Sustainable management of Se-rich silkworm residuals by black soldier flies larvae to produce a high nutritional value and accumulate ω-3 PUFA

Waste disposal and utilisation of its important components are pioneering goals for achieving sustainable development and a clean environment. Silkworm pupae (SWP) are considered a by-product of the sericulture industry and may contain a high concentration of selenium (Se) in some regions, making them a potentially hazardous waste posing health risks. This study examined six treatments of Se-rich SWP (0-100%) as a substrate for black soldier fly (BSF) larvae. Growth performance and protein content of BSF larvae were not affected by increasing SWP content. The total fat, mono-, and poly-unsaturated fatty acids in BSF pre-pupae increased with increasing SWP inclusion in the substrate, from P0 (pre-pupae fed control treatment) through P100 (pre-pupae fed 100% SWP treatment), by 18.83, 61.14, and 62.42%, respectively. The results of significance were: (1) BSF pre-pupae did not accumulate Se, maintaining the same amount of Se in their bodies (similar to 0.18 mg/kg); (2) omega-3 fatty acids represented by linolenic acid in BSF increased by 1,223.35% from P0 to P100, with 70.65% recovered from the SWP; (3) valine percentage increased in BSF compared with the percentage of SWP by 25.30%; and (4) BSF larvae were observed reducing SWP waste by more than one-third. BSF larvae can reduce the waste from sericulture industry and exploit the beneficial properties and components of SWP, converting them into safe and highly nutritious products. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study found that black soldier fly larvae can utilize selenium-rich silkworm pupae as feed without negative effects, while also increasing their fat and protein content. The larvae do not accumulate selenium and can effectively reduce waste from silkworm pupae.