European perch (Perca fluviatilis) fed dietary insect meal (Tenebrio molitor): From a stable isotope perspective

Abstract Stable isotope analysis was conducted to investigate stable isotope ratios of carbon (δ13C) and nitrogen (δ15N), diet-tissue discrimination factors of carbon (Δ13C) and nitrogen (Δ15Ν). Bayesian mixing models were performed to assess relative contribution of insect meal and other ingredients to the development of tissues of European perch (Perca fluviatilis). Accordingly, four experimental formulations, characterized by the increasing inclusion levels of yellow mealworm (Tenebrio molitor) larvae meal (TM) at 0, 6.8, 13.5 and 20.3% as replacement for fishmeal at 0 (TM0), 25 (TM25), 50 (TM50) and 75% (TM75), respectively, were fed to juvenile perch (initial bodyweight, 20.81 ± 3.36 g) in a recirculated aquaculture system for 105 days. δ13C and δ15N of TM were -16.75 and 3.53‰ and significantly distinguished from other terrestrial and marine feed components (P 0.05) but did reduce in muscle (P 0.95). Soy-derived ingredients, soybean meal and soy protein, were an important ingredient in the development of all tissues regardless of dietary TM. The present study provided insightful information on the role of various diet components in perch tissues, which could underlie further development of aquafeed formulations for emerging perch farming in Europe.