The safety of feed derived from genetically modified (GM) crops is one of the focuses of attention. To evaluate the ecotoxicological effects of transgenic mCry1Ac maize (BT799) on fish, zebrafish (Danio rerio) were fed extruded feeds containing either 20% GM maize (GMF) or its parental control maize (PF), GM maize meal (GMM) or its parental control maize meal (PMM), and a control commercial feed (CF), respectively. The growth performance, histopathology, reproduction, antioxidant enzyme activity and mRNA expression levels of sensitive protein in the liver were investigated over the course of a 98-day feeding trial. The results showed that transgenic mCry1Ac maize had no significant effect on growth, histopathology of the liver, brain and intestinal tract, fecundity, hatching rate of fertilized eggs, superoxide dismutase (SOD), catalase (CAT) activity, mRNA expression levels of SOD and CAT, or heat shock protein 70 (HSP70) and vitellogenin (VTG) in the liver. However, zebrafish fed the commercial feed exhibited significantly greater weight, longer length, and higher specific growth rate than those fed feeds (GMF and PF) and maize meals (GMM and PMM). The hatching rate of zebrafish in the feed groups was significantly lower than that of the maize meal groups and the commercial feed group. The mRNA transcriptional levels of VTG were significantly higher in the liver for the feed groups (3.85±0.76) than that for the maize meal groups (1.60±0.56). These results suggest that transgenic mCry1Ac maize has no ecotoxicological effects on zebrafish. However, the differences in nutrient composition and palatability between the extruded experimental feeds and the commercial feed would lead to significant diffe-rences in some parameters.
转基因作物的饲用安全性问题一直是人们关注的焦点之一.为评估转mCry1Ac基因玉米BT799对鱼类的生态毒理效应,本研究以斑马鱼为受试动物,设置5个处理:含20%转基因玉米膨化饲料组(GMF)、含20%亲本玉米膨化饲料组(PF)、转基因玉米粉(GMM)、亲本玉米粉(PMM)以及商业饲料对照组(CF),通过98 d的喂养试验,调查斑马鱼的生长表现、组织病理、繁殖、肝脏中抗氧化酶活性及敏感蛋白mRNA的表达水平.结果表明: 转mCry1Ac基因玉米对斑马鱼的各项生长指标、肝脏、脑和肠道的组织病理、产卵量、受精卵孵化率、肝脏中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,以及SOD、CAT、热激蛋白70(HSP70)和卵黄蛋白原(VTG)mRNA表达量均无显著影响.但在试验后期,饲料组(GMF和PF)和玉米粉组(GMM和PMM)斑马鱼的体重、体长和特定生长率显著低于商业饲料组;饲料组斑马鱼的孵化率显著低于玉米粉组和商业饲料组;饲料组(3.85±0.76)雄鱼肝脏中的VTG mRNA表达量显著高于玉米粉组(1.60±0.56).研究表明,转mCry1Ac基因玉米对斑马鱼没有明显生态毒理效应,但由于配制的膨化饲料与商业饲料在营养成分和适口性上的差异,可能导致个别指标与商业饲料组相比有显著差异.
Keywords: BT799; ecotoxicology; genetically modified maize; safety assessment of GM crops; zebrafish.