The effects of the acetic acid “pain” test on feeding, swimming, and respiratory responses of rainbow trout (Oncorhynchus mykiss): A critique on Newby and Stevens (2008)—Response
About: This article is published in Applied Animal Behaviour Science.The article was published on 2009-01-15. It has received 8 citations till now. The article focuses on the topics: Rainbow trout.
Citations
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TL;DR: Overall, the behavioral and neurobiological evidence reviewed shows fish responses to nociceptive stimuli are limited and fishes are unlikely to experience pain.
Abstract: We review studies claiming that fish feel pain and find deficiencies in the methods used for pain identification, particularly for distinguishing unconscious detection of injurious stimuli (nociception) from conscious pain. Results were also frequently misinterpreted and not replicable, so claims that fish feel pain remain unsubstantiated. Comparable problems exist in studies of invertebrates. In contrast, an extensive literature involving surgeries with fishes shows normal feeding and activity immediately or soon after surgery. C fiber nociceptors, the most prevalent type in mammals and responsible for excruciating pain in humans, are rare in teleosts and absent in elasmobranchs studied to date. A-delta nociceptors, not yet found in elasmobranchs, but relatively common in teleosts, likely serve rapid, less noxious injury signaling, triggering escape and avoidance responses. Clearly, fishes have survived well without the full range of nociception typical of humans or other mammals, a circumstance according well with the absence of the specialized cortical regions necessary for pain in humans. We evaluate recent claims for consciousness in fishes, but find these claims lack adequate supporting evidence, neurological feasibility, or the likelihood that consciousness would be adaptive. Even if fishes were conscious, it is unwarranted to assume that they possess a human-like capacity for pain. Overall, the behavioral and neurobiological evidence reviewed shows fish responses to nociceptive stimuli are limited and fishes are unlikely to experience pain.
224 citations
Cites background or result from "The effects of the acetic acid “pai..."
...but some possible reasons were considered in subsequent discussion (Newby and Stevens 2009; Sneddon 2009)....
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...In addition, the morphine dosage used by Sneddon et al. (2003b) was exceedingly high (Newby et al. 2008; Newby and Stevens 2009)....
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...In a later communication on this point, Sneddon stated that the published dose was an error and the actual dose was 300 mg kg 1 (Newby and Stevens 2009), still a huge dose that exceeds the lethal dose in mammals (Votava and Horakova 1952)....
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...Newby and Stevens were not able to provide a definitive explanation for the differences in results between their study and those of Sneddon et al. but some possible reasons were considered in subsequent discussion (Newby and Stevens 2009; Sneddon 2009)....
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TL;DR: In this article, the authors revisited the evidence attributing sentience-pain-suffering to aquatic animals and summarized the research used to support the regulations governing the welfare of aquatic animals, particularly its limitations.
Abstract: We revisit the evidence attributing sentience-pain-suffering to aquatic animals. The objective is to inform readers of the current state of affairs, to direct attention to where research is needed, and to identify “wicked” questions that are difficult to resolve unequivocally. By separating the ethical from the scientific debate, applying organized skepticism to the latter, and taking a pragmatic approach that does not depend on resolving the “wicked” questions, we hope to focus and strengthen research on aquatic animal welfare. A second but closely-related objective is to briefly summarize the research used to support the regulations governing the welfare of aquatic animals, particularly its limitations. If you interact with aquatic animals, these regulations already affect you. If the regulatory environment continues on its current trajectory (adding more aquatic animal taxa to those already regulated), activity in some sectors could be severely restricted, even banned. There are surely some lively debates and tough choices ahead. In the end, extending legal protection to aquatic animals is a societal choice, but that choice should not be ascribed to strong support from a body of research that does not yet exist, and may never exist, and the consequences of making that decision must be carefully weighed.
72 citations
TL;DR: Zebrafish (Danio rerio) is proposed as a novel short-term behavioral model of nociception and its sensitivity and robustness are analyzed to suggest that a change in behavioral responses of zebrafish to acetic acid is a reasonable model to test analgesics.
