Soares T M, Coutinho D A, Lacerda L D, Moraes M O, Rebelo M F
Laboratório de Biogeoquímica Costeira, Instituto de Ciências do Mar, Universidade Federal do Ceará, Fortaleza, CE, Brazil, 60165-081.
Braz J Biol. 2011 Feb;71(1):131-7. doi: 10.1590/s1519-69842011000100019.
This study describes the accumulation of Hg and metallothionein gene expression in Litopenaeus vannamei Boone, 1931 with aquafeeds as the major source of Hg. Trials were conducted under controlled conditions in experimental tank facilities with high (indoor tanks) and low (outdoor tanks) Hg aquafeeds concentrations. Aquafeeds were the sole source of Hg for the shrimps and concentrations varied from 5.4 to 124 ng.g-1 d.w.. In the three animal fractions analysed; muscle (6,3 - 15,9 ng.g-1); hepatopancreas (5,1 - 22,0 ng.g-1) and exoskeleton (3,0 - 16,2 ng.g-1), Hg concentrations were significantly lower in the outdoor trials submitted to Hg-poor aquafeeds. Maximum shrimp muscle Hg concentrations were low (36.4 ng.g-1 w.w.) relative to maximum permissible concentrations for human consumption and Hg content in muscle and hepatopancreas were significantly correlated with Hg content in aquafeeds. Highest Hg concentrations in the exoskeleton of animals exposed to Hg-richer aquafeed, suggested that a detoxification mechanism is taking place. On the other hand the metallothionein suffered no variation in its relative expression in any of the experiments, meaning that the contact with feed containing the observed Hg concentrations were not sufficient to activate gene transcription. It was not possible, under the experimental design used, to infer Hg effects on the biological performance of the animals.
本研究描述了以水产饲料作为汞的主要来源时，凡纳滨对虾（Litopenaeus vannamei Boone，1931）体内汞的积累及金属硫蛋白基因的表达情况。试验在可控条件下，于汞含量高（室内水槽）和低（室外水槽）的水产饲料浓度的实验水槽设施中进行。水产饲料是虾类汞的唯一来源，其浓度在5.4至124纳克·克⁻¹干重之间变化。在所分析的三个动物组织部分中；肌肉（6.3 - 15.9纳克·克⁻¹）、肝胰腺（5.1 - 22.0纳克·克⁻¹）和外骨骼（3.0 - 16.2纳克·克⁻¹），在投喂低汞水产饲料的室外试验中，汞浓度显著较低。相对于人类消费的最大允许浓度，虾肌肉中的最大汞浓度较低（36.4纳克·克⁻¹湿重），并且肌肉和肝胰腺中的汞含量与水产饲料中的汞含量显著相关。暴露于汞含量较高的水产饲料的动物外骨骼中汞浓度最高，这表明正在发生解毒机制。另一方面，在任何实验中金属硫蛋白的相对表达均无变化，这意味着与含有观察到的汞浓度的饲料接触不足以激活基因转录。在所采用的实验设计下，无法推断汞对动物生物学性能的影响。
