Methodology
The aquaculture industry is increasingly seeking sustainable alternatives to traditional protein sources. This study evaluated the effects of an experimental diet containing insect meal on the growth performance, feed efficiency, yield indices, and tissue morphology of juvenile Largemouth Bass (Micropterus salmoides) in a recirculating aquaculture system. Two experimental diets were formulated with identical compositions, except that one included 15% Black Soldier Fly (Hermetia illucens) meal as a replacement for soybean meal used in the scientific control. Both experimental formulations were compared against a standard commercial control. A total of 400 fish (70.7 ± 17.9 g) of mixed sex were randomly distributed into nine tanks (50 fish per tank), with three replicate tanks per dietary treatment. Fish were hand-fed once daily at 1.5% of body weight, five days per week for five months under natural photoperiod at a mean water temperature of 21.5 °C. Furthermore, a carbon footprint assessment was conducted using literature and database data.
Results and Discussion
Both experimental diets significantly outperformed the commercial control in terms of final weight and length, while no significant differences were observed between the BSF-inclusive diet and the experimental control. This indicates that BSF meal performs as effectively as a standard high-quality formulation. Feed efficiency was notably improved in both experimental groups, characterized by a lower feed conversion ratio (FCR) and a higher specific growth rate (SGR). While somatic indices showed enhanced fillet yield in experimental groups, histological analysis confirmed a satisfactory health status across all treatments. Intestinal histomorphometry remained unaffected by diet, proving that BSF meal maintains intestinal integrity. Furthermore, reduced hepatocyte vacuolization in both experimental groups suggests improved hepatic cellular integrity compared to the commercial control. The environmental assessment demonstrated that BSF meal inclusion reduced the carbon footprint by approximately 20% (2.09 vs 2.66 kg CO2 eq. kg-1 feed). These results highlight BSF meal as a sustainable, high-performance protein source that matches the efficacy of standard experimental diets while offering significant environmental benefits for M. salmoides production.
Acknowledgment
The FIT-BASS project was funded under the Cascade Calls of the Spoke 5 on the AGRITECH Program -"National Research Centre for Agricultural Technologies", from the National Recovery and Resilience Plan (NRRP) Funds, Mission 4 Education and Research - Component 2 "From Research to Enterprise" - Investment 1.4, funded by the European Union – NextGenerationEU.