为配制富含长链n-3多不饱和脂肪酸的优质水产养殖饲料的极具前景的添加剂。