Comparison between Gray (FRPC) and Brown (FRPM) Fish Waste Meals: Proximate Composition and Potential Applications

The increase in fish consumption has raised waste generation along the production chain, which is often underutilized, leading to environmental impacts and economic losses. This work aimed to compare the physicochemical characteristics of two types of meals (Gray Fish Waste Meal - GFWM and Brown Fish Waste Meal - BFWM) produced from waste (heads, fins, and spines) of Nile Tilapia (Oreochromis niloticus), Pirapitinga (Piaractus brachypomus), and Tambaqui (Colossoma macropomum). The GFWM was obtained from noble parts (fillet trimmings), while the BFWM was produced from the integral grinding of all the waste. The materials were obtained from the Aquaculture Station of the Federal University of Delta do Parnaíba (UFDPar). The meals from each species were produced in separate batches by oven-drying at 60°C for 24 hours and grinding. Proximate composition analyses were performed according to the Association of Official Analytical Chemists (AOAC, 2006). The results revealed significant differences (p < 0.05) between the meals: the GFWM showed higher protein (51.14%) and ash (28.94%) contents, while the BFWM stood out for its higher lipid content (13.16%) and lower moisture (3.18%). The caloric value of the BFWM (345.53 kcal/100g) was higher than that of the GFWM (285.38 kcal/100g), reflecting its higher energy density. It is concluded that both meals have high potential as food ingredients. The GFWM, rich in proteins and minerals, is ideal for diets requiring protein and mineral support, such as in aquaculture. The BFWM, with its high lipid content and low moisture, is more suitable for high-energy yield feeds, such as for poultry and swine. The choice between them should consider specific nutritional requirements, costs, and feasibility. Furthermore, it is recommended to explore the use of these meals in products like bread, cakes, snacks, and meat products, aiming to broaden the sustainable use of fishing waste and promote food security. Future studies on digestibility and in vivo efficacy are necessary to validate their application on a commercial scale.