ZHOU Dan;NI Meng;LIU Mei;ZOU Songbao;XU Qing;GU Zhimin;YUAN Julin;Key Laboratory of Healthy Freshwater Aquaculture, Ministry of Agriculture and Rural Affairs, Key Laboratory of Fish Health and Nutrition of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries;Huzhou Normal Unversity;

ecological purification;;Micropterus salmoides;;earthy smell;;nutrient content;;fatty acid;;amino acid

Contents of geosmin(GSM)and 2-Methylisoborneol(2-MIB)and nutritional compositions including protein, fatty acids and amino acids were determined in largemouth bass(Micropterus salmoides)with body weight of 450 ～ 500 g farmed in a marketable fish ponds and then held in clean water for 0 d, 7 d, 14 d, 21 d and 28 d to evaluate the change in changes in contents of GSM and2-MIB earthy odor and nutritional compositions of largemouth bass in clean water and to explore its effect on the improvement of fish flesh quality. The contents of GSM and were shown to be already below the sensory threshold at the 7th day during the clean water holding process, with removal rates of 48.7% for GSM and 81.70% for 2-MIB. There was decrease in fat content and increase in protein content in the early stage, without significant change in moisture and ash content. The content of DHA was found to be increased and C18:1n-9 decreased significantly at the 7th day(P < 0.05), improving the nutritional value of fat acids. Total amount of amino acids, essential amino acids and delicious amino acids were shown to be an upward trend throughout the process, while the amino acid scores were not significantly changed(P > 0.05). In conclusion ecological clean water holding leads to effectively remove the earthy odor and the quality of fish flesh, with the optimal holding period of 7 days.