Arabian killifish (Aphanius dispar) embryos: A model organism for the risk assessment of the Arabian Gulf coastal waters

Abstract

Fish embryos are excellent models for studies aimed at understanding toxic mechanisms and indications of possible acute and chronic effects. For the past 3 yr, an Arabian killifish (Aphanius dispar) fish embryo test has been developed in the authors' laboratory as a routine ecotoxicological test that can be used to support risk assessment of potential contaminants in Arabian Gulf coastal waters. Tests were conducted with 3 reference toxicants (3,4-dichloroaniline [DCA], sodium dodecyl sulfate, and zinc sulfate [Zn]) and chlorine, a disinfectant used widely in industrial cooling systems around the Arabian Gulf region. The 50% effect concentration (EC50) for DCA was 0.47 mg/L and 1.89 mg/L for embryos exposed before 6 hpf and after 168 hpf, respectively. Sublethal effects were mainly observed at concentrations above 2.5 mg/L, the effects included severe pericardial edema and tail shortage. The sodium dodecyl sulfate ionic surfactant caused mortality at both early and late stages of embryo development; it caused coagulation, severe deformity, and hemolysis. Both the EC50 and the 50% lethal concentration (LC50) for sodium dodecyl sulfate were 9.37 mg/L. Salinity influenced the toxicity of Zn to killifish embryos: at 40 psu Zn was found not to be toxic, whereas at 20 psu toxicity had increased significantly (p < 0.05). Values of EC50 and LC50 were 2.5 mg/L and 4 mg/L, respectively. Concentrations above 15 mg/L in embryos were often accompanied by upper abdominal edema and inhibition of growth, especially evident in the tail. Chlorine caused mortality at a lower concentration; for example, at 0.05 mg/L 33% of embryos were found dead at the end of the experiment. The LC50 for chlorine was determined to be 0.08 mg/L. Examination of the existing literature showed similar results to the present study's findings. The results suggest a more comparable sensitivity of killifish embryos to that of other fish embryo test recommended species. The present study's findings support the ability of killifish to be an indicator organism for environmental risk assessments of Arabian Gulf waters. Benefits include sensitivity to a wide range of substances and conditions, animal alternative, ease of fish breeding, and clarity of the embryos.

Comparative embryotoxicity and genotoxicity of the herbicide diuron and its metabolites in early life stages of Crassostrea gigas: Implication of reactive oxygen species production

“…However, toxic and embryotoxic effects reported in fish for 3,4-DCA are observed at concentrations nearly one order of magnitude higher than those tested in the present study. For fish embryotoxicity assay, EC50 values are in the range of mg.L -1 (Zhu et al 2013;Saeed et al 2015), e.g., around 6 mg.L -1 in the zebrafish (Braunbeck & Lammer 2006). In crucian carp, Li et al (2003) showed that 3,4-DCA triggered necrosis and degenerative lesions in liver that could be due to oxidative stress and lipid peroxidation from the concentration of 0.2 mg.L -1 .…”

Early embryonic development of brackish water Killifish Aphanius hormuzensis (Teleostei, Aphaniidae) inhabiting coastal environment in Southern Iran

“…It is a secondary freshwater fish and is well known for its remarkable capacity to adapt to different ecological conditions (Teimori et al., ). Thus, it is generally an attractive model to be studied for different aspects including the understanding of ecological plasticity, evolutionary processes, environmental studies, histopathological changes and recently regeneration capacity (Ferrito et al., ; Iranmanesh & Motamedi, ; Motamedi, Shamsaldini, Teimori, & Askari Hesni, ; Parenti, ; Saeed, Al‐Naema, Butler, & Febbo, ; Teimori et al., ; Tigano et al., ; Wildekamp, Kücük, Ünlüsayin, & Neer, ; Zeinali & Motamedi, ).…”

Histomicroscopy and normal anatomy of the adult killifishAphanius hormuzensis(Teleostei; Aphaniidae) from the Persian Gulf coastal environment

“…Beside this standard biological model, the members of killifishes (Cyprinodontiformes) have also been used successfully in different biological studies. Examples are Nothobranchius furzeri Jubb, 1971 for studies on aging (Genade et al, ; Terzibasi et al, ; Wendler et al, ) or Aphanius dispar (Rüppell, 1829) for the assessment of environmental pollution (Saeed, Al‐Naema, Butler, & Febbo, ).…”

“…They would be good candidates in order to eliminate mosquito larvae from the environments and consequently to remove the mosquito borne diseases such as dengue, and rift valley fever (Al‐Akel & Suliman, ). In addition, the embryo of Aphanius has been used as model in ecotoxicological tests for risk assessment of potential contaminants in coastal waters (Saeed et al, ). Also, the Mediterranean species of Aphanius (known as A. fasciatus ) has been used as excellent monitoring species for the analysis of environmental impact on the coastal Mediterranean regions (Kessabi et al, ).…”

“…In addition, the embryo of Aphanius has been used as model in ecotoxicological tests for risk assessment of potential contaminants in coastal waters (Saeed et al, 2015). Also, the Mediterranean species of Aphanius (known as A. fasciatus) has been used as excellent monitoring species for the analysis of environmental impact on the coastal Mediterranean regions (Kessabi et al, 2012).…”