Black soldier fly life history traits can be influenced by isonutrient-waste-based diets

Abstract

To maximise the black soldier fly (BSF) bioconversion capacity, a waste that is not suitable for use as it is, can have a positive effect if combined with others in a formulation. In this perspective, a total of 3600 of 6-day-old larvae were inoculated on 6 iso-proteic, iso-lipidic and iso-energetic diets (named from D1 to D6; 100 larvae/replicate; 6 replicates/treatment) formulated with 21 by-products. To evaluate growth performance, 30 larvae per replicate were randomly sampled every 4 days until the 40% reached the prepupae phase, in which survival rate (SR), larva-prepupae time duration and bioconversion indexes were calculated. When a pupa was identified, it was moved in the emergence box (23 pupae/treatment) to evaluate the adult parameters: pupa-fly duration time, fly live weight, weight reduction, fly lifespan, puparium weight and emergence rate (ER). Considering SR (>92%) and ER (>94.6%), all diets were suitable for the BSF breeding. The D1 and D5 (composed by brewers spent grain, vegetable and fruit waste) groups overall performed the best larvae growth and development time, while D2 (composed by glaze waste and buffalo milk whey) displayed the worst (p < 0.05). The D5 maintained good weight in prepupae, pupae and adult stages and also D2 reached the same outcome. The bioconversion indexes followed the trend of the larvae performance. In conclusion, the results herein obtained allowed to discriminate the protein, fat and energy variables on the BSF life history traits and observe other factors of influence, such as the ash content, which will need to be evaluated with future research.

HIGHLIGHTS

• Iso-nutrients diets allow to eliminate the lipid/protein and energy effects on the BSF life history traits.

• The use of multiple waste in a diet allows to reduce the inclusion of those that generate better results on growth, which will be most in demand on the market.

Keywords:

• Black soldier fly
• bioconversion efficiency
• diet formulation
• growth
• performance
• substrate pH

Ethical approval and consent to participate

Not applicable.

Authors’ contributions

SBO, IB and LG conceived and designed the experiment. SBO, IB, AR and LG performed the trial and collected the experimental data. SBO and IB analysed the data. SBO carried out the chemical analyses. SBO wrote the first draft of the manuscript. All the authors critically reviewed the manuscript for its intellectual content and gave their approval for the final version to be published.

Disclosure statement

The authors declare that they have no competing interests.

Data availability statement

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This research was supported by the Fondazione Cariplo project CELLOW-FEEP: Circular economy: live larvae recycling organic waste as sustainable feed for rural poultry (ID 2019-1944) and was conducted within the AGRITECH National Research Centre and received funding from the European Union Next-Generation EU (Piano Nazionale di Ripresa e Resilienza (PNRR) – Missione 4 Componente 2, Investimento 1.4 – D.D. 10332 17/06/2022 CN00000022). This manuscript reflects only the Authors’ views and o-pinion, neither the European Union nor the European Commission can be considered responsible for them.