Effect of diets containing full-fat Hermetia illucens on rainbow trout microbiota: A dual cultivation-independent approach with DGGE and NGS

Given the drift to improve economic and ecological sustainability of the aquaculture sector, novel ingredients fulfilling these requirements are sought. Hermetia illucens, commonly called black soldier fly, (Diptera: Stratiomydae; H) is a promising dietary protein source but its effect on fish gut microbiota is still to be clarified. The aim of the present study was to increase the knowledge of the effect of dietary full-fat H meal on rainbow trout (Oncorhynchus mykiss) microbiota and, in particular, on intestinal mucosa-adherent microbiota by applying a dual approach based on polymerase chain reaction-denaturing gradient gel electrophoresis and high-throughput sequencing of the 16S rRNA gene. Rainbow trout (initial body weight of 137.3 ± 10.5 g) was fed for 98 days with a control diet (H0) containing fishmeal and protein-rich vegetable ingredients and an experimental diet (H50) where 50% of the fishmeal had been replaced by full-fat H meal rich in saturated fatty acids.