Dying for change: A roadmap to refine the fish acute toxicity test after 40 years of applying a lethal endpoint

Katsiadaki, Ioanna; Ellis, Tim; Andersen, Linda; Antczak, Philipp; Blaker, Ellen; Burden, Natalie; Fisher, T. L.; Green, Christopher; Labram, Briony; Pearson, Audrey; Petersen, Karen Koefoed; Pickford, Daniel B.; Ramsden, Chris; Rønneseth, Anita; Ryder, Kathryn; Sacker, Dominic; Stevens, Chloe; Watanabe, Haruna; Yamamoto, Hiroshi; Sewell, Fiona; Hawkins, Penny; Rufli, Hans; Handy, Richard D.; Maynard, Samuel K.; Jacobs, Miriam N.

doi:10.1016/j.ecoenv.2021.112585

Cited by 15 publications

(8 citation statements)

References 39 publications

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“…In acute toxicity tests conducted with fish, it is difficult to use the moribund state as an endpoint because there is no consensus about which sublethal signs indicate the moribund state or are predictive of transition to imminent death (Dan et al, 2017; Drummond et al, 1986; Midtlyng et al, 2011; Rufli, 2012). To enable definition of the moribund state in fish, the association between the various clinical signs and imminent death must be determined (Katsiadaki et al, 2021; OECD, 2019). There is also concern that LC50 values derived from using the moribund state as an endpoint may differ from those derived from using the conventional endpoint of death.…”

Section: Introductionmentioning

confidence: 99%

“…A United Kingdom-based workshop to discuss how test guideline 203 can be refined summarized the refinement opportunities for test guideline 203 in a realistic roadmap (Katsiadaki et al, 2021). This workshop also described that the most efficient way of linking clinical signs to mortality is to perform the test and record clinical signs and continue until mortality is reached at the end of the test (Katsiadaki et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…However, the five moribund stages used in that analysis were defined based on four symptoms, swimming behavior, loss of equilibrium, ventilation, and discoloration; and there remain uncertainties between these sublethal effects and mortality (Rufli, 2012; Dan et al, 2017). A United Kingdom‐based workshop to discuss how test guideline 203 can be refined summarized the refinement opportunities for test guideline 203 in a realistic roadmap (Katsiadaki et al, 2021). This workshop also described that the most efficient way of linking clinical signs to mortality is to perform the test and record clinical signs and continue until mortality is reached at the end of the test (Katsiadaki et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Severity Classification of Clinical Signs and Defining the Moribund State as an Experimental Endpoint for Acute Toxicity Testing Using Japanese Medaka (Oryzias latipes)

Yamagishi

Kawano

Watanabe

et al. 2022

Enviro Toxic and Chemistry

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Use of the moribund state as an endpoint for acute toxicity testing in fish is complicated by the lack of consensus about the sublethal signs that define the state or that can predict imminent death. Defining the moribund state in fish requires determination of the association between each observable sublethal sign and transition to imminent death. To establish a criterion for defining the moribund state in Japanese medaka (Oryzias latipes), we determined death/clinical‐sign ratios, defined as the proportion of fish with each clinical sign that transitioned to imminent death, for 13 clinical signs observed in individually housed fish exposed to one of two typical toxicants, three pharmaceuticals, two pesticides, and one metal. Also, the time from onset of each clinical sign to transition to imminent death (referred to as the survival time) was determined by continuous monitoring. Three of the observed clinical signs—immobility, lethargy, and immobility at the surface—were found to be indicators of the moribund state, with each of these signs having a death/clinical‐sign ratio of 1.0. Evaluation of the survival time after onset of the other 10 signs enabled determination of whether timely euthanasia would be appropriate, thereby providing a means of reducing the suffering of laboratory fish in the period before death. Environ Toxicol Chem 2022;41:1089–1095. © 2022 SETAC

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Severity Classification of Clinical Signs and Defining the Moribund State as an Experimental Endpoint for Acute Toxicity Testing Using Japanese Medaka (Oryzias latipes)

