Clean valorization of distillery industry co-product for fish cage aquaculture: a waste-to-wealth approach

The present study investigated the use of brewery waste as a sustainable and cost-effective feed ingredient for Pangasianodon hypophthalmus farming in floating cages in tropical reservoirs. Three isonitrogenous and isocaloric diets were formulated: brewery waste-based floating (T2), brewery waste-based sinking (T3), and soybean meal-based floating (control). Fish fingerlings were fed each diet for 60 days and their growth performance, feed utilization, nutrient retention, and carcass composition were evaluated. Fish fed brewery waste-based floating feed (T2) had the highest weight gain, specific growth rate, and protein efficiency ratio, and the lowest feed conversion ratio. Their growth performance was statistically significant (p < 0.05) compared to fish fed brewery waste-based sinking feed (T3), but not statistically different (p > 0.05) from fish fed soybean meal-based floating feed (control).The cost of brewery waste-based floating feed was 31.45% lower than the cost of soybean meal-based floating feed. Overall, the results of this study suggest that brewery waste is a promising feed ingredient for Pangasianodon hypophthalmus farming in floating cages in tropical reservoirs. It can be used to replace expensive soybean meal without compromising fish growth performance. The use of brewery waste also reduces feed costs and makes cage farming of Pangasianodon hypophthalmus more economically sustainable.