AQUA 2024

August 26 - 30, 2024

Copenhagen, Denmark

BLACK SOLDIER FLY LARVAE MEAL IN FEEDS TO ATLANTIC SALMON IN FRESHWATER AND SEAWATER

Bogevik A.S.1*, Kokkali M.1, Samuelsen T.A.1 and Kousoulaki K.1

1Nofima, Nutrition and Feed Technology, Bergen, Norway

* andre.bogevik@nofima.no

 



Black soldier fly larvae (BSFL) is a novel raw material in aquafeeds and can be processed similarly to fish meal by fractionation in solids, stickwater, and oil. The fish meal stickwater has a high content of low-weight molecular components that are essential -in a high-quality fish meal- for feed intake, growth, and overall health in Atlantic salmon (Salmo salar). For optimal utilization of stickwater, the moisture content of the fraction has to be reduced before being combined with the solid phase to produce a meal that is dried and grained to specifications needed for optimal utilization in feeds and prolonged shelf life. Special equipment and knowledge are needed, but this process will improve the ingredient’s sustainability, as well as technical and nutritional quality. BSFL meal produced by Innovafeed (France) was used in two trials with salmon in the Research Council of Norway-funded project Millennial Salmon (#319987). Atlantic salmon parr (26g) reared in freshwater were given five feeds across triplicate tanks. These included a control diet and 4 test diets where 10% of fish meal was substitiuted with BSFL meal, with an increasing ratio of BSFL stickwater : solids ratio. The experiment lasted for 8 weeks to study the growth, digestion, and welfare of fish fed the respective diets. BSFL meal with stickwater was further used in a 3-component mixture design with fish meal and soy protein concentrate. In total, seven feeds were formulated, varying in proportions: 75 – 275 g kg-1 fish meal, 23 – 223 g kg-1 soy protein concentrate, and 0 – 200 g kg-1 BSFL with stickwater. These feeds were given to Atlantic salmon post-smolts (258g) reared in seawater, across triplicate tanks for a duration of12 weeks. Both freshwater and seawater experiments showed that BSFL meal is a potential protein source in aquafeeds that can effectivelly substitute portions of fish meal and soy without affecting feed intake or growth. However, it was observed that high inclusion of BSFL meal could result in reduced growth rates for Atlantic salmon, particularly in feeds with low fish meal content. Extended results from the experiments will be presented at the conference.