Yamagishi

Kawano

Watanabe

et al. 2022

Enviro Toxic and Chemistry

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“…While collecting and analyzing tissues or blood samples from animals exposed to test chemicals can provide valuable insights into the molecular mechanisms of toxicity, this process can also cause harm or death to the animals. In light of increasing concern for animal welfare and ethical issues, some countries have introduced regulations that encourage or require the reduction of animal use, replacement with alternative methods, and refinement of testing procedures to avoid painful or distressing situations (Katsiadaki et al 2021;Paparella et al 2021;Yamagishi et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Environmental RNA as a non-invasive tool for assessing toxic effects in fish: a proof-of-concept study using Japanese medaka exposed to pyrene

Hiki

Yamagishi

Yamamoto

2023

Preprint

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Although environmental RNA (eRNA) is emerging as a non-invasive tool to assess the health status of aquatic macro-organisms, the potential of eRNA remains largely untested. In this study, we investigated the ability of eRNA to detect changes in gene expression in Japanese medaka fish (Oryzias latipes) in response to sub-lethal pyrene exposure, as a model toxic chemical. We performed standardized acute toxicity tests and collected eRNA from tank water and RNA from fish tissue after 96 h of exposure. Our results showed that over 1000 genes were detected in eRNA and the sequenced read counts of these genes correlated with those in fish tissue (r = 0.50). Moreover, eRNA detected 86 differentially expressed genes in response to pyrene, some of which were shared by fish RNA, including suppression of collagen fiber genes. These results suggest that eRNA has the potential to detect changes in gene expression in fish in response to environmental stressors without the need for sacrificing or causing pain to fish. However, we also found that the majority of sequenced reads of eRNA (> 99%) were not mapped to the reference medaka genome and they originated from bacteria and fungi, resulting in low sequencing-depth. In addition, eRNA, in particular nuclear genes, was highly degraded with a median transcript integrity number (TIN) of < 20. These limitations highlight the need for future studies to improve the analytical methods of eRNA application.

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“…These principles are a refinement since the next (higher) concentration/dose level need not be performed (also reducing animal use). More recently, work has begun to standardize recording of sublethal clinical signs of toxicity in fish, aiming to move away from LD 50 and mortality as the endpoint for acute fish studies (OECD TG 203; [ 4 , 15 ]).…”

Section: Introductionmentioning

confidence: 99%

Refining Procedures within Regulatory Toxicology Studies: Improving Animal Welfare and Data

Prior

Blunt²,

Crossman³

et al. 2021

Animals

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During the development of potential new medicines or agrochemicals, an assessment of the safety profile to humans and environmental species is conducted using a range of different in silico and in vitro techniques in conjunction with metabolism and toxicity studies using animals. The required studies are outlined within international regulatory guidelines which acknowledge and support the application of the 3Rs to reduce the number of animals used or to refine the procedures performed when these studies are deemed to be necessary. The continued development of new technologies and adoption of best-practice approaches to laboratory animal housing and study procedures has generated a series of refinements that can be incorporated into animal studies throughout the package. These refinements benefit the welfare of fish, mice, rats, rabbits, dogs, minipigs, and non-human primates (NHPs) whilst maintaining or improving data quality within general toxicology, metabolism, and other studies and can also bring efficiencies to processes that benefit study costs and timings. Examples are shared which cover the following topics: social housing of dogs and NHPs, surgical refinements in the rat bile duct cannulation model for collection of data for metabolism studies, whether fasting is really required prior to clinical pathology sampling, and the use of microsampling for toxicokinetics.

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Dying for change: A roadmap to refine the fish acute toxicity test after 40 years of applying a lethal endpoint

Cited by 15 publications

References 39 publications

Severity Classification of Clinical Signs and Defining the Moribund State as an Experimental Endpoint for Acute Toxicity Testing Using Japanese Medaka (Oryzias latipes)

Severity Classification of Clinical Signs and Defining the Moribund State as an Experimental Endpoint for Acute Toxicity Testing Using Japanese Medaka (Oryzias latipes)

Environmental RNA as a non-invasive tool for assessing toxic effects in fish: a proof-of-concept study using Japanese medaka exposed to pyrene

Refining Procedures within Regulatory Toxicology Studies: Improving Animal Welfare and Data

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