Effects of different inclusion levels of black soldier fly larvae on biochemical composition, water stability and floatability of formulated giant freshwater prawn feed

Abstract

This study aimed to investigate different inclusion levels of black soldier fly larvae (BSFL) meal on water stability and floatability of formulated prawn feed as a steam pellet. In preparation for formulated prawn feed, locally available feed ingredients such as turmeric and tapioca starch were purchased, and the making process of formulated prawn feed as the steam pellet was referred. The formulated prawn feeds were prepared manually with 85%, 80%, and 75% of BSFL meal and labelled as Treatment 1, Treatment 2, and Treatment 3 for additional turmeric, respectively. Water stability and floatation test were performed in triplicates for each treatment to determine the pellet's physical quality. The water stability was carried out in 10 minutes, 20 minutes, and 30 minutes by comparing the stability of the steam pellet when exposed to water of each treatment. In addition, a floatation test was carried out on 5 minutes, 10 minutes, 20 minutes, and 30 minutes. It was observed that the water stability and floatability of steam pellets were affected by the different inclusion levels of BSFL. All treatments of steam pellet with varying levels of inclusion of BSFL meal showed a decreasing trend on water stability and floatability from 85% to 75%. The steam pellet in Treatment 1 with the highest inclusion level of BSFL meal (85%) and the lowest turmeric (5%) had the highest moisture (9.76%), ash (11.39%), total fat (14.45%), protein content (39.28%), and total energy (387.5%) with greater water stability (83%) and greater floatability (86.67%) compared to that of Treatment 2 and Treatment 3 of steam pellet. While considering the better quality of steam pellet, diet in Treatment 1 is recommended due to its highest gelatinisation between BSFL meal and tapioca starch. However, the formulated feed needs some improvement to meet the required demand of M. rosenbergii larvae.