Effect of temporary rearing treatment in clear water pond on the quality improvement of largemouth bass (Micropterus salmoides)

Abstract:

Off-flavor problem commonly exists in traditional aquaculture systems, and it has been reported that a temporary rearing model with clean water could remove the off-flavor in fish effectively. In order to study the effect of temporary rearing on off-flavor depuration and fish quality improvement of largemouth bass (Micropterus salmoides), we have cultured fish in pond with Vallisneria spiralis for different time (0, 1, 4, 7, 10, 13, 16 d). The results showed that:(1) The concentration of 2-methylisoborneol (2-MIB) and geosmin (GSM) decreased from (0.42±0.01) μg/kg and (0.54±0.06) μg/kg to (0.33±0.05) μg/kg and (0.35±0.06) μg/kg, respectively (10th day). (2) Moisture of fish muscle was decreased significantly to (74.90±2.40)% (7th day), and ash content was increased significantly to (1.27±0.17)% (7th day). The total sugar content firstly decreased and then recovered to the initial level of (0.49±0.03) g/100 g (13th day). (3) Three kinds of unsaturated fatty acids (C20:3n3, C20:4n3 and C22:4n6) were increased, and 23 kinds of total fatty acids were detected in fish (10th day); there were 16 kinds of free amino acids, and the taste active values (TAV) of amino acids were significantly different through the extension of rearing time (P<0.05), including glutamate (TAV>1) with umami taste and histidine (TAV<1) with bitter taste. (4) After 10 days of temporary rearing, the hardness and chewiness of fish were significantly increased. In conclusion, the temporary rearing in clear water pond planted with Vallisneria spiralis could significantly depurate off-flavor and improve the quality of largemouth bass, and a 10-day temporary rearing is beneficial to both quality and economic value enhancement.