Comparative evaluation ofHermetia illucens larvae reared on different substrates for red tilapia diet: effect on growth and body composition

Abstract

Black soldier fly larvae (BSFL;Hermetia illucens) can be a very beneficial source of protein to replace fishmeal for fish feed, but little is known about the impact of their growing substrate on the performance and nutritional composition of the fish consuming them. In this study, BSFL were reared on two different substrates; palm oil decanter cake (DC) and coconut pulp (CP) for 35 days before processing and including them in tilapia diet with 50% inclusion level. The weight and length of the BSFL as well as waste reduction efficiency was observed. The fish were assigned to three different diets, namely DC50 (50% BSFL from DC), CP50 (50% BSFL from CP) while 100FM (100% fishmeal) is treated as a control. The fish performance, feed efficiency and nutritional composition of their body after 4-weeks of feeding trial were observed. The results indicate that BSFL cultured in DC obtained higher body weight gain but less efficient in reducing waste compared to those cultured in CP. The utilisation of 50% inclusion level of BSFL cultured in DC for tilapia diet improves growth and feed efficiency. However, the inclusion of all experimental diets has a less pronounced effect on protein and ash body composition; although fish fed with CP50 has the least lipid body composition compared to other treatments. The experiment demonstrated that replacement of fishmeal by BSFL cultured in different substrates would influence the performance of fish consuming it. Results of the present study will offer an optimal solution, especially for large-scale commercial BSFL cultivation.