不同饲料对乌鳢中汞和甲基汞富集水平的影响

为了解冰鲜鱼和水产配合饲料2种不同饲料对乌鳢(Ophiocephalus argus)中汞和甲基汞富集水平和食用安全的影响,实验采用ICP-MS法、液相-原子荧光分光光度法分别测定乌鳢在摄食冰鲜鱼和水产配合饲料两种不同饲料后,研究其肌肉、肝脏和肾脏3种不同组织中总汞和甲基汞的含量随养殖周期的富集规律。结果显示:在整个养殖过程中,饲料投喂组肌肉、肝脏和肾脏中总汞和甲基汞含量均低于冰鲜鱼投喂组,其中冰鲜鱼组肌肉、肝脏中总汞和甲基汞的富集均明显高于饲料组,肾脏中总汞的富集明显高于饲料组。从不同组织看,肌肉对总汞和甲基汞的富集显著高于肝脏和肾脏。肌肉中汞主要以甲基汞形式存在,平均含量占总汞的84.2%,低于国家食品安全限量标准,食用风险较低。相关性分析显示,2种不同饲料中总汞、甲基汞含量对乌鳢生长周期内总汞、甲基汞富集无显著性影响。结果表明乌鳢配合饲料养殖较冰鲜鱼养殖更为安全,适宜进一步推广运用。

Effects of different feeds on accumulative levels of total mercury and methyl mercury in Ophiocephalus argus

This experiment was conducted to study the effects of frozen fish(TF)and formulated diet(FF)on growth,heavy metal accumulation and food safety of Ophiocephalus argus.Two farms located in Huzhou City were selected to breed O.argus,which fed with TF and FF,respectively.The contents of total mercury(Hg)and methyl mercury(MeHg)in the tissue of muscle,liver and kidney were investigated with the method of inductively coupled plasma mass spectrometry(ICP-MS)and high-performance liquid chromatography-atomic fluorescence spectrometry(LC-AFS).Then the variation of Hg and MeHg with growth cycle were analysed.Results showed that the contents of Hg and MeHg in FF group were lower than TF group among with muscle,liver and kidney tissues.It was showed that TF group has an apparently higher concentration level of Hg and MeHg in muscle and liver tissues than the FF group,while the concentration of Hg in kidney tissues in TF group was significantly higher than the FF group.Different tissues had different enrichment levels,the enrichment of Hg and MeHg in muscle was significantly higher than that in the liver and kidney.The mercury in muscle mainly existed in the form of MeHg,with the average content accounting for 84.2%of Hg,which was lower than the national food safety limited standard,so the food safety risk of O.argus was low.Besides,correlational analyses indicated that the contents of Hg and MeHg in two kinds of feeds(frozen fish and formulated diet)both had no significant effect on the enrichment of Hg and MeHg in the growth cycle.Consequently,it was recommended that breeding O.argus with a formulated diet was safer than frozen fish and this culture patternalways worthy of further research,application and promotion.