Abstract:
Globally, fish production reached 223.2 million tons in 2022, with Sri Lanka contributing
approximately 530,000 metric tons of production annually. However, the
fisheries sector faces inefficiencies across the value chain, with postharvest losses
estimated at 40–60%, corresponding to 200,000–300,000 metric tons of wasted
fish biomass annually, causing both economic losses and environmental burdens.
Concurrently, livestock producers face high feed costs, accounting for 60–70%
of total production expenses. Sri Lanka imported USD 51.6 million worth of
feed ingredients in 2023 due to domestic shortages. Converting underutilized fish
waste into nutrient-rich animal feed offers a dual opportunity to reduce waste and
lower feed costs. Using 25% of the monthly fish waste could potentially yield approximately
118–120 tons of animal feed per month. Processed fish-waste-based
feed has been shown to achieve crude protein levels of 54–57%, lipids 12–17%,
calcium 6–9%, and phosphorus 3–5%, depending on composition and processing
method, demonstrating the feasibility of converting waste into high-quality feed.
This review synthesizes peer-reviewed literature (2000–2025) retrieved from major
academic databases to evaluate the potential of converting fish waste into animal
feed. Technologies including traditional fishmeal and oil production, chemical and
biological silage, novel physiochemical and enzymatic hydrolysis, and advanced
ensiling methods have been reported for their efficacy and nutritional outcomes.
Fish-waste-based animal feeds have been shown to enhance livestock performance,
providing high-quality protein and omega-3 fatty acids. Key challenges include
production limitations, product safety, and scalability feasibility. This review
highlights future research directions for the circular economy and emphasizes the
development of fish waste-based animal feed under the “waste-to-wealth” concept.
Overall, valorizing fish waste represents a viable and sustainable pathway
to reduce environmental pollution, reduce feed import dependency, and improve
resource efficiency in the animal feed sector.
