Effects of extrusion conditions on system parameters and physical properties of insect-based fish feed

According to FAO, aquaculture is a growing sector all over the word that should follow a 30 % increase in the coming years. It is therefore necessary to diversify the fish feed used in order to meet the increasing demand. Insect meal is one of the solution proposed as insect breeding is increasing as well. The aim of this study is to evaluate the feasibility of the incorporation of insect meal in extruded fish feed. Impact of formulation (level of incorporation and water content) as well as operating parameters (temperature, screw velocity and feed flowrate) have been studied using an experimental design plan coupled with statistical analysis. The response factors are the most important physical characteristics needed for fish feed, namely, floatability, expansion ratio, density… Results show that moisture content and insect ration are the most impacting parameters on floatability and density, whereas flowrate and temperature impact mainly expansion. Optimisation of the operating parameter is done using the desirability, a function of Statgraphics software that enables the simultaneous optimization of all operating parameters. Results show that insect inclusion increases the total desirability, with an optimal content of 50 %, which was the targeted insect meal replacement.