# Effect of Rearing Substrate on Nutritional Composition, Growth Performance and Multi-Omics Characteristics of Black Soldier Fly

## TL;DR

This study shows that rearing black soldier fly larvae on food waste produces the best balance of high protein, fast growth, and efficient resource use, making it ideal for sustainable feed production.

## Contribution

The study identifies food waste as the optimal rearing substrate for black soldier fly larvae, combining high nutritional value and growth efficiency.

## Key findings

- Larvae reared on food waste had the highest protein content and fastest growth.
- Quail feed produced larvae with the highest fat content, while quail manure yielded the highest mineral content.
- Food waste promoted beneficial gut bacteria like Lactobacillus, improving nutrient assimilation.

## Abstract

To address the global shortage of feed protein, this study tested how three rearing substrates—quail feed, food waste, and quail manure—affect the nutrition, growth, and related biological traits of black soldier fly (Hermetia illucens L.) larvae. The results showed food waste led to larvae with higher protein content, faster growth, and efficient material use; quail feed made larvae higher in fat; and the larvae reared on quail manure had the highest total mineral content. The rearing substrates also changed the larvae’s gut bacteria. We conclude that food waste is the most suitable tested substrate for large-scale larval production, as it balances nutrition and cost. This helps alleviate the current shortage of raw materials high in protein and offers a way to reuse food waste, benefiting both agriculture and the environment.

To address global protein shortages, black soldier fly (Hermetia illucens L.) larvae (BSFL) can be used as a sustainable feed alternative, with nutritional quality dependent on rearing substrates. This study compared quail feed (QF), food waste (FW), and quail manure (QM) for BSFL cultivation. Larvae raised on FW and QM had higher crude protein content (47.5–48.3%) than the QF group, while QF-reared larvae contained more fat (33.2%) than the other groups. QM led to larvae with the highest mineral content, and larvae from the FW group showed elevated calcium levels (5.6%). The FW-reared larvae also demonstrated superior growth, with a yield of 186.3 g/kg and a dry-matter conversion rate of 13.7%. Multi-omics analyses indicated substrate-specific differences in gut microbiota and metabolic pathways. FW promoted beneficial bacteria such as Lactobacillus, enhancing nutrient assimilation, while QF and QM upregulated lipid and mineral processing. For sustainable protein production through BSFL rearing, FW was the most suitable substrate among the three tested, offering a balanced combination of high larval protein content and efficient growth.