AALAS Webinar - Fish Welfare and Analgesia

Fish welfare is still a relatively new field. As such, regulations and protocols to ensure fish welfare are currently limited and vary considerable in different jurisdictions. This is in part because of the ongoing controversy as to whether fish feel pain. Potential solutions, such as pursuing clinically applicable research to increase knowledge of fishes' behavior and physiology, will be presented. This type of research would then lead to improved studies that could help to determine if and when analgesic drugs can be beneficial in fish, as they are in many other species. The use of analgesics in fish is still limited, partly because of the debate, but also because of the current lack of validated approach to assess pain in fish which limits out ability to evaluate the efficacy of analgesics in fish. Some recommendations on the use of analgesics in fish are currently in the literature; however, information on the properties of analgesic drugs in most fish species is still scarce and sometimes misleading. This presentation will review the available information on the use of analgesics in fish to help clinicians make an informed decision as to which drug and dose to use. The main agents that have been investigated are opioids, NSAID, and local anesthetics, primarily in rainbow trout and zebrafish. There is presently no overwhelming evidence of efficacy for most analgesics in fish, although beneficial effects on behavior and physiologic parameters have been reported in many instances, especially with morphine administration. Furthermore, most analgesics did not result in significant adverse side effects. Thus, analgesics could be administered whenever it is considered that an animal might experience pain, given that the drugs appear not to cause harm and may be beneficial. However, caution must be advised because 1) important interspecies variation has been reported and 2) unforeseen effects could affect experimental results.