Cumulative changes of off-flavor compounds of grass carp in two culture systems

In order to investigate the influence of culture systems on the accumulation of off-flavor substances in the aquaculture water and grass carp (Ctenopharyngodon idella), we studied the accumulation of geosmin (GSM) and 2-methylisoborneol (2-MIB) in the fish in the in-pond raceway system (IPRS) and the traditional culture system. We dynamicaclly detected the contents of the two compounds in the water and fish muscles in different culture systems and applied the Pearson analysis. The results show that the 2-MIB concentration in the water and fish muscle in the IPRS system increased significantly with the extension of aquaculture time. The GSM concentration also showed a gradual accumulation trend, and the changes in the concentrations of the two compounds in the muscle remained consistent with those in the water. In the traditional pond system, the concentration of 2-MIB gradually increased without significant difference, and the fish muscle had significantly higher concentration at the end of the experiment than at previous stages. The GSM concentration of both pond water and fish muscle first decreased and then increased. Correlation analysis shows that the accumulation of both GSM and 2-MIB was positively correlated with fish body mass and length. In conclusion, the accumulation of off-flavor compounds in pond water and fish muscle is affected by the culture system. Grass carp with body mass of 0.42–1.23 kg accumulates off-flavor compounds faster.