A potential ingredient for the use in aquafeeds is lauric acid ( hereafter C12), which is predominantly found in coconut oil and has been shown to have virucidal and bactericidal properties. Enrichment of black soldier fly larvae with C12 is possible by using coconut in feeding substrates . The use of black soldier fly larvae has also been shown to have microbial benefits when included in diets.
A growth trial is being conducted to evaluate the effects that C12 and enriched black soldier fly larvae has on the production performance of largemouth bass (LMB ) a growth trial is being conducted. A set of seven isonitrogenous and isolipidic diets were formulated with varying levels of two black soldier fly meals (BSFM; one control and another C12 enriched) and different sources of purified C12. A control diet devoid of C12 was formulated and modified to originate six additional diets containing different concentrations of C12. Diets containing different levels of the BSFM had final C12 concentrations of 1.5%, 2.8%, and 4.5%, and those formulated with the purified source contained 1.6%, 3.5%, and 6.3% C12.
The trial is being conducted in an indoor recirculating aquaculture system comprised of 28, 110-L glass aquaria. Groups of 15 (5.0 g initial weight) LMB were stocked in each aquarium and are being fed twice daily at fixed rates which are adjusted at every two weeks by assessing biomass and survival in each aquarium. Each experimental diet was randomly assorted and assigned to four groups.
During the first three weeks of the experiment the r esults thus far have indicated LMB responded well to dietary BSFM, but growth and feed efficiency tended to reduce as the dietary level of C12 increased (Table 1). When in excess, dietary C12 might have detrimental effects on the production performance of LMB. Results on whole-body proximate composition, fatty acid profiles, and nutrient retention will be presented. Our current findings indicate that BSFM is well utilized by LMB but the concentration of C12 might affect production performance.