Algae are natural sources of nutrients, but the presence of anti-nutritional factors often compromises nutrient apparent digestibility coefficients (ADCs) in several fish species. In this study, physical-mechanical and enzymatic technological processing was applied to two seaweeds (Gracilaria gracilis and Ulva rigida) and three microalgae (Nannochloropsis oceanica, Chlorella vulgaris, and Tetraselmis sp.) in order to evaluate its effectiveness in improving nutrient ADC values in diets for European seabass. A practical commercial-based diet was used as reference (REF) and experimental diets were prepared by replacing 30% of REF diet with each test alga used either intact or after processing. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fast performance liquid chromatography (FPLC) analyses revealed that enzymatic processing was more effective than the physical one in changing the protein and peptides composition, increasing the amount of low-molecular-weight compounds in seaweeds and N. oceanica microalgae. Protein digestibility was significantly affected by algae species and in the case of the microalgae by the technological process. Gracilaria gracilis is better digested than U. rigida and physical processing enhanced protein and energy ADC values. Nannochloropsis oceanica and C. vulgaris are better digested than Tetraselmis sp.; the highest protein and energy ADCs were observed in diets containing enzymatically processed N. oceanica (NAN-ENZ) and physically processed C. vulgaris (CHLO-PHY), followed by the diet with physically processed Tetraselmis sp. (TETR-PHY). Results clearly showed that it is possible to increase nutrient accessibility and digestibility of algae by fish, by selecting the most adequate method to disrupt the cell wall. Moreover, the physical-mechanical and enzymatic technological processes used in this study are scalable to the industrial level.

藻类是天然的养分来源，但是抗营养因子的存在通常会损害几种鱼类的养分表观消化率（ADC）。在这项研究中，物理机械和酶促技术处理被应用于两种海藻（Gracilaria gracilis和Ulva刚性）和三种微藻（Nannochloropsis oceanica，Chlorella vulgaris和Tetraselmis）等），以评估其在改善欧洲鲈鱼日粮中营养ADC值方面的有效性。实际的商业饮食被用作参考（REF），实验饮食通过将30％的REF饮食替换为完整或加工后使用的每种测试藻类来制备。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和快速液相色谱（FPLC）分析显示，酶促工艺在改变蛋白质和多肽组成，增加低分子量化合物的数量方面比物理方法更有效。在海藻和N. oceanica微藻中。蛋白质的消化率受藻类的影响很大，对于微藻而言，受工艺过程的影响很大。Gracilaria gracilis比僵硬菌更好地消化，物理处理可提高蛋白质和能量ADC值。Nannochloropsis oceanica和C. vulgaris比Tetraselmis sp。更好地被消化。在含有酶处理饲料中观察到最高的蛋白质和能量的ADC N.大洋洲（NAN-ENZ）和物理加工小球藻（氯仿溶剂PHY），接着用物理加工饮食扁藻属 （TETR-PHY）。结果清楚地表明，通过选择最适当的破坏细胞壁的方法，可以提高鱼类对藻类的营养可及性和消化率。此外，本研究中使用的物理机械和酶促工艺过程可扩展到工业水平。