Abstract: Pain is a major symptom in many medical conditions, and often interferes significantly with a person's quality of life. Although a priority topic in medical research for many years, there are still few analgesic drugs approved for clinical use. One reason is the lack of appropriate animal models that faithfully represent relevant hallmarks associated with human pain. Here we propose zebrafish (Danio rerio) as a novel short-term behavioral model of nociception, and analyse its sensitivity and robustness. Firstly, we injected two different doses of acetic acid as the noxious stimulus. We studied individual locomotor responses of fish to a threshold level of nociception using two recording systems: a video tracking system and an electric biosensor (the MOBS system). We showed that an injection dose of 10% acetic acid resulted in a change in behavior that could be used to study nociception. Secondly, we validated our behavioral model by investigating the effect of the analgesic morphine. In time-course studies, first we looked at the dose-response relationship of morphine and then tested whether the effect of morphine could be modulated by naloxone, an opioid antagonist. Our results suggest that a change in behavioral responses of zebrafish to acetic acid is a reasonable model to test analgesics. The response scales with stimulus intensity, is attenuated by morphine, and the analgesic effect of morphine is blocked with naloxone. The change in behavior of zebrafish associated with the noxious stimulus can be monitored with an electric biosensor that measures changes in water impedance.
64 citations
Cites background or methods from "The effects of the acetic acid “pai..."
...As a result of these observations, teleost fish have been used as models for pain and analgesia research [10,12-15]....
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...However, only few fish species have been used to test the efficacy of opioids and non-opioids [12,14-16]....
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TL;DR: It is argued that, as long as fishing and handling practices are as fish friendly as possible, most animal welfare perspectives can easily accommodate recreational fishing in its present form, and animal liberation and animal rights philosophies tend to reject recreational fishing.
Abstract: In some industrialized countries, recreational fishing has come under moral pressure. To understand potential ramifications, we first describe three dominant philosophies of human-animal interactions (i.e., animal welfare, animal liberation, and animal rights). We contend that, as long as fishing and handling practices are as fish friendly as possible, most animal welfare perspectives can easily accommodate recreational fishing in its present form. In contrast, animal liberation and animal rights philosophies tend to reject recreational fishing. On the hypothesis that economic development is conducive to the emergence of pro-animal values in the wider public, it can be assumed that anti-angling sentiments resonating strongly with animal liberation/rights thinking might increase. Examples from opinion surveys covering a range of countries show that about 25% of people already morally question recreational fishing for sport. Coupled with the supposed shift in pro-animal values, this public sentimen...
55 citations
TL;DR: It is indicated that tricaine has no effect on several commonly used behavioural parameters, and that it may be unnecessary to postpone behavioural observations to 30 min after anaesthesia.
Abstract: The pros and cons of using anaesthesia when handling fish in connection with experiments are debated. A widely adopted practice is to wait thirty minutes after anaesthesia before behavioural observations are initiated, but information about immediate effects of a treatment is then lost. This is pertinent for responses to acute stressors, such as acid injection in the acetic acid pain test. However, omission of anaesthetics in order to obtain data on immediate responses will compromise the welfare of fish and contribute to experimental noise due to stress. We therefore tested the effect of tricaine methanesulfonate on the behaviour of zebrafish. We predicted that tricaine (MS 222) would decrease swimming velocity and that the control fish would show an increased level of anxiety- and stress-related behaviours compared to the tricaine group. Following acclimatization to the test tank, baseline behaviour was recorded before immersion in either tricaine (168 mg l(-1), treatment group, N = 8) or tank water (control group, N = 7). Latencies to lose equilibrium and to lose response to touch were registered. The fish was then returned to the test tank, and the latency to regain equilibrium was registered in anaesthetized fish. When equilibrium was regained, and at five, thirty and sixty minutes after the fish had been returned to the test tank, behaviour was recorded. The tricaine fish showed the following responses (mean ± sd): latency to lose equilibrium 22.6 s±3.9; latency to lose response to touch 101.9 s±26.8; latency to regain equilibrium 92.0 s±54.4. Contrary to our predictions, neither treatment caused a change in any of the behaviours registered. This indicates that tricaine has no effect on several commonly used behavioural parameters, and that it may be unnecessary to postpone behavioural observations to 30 min after anaesthesia.
47 citations
References
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TL;DR: This review attempts to delineate common themes on the physiological and metabolic roles of cortisol in teleost fishes and to suggest new approaches that might overcome some of the inconsistencies on the role of this multifaceted hormone.
