Evaluation of post-consumer food waste as partial replacement of commercial feed in marbled rabbitfish, Siganus rivulatus aquaculture

Abstract

Food waste remains as one of the most serious environmental challenges facing the world today, with sizable quantities generated and disposed of in landfills. Accordingly, exploring solutions to mitigate the detrimental impacts of such waste becomes vital. Aquaculture, a rapidly growing industry in rural areas of developing nations, offers the potential of using this waste productively to partially replace commercial feed, which is often absent or expensive. The present study delves into new options of using plate food waste collected from local restaurants as fish feed supplementation. Food waste, collected and processed into pellets, was evaluated in an 8-week feeding trial of rabbitfish, Siganus rivulatus. Five feeding regimens were adopted in which commercial feed was substituted with waste-based feed at 0, 25, 50, 75 and 100% of daily offering. Results suggest that up to 73.2% of the commercial feed can be substituted by waste-based feed with no significant effects on survival, growth rate, feed conversion ratio, or hepatosomatic and viscerosomatic indices of the fish. There were no statistical differences among treatments with 0, 25 and 50% replacement in terms of whole-body protein and lipid content or in hematological parameters. However, at 75% substitution, there was a clear decrease in growth, whereas at 100% replacement the fish showed complete mortality. Therefore, this study demonstrates a potential solution to mitigate food waste from landfills by utilizing it as a partial replacement of commercial fish feed. This in turn decreases the cost incurred in aquaculture production.