Potential use of agricultural wastes in aquafeed production

Abstract

Disposal of agricultural wastes are posing environmental hazards which leads to efforts of efficiently utilizing them. This study surveyed a sugar central and a fruit processing plant to collect data on the volume of wastes from representative agricultural crops (e.g. mango, citrus, pineapple, sugarcane, papaya and soybean) in the Philippines during the 2012–2013 and 2014–2015 seasons, respectively. Their potential use in aquafeed was examined in terms of nutritional quality, presence of anti-nutritional factors (ANFs) and pesticide residues. About 40 to 60 % of agricultural wastes generated after processing were peels, pulps or brans, seeds, bagasse, molasses and okara. Most of the agricultural wastes had high levels of fiber and carbohydrate, and low levels of protein, although okara (25 % crude protein) and citrus by-products (11–16 % crude protein) showed acceptable nutritional quality. ANFs such as lignin are largely present in all agricultural wastes, whereas high levels of phenols, and saponins and alkaloids were found in mango seeds and mango peels, respectively. Pesticide residues were detected only in mango and citrus peels but at levels below the maximum residue limits of FAO Codex Alimentarius. From both nutritional and environmental perspectives, agricultural wastes have potential use in aquafeed production but their suitability should be further elucidated in diets for omnivorous fish species such as tilapia.