| 阳澄西湖水质与鲢土腥异味相关性研究 |
| Effect of Water Quality on Earthy-musty Off-flavor in Hypophthalmichthys molitrix from Yangcheng West Lake |
| 投稿时间：2014-10-11 修订日期：2014-12-05 |
| DOI：10.15928/j.1674-3075.2015.02.014 |
| 中文关键词:土腥异味 水质 鲢 阳澄西湖 |
| 英文关键词:muddy off-flavor (earth-musty off-flavor) water quality Hypophthalmichthys molitrix Yangcheng West Lake |
| 基金项目:国家自然科学基金项目（31272671)；苏州市相城区阳澄西湖专项项目。 |
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| 中文摘要: |
| 为揭示富营养湖泊水质对养殖鱼类土腥异味的影响，探究土腥异味的净化规律，在阳澄西湖设置了6个网围养殖区（A～F），面积分别为167、453、567、190、1000、400 hm2，于2009年初开始陆续放养鲢（Hypophthalmichthys molitrix）等养殖品种，次年春节前后捕捞并补放鱼种。2009－2011年连续3年跟踪监测了各围养区的总氮（TN）、总磷（TP)、化学耗氧量（CODMn）、叶绿素a（Chl-a）浓度，2012年5月从各围养区分别取鲢10尾，分析其肌肉中土臭味素（GSM） 和2-甲基异茨醇（2-MIB）含量，另从土腥异味较重的网围中取70尾鲢在清水中净化，并于净化后不同时间监测其肌肉中GSM和2-MIB含量。结果表明，阳澄西湖水质总体处于劣Ⅴ类，但Chl-a浓度在蓝藻水华阈值以下；网围养殖的鲢肌肉中GSM和2-MIB含量较高，且与TN、TP、Chl-a浓度均显著正相关。经过8 d净化，鲢肌肉中GSM和2-MIB浓度分别下降了55%和72%，经过32 d净化，GSM和2-MIB含量低于检出限。阳澄西湖围养滤食性鱼类有效控制了蓝藻水华的发生，表明鱼体的土腥异味与水质有关，可通过32 d的净化，消除鲢的土腥异味。 |
| 英文摘要: |
| Silver carp and bighead carp can suppress the occurrence of algae bloom by filter feeding plankton. However, the production of these species in eutrophic water body is hampered by the problem of a muddy off-flavor that profoundly affects consumer acceptance and commodity value. A recent study has identified the main substances responsible for the muddy off-flavor are geosmin (GSM) and 2-methylisoborneol (2-MIB). In this investigation we determined GSM and 2-MIB in silver carp farmed in Yangcheng West Lake in Suzhou City, Jiangsu Province and monitored the water quality parameters of the lake to study the relationship of the muddy off-flavor with water quality. A depuration trial was also carried out to assess the effectiveness of the process for removal of the off-flavor. Six enclosures (A-F) were set in Yangcheng West Lake with respective areas of 167, 453, 567, 190, 1000 and 400 hm2. The fry of silver carp (Hypophthalmichthys molitrix), bighead carp and other species fish were cultured together in the enclosures from the beginning of 2009. The fish were harvested near to Spring Festival of the next year and new fry were subsequently added to the enclosures. Total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (CODMn) and Chlorophyll a (Chl-a) were monitored in each enclosure from April, 2009 to November, 2011. Ten silver carp were sampled from each enclosure in May 2012 and the level of GSM and 2-MIB in muscle tissue were determined. Seventy silver carp (about 1.0 kg each) were caught from enclosure A (with the lowest water quality) for depuration trials. Five silver carps were placed in each water tank（140 cm×100 cm×70 cm）with tap water and aerated continually. The water was changed daily and the trial lasted 32 days, from May 29th to June 29th of 2012. At 0, 1, 2, 4, 8, 16, 32 d of the depuration period, nine silver carps were randomly selected and GSM and 2-MIB were determined. Average concentrations of TN, TP, CODMn from 2009 to 2011 were 2.80, 0.23, 6.01 mg/L and the concentration of Chl-a was 34.4 μg/L, indicating that water quality in Yangcheng West Lake was lower than Grade V, while the concentration of Chl-a was below the threshold for algae blooms. The concentrations of GSM and 2-MIB in muscle tissue of silver carp were high, with maximum values both occurring in enclosure A (7.98 μg/kg; 7.28 μg/kg) and minimum values both in enclosure C (5.27 μg/kg; 4.53 μg/kg). Muscle concentrations of GSM and 2-MIB were positively correlated with concentrations of TN, TP and Chl-a in the lake water. The concentrations of GSM and 2-MIB were reduced by 55% and 72% after eight days of depuration. After 32 days of depuration, concentrations of GSM and 2-MIB in silver carp were below detectable levels. Results suggest that algae blooms were controlled by releasing filter-feeding fish in Yangcheng West Lake. The muddy off-flavor of silver carps was related with water quality but can be removed by 32 days of depuration. |
| 朱健明,蔡春芳,杨超,叶元土,龚宏伟,张倩,吴韬,李婷,王泉林.2015.阳澄西湖水质与鲢土腥异味相关性研究[J].水生态学杂志,36(2):88-94. |
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