The Formulation of Aqua Feed Using Locally Sourced Ingredients for Nile Tilapia in The Bahamas

Aquafeeds account for up to 60% of production cost in aquaculture systems, and access to appropriate feeds has been identified as a major inhibitor to the expansion of the aquaculture sector in the Caribbean region. It was proposed that the ability to formulate feed locally would increase farmers’ access to reliable resources using sustainable materials. Effective substitutes to traditional aquafeed ingredients were identified within the Bahamas and used to formulate a trial pellet diet for Nile tilapia. This diet focused primarily on protein [i.e. fish offal (e.g. Nassau grouper and red snapper), spiny lobster discards, black soldier fly larvae and moringa] and carbohydrate (i.e., cassava and brewers spent grain) alternatives; however, it also included other unconventional ingredients such as sweet potato leaves. A comparative analysis was then conducted to investigate the growth and physiological performance of two tilapia strains, red hybrid (Oreochromis spp.) and white hybrid (O. niloticus x O. aureus), fed with either traditional commercial feed or the homemade feed. Experimental tanks were set up containing ten individuals of the two tilapia strains and were fed one of the two diets as follows: T1-Red hybrid x Local diet, T2- White hybrid x Local diet, T3- Red hybrid x Commercial diet, T4- White hybrid X Commercial diet. At the beginning and end of the study period, individuals from each tank were sampled for growth and health parameters including total length (cm), weight (g), girth (cm), and organ weight (liver and heart) as a percentage of body mass to calculate hepatosomatic indices (HPI) and relative ventricular mass (RVM). Over 10 weeks, a 3–5% feed ration was maintained with partial samples being conducted intermittently to determine biomass for feed calculation. Results indicate that while the white hybrid tilapia strain had a higher growth rate than the red hybrid on both diets, both strains reported higher growth rates on the homemade feed than the commercial feed. HPI and RVM were not significantly different between the two diets, suggesting that the homemade feed supports equitable fish growth and health when compared to a commercial feed. While the homemade feed during these initial trials was more expensive to produce, these preliminary results suggests that: 1) locally sourced ingredients do create an equally effective product and 2) that ‘recycling’ from waste streams of other food production ventures, such as the fishing and the brewery industries will promote more sustainable aquaculture systems for the Caribbean region and The Bahamas.