PALATABILITY OF BLACK SOLDIER FLY LARVAL MEAL IN Penaeus vannamei: A BIOCHEMICAL AND IN VIVO COMPARISON WITH SQUID MEAL

Introduction

Squid meal is widely used as a reference palatant in Penaeus vannamei diets, but its reliance on wild fisheries raises concerns over price volatility, supply instability, and ecological impact. Black soldier fly larvae (BSFL, Hermetia illucens) offer a promising alternative through their rich profile of short-chain peptides, free amino acids (fAA) and nucleotides, but their functional efficacy as shrimp palatants remains undercharacterised. This study compared the biochemical composition of a BSFL-derived ingredient with commercial palatants, and assessed if this BSFL-based ingredient could replace squid meal while maintaining or improving feed attractiveness and efficiency in P. vannamei.

Materials and Methods

A 17-day feeding trial was conducted at the RIASEARCH R&D facility (Portugal) using juvenile Penaeus vannamei (initial weight: 7.4 g; 25 shrimp/tank, n=4). Three isonitrogenous and isolipidic extruded diets were tested: a negative control (Control), a 3% squid meal diet (Squid), and a diet in which squid meal was fully replaced by 3% BSFL meal (BSF). Feed intake (%ABW/day) and FCR were calculated at trial end and analysed by one-way ANOVA with Tukey's post-hoc test (p < 0.05).

Selected commercial palatants, including squid meal, were sourced and submitted to physico-chemical characterisation. Nucleotide content was determined by HPLC-UV (ISO 20638:2015, Eurofins, Nantes, France), and protein solubility, molecular weight profile and fAA content (CE 152/2009) were analysed at Upscience (Saint-Nolff, France).

Results

Both the BSF and Squid diets significantly increased relative daily feed intake compared to the Control diet (p < 0.05), with no significant difference detected between BSF and Squid. Numerically, the feed intake of BSF diet was increased by +7.56% relatively to Control (Figure 1). The trial duration (17 days) allowed shrimps to approximately double their weight across all groups. No statistically significant differences in FCR were observed among treatments.

A separate benchmarking of Hilucia™ meal against marine-derived palatants shows that BSFL meal contains markedly higher nucleotide levels (223 mg/100g vs. 27 mg/100g for squid meal), a higher proportion of small peptides (% <1,000 Da; 58.3% vs. 34.1% for squid meal), and comparable soluble protein content (26.9% vs. 25.6% CP). Free amino acid content was also noticeably higher than that of squid meal (1.6% vs. 0.6% DM).

Figure 1. Average daily feed intake of P. vannamei fed either the control diet (Control), the BSFL-based diet (BSF), or the squid meal diet (Squid). Different letters indicate statistically significant differences between groups (p < 0.05).

Discussion

These results confirm that BSFL meal included at 3% exerts a phago-stimulatory effect in P. vannamei comparable to squid meal, while maintaining feed efficiency. This is consistent with its biochemical composition, as nucleotides, short-chain peptides and fAA are recognised feeding stimulants in crustaceans (Suresh et al., 2011; Lee & Myer, 1997). Although the 17-day duration limits conclusions on long-term growth, it was sufficient to double animal weight and calculate FCR, and the absence of differences between BSF and Control groups suggests that increased intake would translate into faster growth at farm scale. Beyond palatability, BSFL ingredients offer meaningful advantages over marine-sourced palatants in terms of supply security, price stability and environmental footprint (Van Phi et al., 2020), complementing a growing body of evidence for beneficial effects of BSFL inclusion on shrimp feed intake, growth and disease resistance (Richardson et al., 2021; Novriadi et al., 2023; Keetanon et al., 2024). Further trials with longer durations and varying inclusion levels should be conducted to confirm dose-response relationships and validate the palatant effect of BSFL meal at commercial scale.

References

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