A rapid acid hydrolysis method for the determination of chitin in fish feed supplemented with black soldier fly (Hermetia illucens) larvae

Insects are a natural source of feed for fish and have received more attention as a potential source of sustainable high-quality protein. However, contrasting results in different feeding trials have been ascribed to the chitin contained in the exoskeleton of insects and highlighted the importance of developing reliable methods for the quantification of chitin to draw meaningful conclusions about its effect on fish health. A rapid method based on the hydrolysis of chitin into glucosamine and further quantification by liquid chromatography tandem mass spectrometry is evaluated. The method offers good selectivity, linearity, limit of detection (1.08 x 10-5 % w/v or 5.38 x 10-4% w/w), limit of quantification (3.26 x 10-5 % w/v or 1.63 x 10-3 % w/w), trueness (88.39-109.29 %) and precision (2.24-10.72 %). The quantitative method was successfully applied to real samples of fish feed supplemented with chitin from black soldier fly (Hermetia illucens) larvae.