Abstract: Cortisol is the principal corticosteriod in teleost fishes and its plasma concentrations rise dramatically during stress. The relationship between this cortisol increase and its metabolic consequences are subject to extensive debate. Much of this debate arises from the different responses of the many species used, the diversity of approaches to manipulate cortisol levels, and the sampling techniques and duration. Given the extreme differences in experimental approach, it is not surprising that inconsistencies exist within the literature. This review attempts to delineate common themes on the physiological and metabolic roles of cortisol in teleost fishes and to suggest new approaches that might overcome some of the inconsistencies on the role of this multifaceted hormone. We detail the dynamics of cortisol, especially the exogenous and endogenous factors modulating production, clearance and tissue availability of the hormone. We focus on the mechanisms of action, the biochemical and physiological impact, and the interaction with other hormones so as to provide a conceptual framework for cortisol under resting and/or stressed states. Interpretation of interactions between cortisol and other glucoregulatory hormones is hampered by the absence of adequate hormone quantification, resulting in correlative rather than causal relationships.
2,139 citations
Journal Article•
TL;DR: It is concluded that although the neural basis of the most used tests is poorly understood, their use will be more profitable if pain is considered within, rather than apart from, the body's homeostatic mechanisms.
Abstract: The study of pain in awake animals raises ethical, philosophical, and technical problems. We review the ethical standards for studying pain in animals and emphasize that there are scientific as well as moral reasons for keeping to them. Philosophically, there is the problem that pain cannot be monitored directly in animals but can only be estimated by examining their responses to nociceptive stimuli; however, such responses do not necessarily mean that there is a concomitant sensation. The types of nociceptive stimuli (electrical, thermal, mechanical, or chemical) that have been used in different pain models are reviewed with the conclusion that none is ideal, although chemical stimuli probably most closely mimic acute clinical pain. The monitored reactions are almost always motor responses ranging from spinal reflexes to complex behaviors. Most have the weakness that they may be associated with, or modulated by, other physiological functions. The main tests are critically reviewed in terms of their sensitivity, specificity, and predictiveness. Weaknesses are highlighted, including 1) that in most tests responses are monitored around a nociceptive threshold, whereas clinical pain is almost always more severe; 2) differences in the fashion whereby responses are evoked from healthy and inflamed tissues; and 3) problems in assessing threshold responses to stimuli, which continue to increase in intensity. It is concluded that although the neural basis of the most used tests is poorly understood, their use will be more profitable if pain is considered within, rather than apart from, the body's homeostatic mechanisms.
1,929 citations
TL;DR: The data provide evidence that a stressor-specific activation of the BSC and BPI axes may occur in Sparus aurata, and conclude that air exposure mainly activates the brain-sympathetic-chromaffin cell (BSC) axis.
Abstract: We investigated short-term eVects (up to 24 h) of air exposure and confinement, and long-term eVects (up to 11 days) of confinement, to elucidate signalling pathways in the stress response of gilthead sea bream Sparus aurata L. Plasma glucose and lactate were taken as indicators of sympathetic activation, and AE-melanocyte stimulating hormone (AE-MSH), adrenocorticotrophic hormone (ACTH) and cortisol as indicators of activation of the brain‐ pituitary‐interrenal (BPI) axis. Air exposure for 3 min resulted, within 30 min, in an increase in plasma concentrations of cortisol, AE-MSH, glucose, lactate, osmolality and plasma Na, Cl and Mg. Plasma ACTH and ‚-endorphin and plasma K, Ca and P did not change. We conclude that air exposure mainly activates the brain‐ sympathetic‐chromaYn cell (BSC) axis. In fish confined at a density of 70 kg/m 3 (compared with 4 kg/m 3 in controls), cortisol, ACTH and AE-MSH increased within 1 h, indicating activation of the BPI axis. Plasma glucose, Na, Cl and Mg increased with an 8 h delay compared with the response to air exposure. No changes in plasma lactate, osmolality, K, Ca and P were observed. Long-term confinement induced a biphasic cortisol response with peaks at 1 h and at 2 and 3 days. A gradual increase in plasma ‚-endorphin concentrations peaked at 7 days; the concentration of AE-MSH increased rapidly within 1 h and then declined to control values 4 days after the onset of confinement. No changes in ACTH were detected. Our data provide evidence that a stressor-specific activation of the BSC and BPI axes may occur in Sparus aurata.
328 citations
TL;DR: Assessing the acute effects of administering a noxious chemical to the lips of rainbow trout concluded that these pain-related behaviours are not simple reflexes and therefore there is the potential for pain perception in fish.
316 citations
TL;DR: Results suggest that nociception captures the animal's attention with only a relatively small amount of attention directed at responding to the fear of the novel object.
217 citations