Utility of by-products of black soldier fly larvae (Hermetia illucens) production as feed ingredients for Pacific Whiteleg shrimp (Litopenaeus vannamei)

Abstract

Projected growth in insect production as alternative feedstuffs will yield novel by-products that are potentially valuable for aquafeed applications. We analyzed the nutrient composition of three by-products occurring from black soldier fly larvae production (exuvia, cocoon, imago) and the bioavailability of key nutrients for Pacific Whiteleg shrimp (Litopenaeus vannamei). Protein accounted for 317 g kg⁻¹ in exuviae, 433 g kg⁻¹ in cocoons, and up to 521 g kg⁻¹ in adult flies (imagines). Considerable amounts of essential amino acids were detected in imago meal, which significantly matched the ideal dietary amino acid composition for penaeid shrimp (r² = 0.66, p = 0.0076). Exuviae and cocoons contained moderate amounts of lipids (64–140 g kg⁻¹), while imagines comprised 356 g kg⁻¹ total lipid. Saturated fatty acids predominated in all insect materials (47%–83% of total fatty acids). Chitin concentration was highest in cocoons and exuviae (154 and 139 g kg⁻¹) and low in imagines (51 g kg⁻¹). A feeding trial with shrimp, L vannamei, revealed apparent digestibility coefficients of 20%–59% for protein, 24%–54% for energy, 25%–49% for carbon, and 27%–68% for copper. Defatting of imago meal increased the digestibility of protein, energy, and carbon by 77%, 64%, and 61%, respectively. Defatted imago meal can serve as a protein supplement for shrimp diets.