Evaluating the nutritional potential and microbiome effects of feedinga brewery protein isolate as an alternative to insect meal when fed to Atlantic salmon.

In this study the net protein losses associated with feeding black solider flies (BSF) with brewery waste to produce an insect meal versus producing a protein isolate from such brewery waste using isoelectric precipitation methods were modelled. Following that modelling exercise a brewery protein isolate (BPI) was prepared which had protein levels of 470 g/kg which represented an 80% yield efficiency of the protein and was higher that the BSF meal (395 g/kg). Both the BPI and BSF and a soy protein concentrate (SPC), were then fed to post-smolt Atlantic salmon (Salmo salar), to compare their nutritional qualities. In addition to the characterisation of the composition of each test ingredient, the digestibility and palatability as well as microbiome effects of each ingredient was assessed using a diet-substitution digestibility study approach. For this each of the BPI, BSF, and SPC were included in test diets at 30% inclusion with 70% of each diet coming from the same basal mash. A reference diet was prepared using the same feed preparation methods but based on 100% of the basal mash. Each diet was fed to a tank of thirty-five salmon for a one-week acclimation period before being stripped of faeces, after which the process repeated twice more to generate three replicates through time.

本研究针对以啤酒酿造废弃物饲喂黑水虻（Black Soldier Fly, BSF）制备昆虫蛋白粉，与采用等电沉淀法从同类酿造废弃物制备蛋白质分离物的过程，对二者的蛋白质净损失量开展了建模分析。完成上述建模工作后，研究人员制备了啤酒酿造源蛋白质分离物（Brewery Protein Isolate, BPI），其蛋白质含量达470 g/kg，蛋白质得率为80%，性能优于蛋白质含量为395 g/kg的黑水虻蛋白粉。随后将该BPI、黑水虻蛋白粉与大豆浓缩蛋白（Soy Protein Concentrate, SPC）饲喂至刚完成入海驯化的大西洋鲑（Salmo salar），以对比三者的营养品质。除对各受试原料的组分进行表征外，本研究还通过日粮替代消化试验法，评估了各原料的消化率、适口性及其对肠道菌群的影响。为此，将BPI、黑水虻蛋白粉与SPC以30%的添加比例掺入试验日粮中，每一组试验日粮的其余70%组分均采用统一基础粉料。采用相同的饲料制备工艺，以100%基础粉料制备对照日粮。每个日粮组投喂至装有35尾大西洋鲑的养殖缸中，先进行为期一周的适应驯化，随后收集粪便；该实验流程共计重复两次，最终获得3组时间梯度重复样本。