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Dysmorphology and Locomotor Activity Assessment in Larval Zebrafish (Danio rerio)
Citation:
Hedge, J., M. Waalkes, D. Korest, B. Hill, K. Jarema, D. Hunter, AND S. Padilla. Dysmorphology and Locomotor Activity Assessment in Larval Zebrafish (Danio rerio). Aquaculture America 2020, Honolulu, Hawaii, February 09 - 12, 2020. https://doi.org/10.23645/epacomptox.12685565
Impact/Purpose:
The US EPA has been evaluating higher throughput non-mammalian behavior testing methods, including zebrafish larvae, to screen and prioritize chemicals for developmental neurotoxicology. Careful consideration of intrinsic and extrinsic confounders of studies that can influence results of such studies is essential. Morphological assessment is one such intrinsic confounder that could have dramatic effects on behavior yet is rarely addressed adequately if at all in publications. The results of this study illustrate the importance of morphological assessment and reporting with locomotor behavior testing using zebrafish larvae because variables such as swim bladder inflation or minor dysmorphology could have profound effects on locomotor activity which could greatly confound the study results. There are many such intrinsic and extrinsic factors that can affect the results of chemical exposures which should be monitored, reported, and controlled for sound science.
Description:
Presenter: Joan Hedge Title: Dysmorphology and Locomotor Activity Assessment in Larval Zebrafish (Danio rerio) Authors: Joan M. Hedge1, Matthew R. Waalkes2, David Korest2, Bridgett Hill2, Kimberly Jarema3, Deborah L. Hunter1, and Stephanie Padilla1 Affiliations: US EPA, Office of Research and Development, Center for Computational Toxicology and Exposure1; ORISE2; Center for Public Health and Environmental Assessment3; Research Triangle Park, NC Abstract: To screen and prioritize chemicals for developmental neurotoxicology, the US EPA is evaluating higher throughput, non-mammalian behavior testing methods using zebrafish larvae. Careful consideration of intrinsic and extrinsic experimental confounders is essential to the development of robust and reliable screening approaches as these confounders can affect the results of chemical exposures. Morphological assessment is one such confounder that could have dramatic effects on behavior yet is rarely addressed adequately in publications. In the present study, approximately 1600 control zebrafish larvae were examined. On day 6 of development, larval behavior was assessed using a 40 minutes light and dark phase locomotor test. After testing, larvae were immediately assessed for dysmorphology (e.g., edema, spinal curvature and swim bladder non-inflation). Results demonstrate that normal larvae with inflated swim bladders showed 3X more activity in the light phase as normal larvae with uninflated swim bladders, showing that swim bladder status profoundly affects activity. Conversely, when comparing normal larvae with uninflated swim bladders versus abnormal larvae with uninflated swim bladders, normal larvae with uninflated swim bladders showed 4.5X more activity as abnormal larvae with uninflated swim bladders, demonstrating dysmorphology itself affects behavior. These results illustrate the importance of morphological assessment and reporting in zebrafish larval locomotor behavior testing, because variables such as swim bladder inflation status or minor dysmorphology have profound effects on locomotor activity. This abstract does not necessarily reflect official USEPA policy.
URLs/Downloads:
DOI: Dysmorphology and Locomotor Activity Assessment in Larval Zebrafish (Danio rerio)
HEDGE AQUACULTURE AMERICA ZHA SESSION 2020 PRESENTATION.PDF (PDF, NA pp, 5087.519 KB, about PDF)