Preparation of fish oil nanospheres for shrimp feeds

The aim of this work is to fabricate the encapsulated fish oil particles for shrimp feed. The co-encapsuted fish oil with BHT (Butylated hydroxytoluene as the antioxidant) particles size is 1.00 ± 0.74 mm prepared solvent displacement method using ethylcellulose as the polymeric material. The morphology of these particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The encapsulated fish oil-BHT particles were tested to investigate the stability properties. The results indicate that encapsulated fish oil-BHT processes better thermal stability, oxidative stability and shelf life stability than unencapsulated fish oil. Moreover, encapsulated fish oil-BHT particles were added into the shrimp feed to increase the content of unsaturation of polyunsaturated fatty acids (PUFAs) in shrimp diet. The shrimp feeds were prepared with two different methods: 1) mixing encapsulated fish oil-BHT particle to shrimp feed paste for pelting machine before pelleting, 2) spraying encapsulated fish oil-BHT particle suspension onto the shrimp feed pellets. Both methods gave feed with minimal degradation of unsaturation functionality. In addition, Litopenaeus vannamei fed with feed containing the encapsulated fish oil-BHT particle shows better health such as, growth, weight, length and immunity index than those fed with unencapsulated fish oil containing feed.

本研究旨在制备用于虾饲料的微胶囊化鱼油颗粒。以乙基纤维素（ethylcellulose）为高分子载体材料，采用溶剂置换法（solvent displacement method）制备得到负载抗氧化剂二叔丁基对甲酚（Butylated hydroxytoluene, BHT）的复合微胶囊化鱼油颗粒，其粒径为1.00 ± 0.74 mm。采用扫描电子显微镜（scanning electron microscopy, SEM）与透射电子显微镜（transmission electron microscopy, TEM）对该颗粒的形貌进行了表征。对该鱼油-BHT微胶囊颗粒的稳定性性能开展了测试与表征。结果表明，相较于未微胶囊化的鱼油，鱼油-BHT微胶囊具备更优异的热稳定性、氧化稳定性以及货架期稳定性。此外，将鱼油-BHT微胶囊颗粒添加至虾饲料中，可提升虾饲料日粮中多不饱和脂肪酸（polyunsaturated fatty acids, PUFAs）的不饱和组分占比。本研究采用两种不同工艺制备该添加型虾饲料：1）在制粒前将鱼油-BHT微胶囊颗粒混入虾饲料浆料中，随后投入制粒机制备颗粒饲料；2）将鱼油-BHT微胶囊颗粒悬浮液喷涂至成型后的虾饲料颗粒表面。两种工艺制备的饲料均能最大程度保留多不饱和脂肪酸的不饱和官能团活性。此外，饲喂添加鱼油-BHT微胶囊颗粒饲料的凡纳滨对虾（Litopenaeus vannamei），其生长性能、体质量、体长以及免疫指标均优于饲喂添加未微胶囊化鱼油饲料的对照组对虾。