Veterinary Medicine Commons^™

Clinical Anesthesia And Analgesia In Fish, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Fish have become a popular experimental model and companion animal, and are also farmed and caught for food. Thus, surgical and invasive procedures in this animal group are common, and this review will focus on the anesthesia and analgesia of fish. A variety of anesthetic agents are commonly applied to fish via immersion. Correct dosing can result in effective anesthesia for acute procedures as well as loss of consciousness for surgical interventions. Dose and anesthetic agent vary between species of fish and are further confounded by a variety of physiological parameters (e.g., body weight, physiological stress) as well as environmental …

Characterisation Of Chemosensory Trigeminal Receptors In The Rainbow Trout, Oncorhynchus Mykiss: Responses To Chemical Irritants And Carbon Dioxide, Jessica J. Mettam, Catherine R. Mccrohan, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Trigeminally innervated, mechanically sensitive chemoreceptors (M) were previously identified in rainbow trout, Oncorhynchus mykiss, but it is not known whether these receptors are responsive only to noxious, chemical irritants or have a general chemosensory function. This study aimed to characterise the stimulus–response properties of these receptors in comparison with polymodal nociceptors (P). Both P and M gave similar response profiles to acetic acid concentrations. The electrophysiological properties were similar between the two different afferent types. To determine whether the receptors have a nociceptive function, a range of chemical stimulants was applied to these receptors, including non-noxious stimuli such as ammonium …

The Efficacy Of Three Types Of Analgesic Drugs In Reducing Pain In The Rainbow Trout, Oncorhynchus Mykiss, Jessica J. Mettam, Lois J. Oulton, Catherine R. Mccrohan, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Recent research has shown the possibility of pain perception in fish; therefore, the use of analgesia or “painkillers” should be considered for invasive procedures. However, there is relatively little information on the effectiveness of analgesic drugs nor on the appropriate dose for fish. This study assessed the efficacy of three types of drug: an opioid, buprenorphine, a non-steroidal anti-inflammatory drug (NSAID), carprofen and a local anaesthetic, lidocaine. Each drug was tested at three doses on rainbow trout that were noxiously stimulated and the most effective dose was also given to fish experiencing no pain to investigate side-effects. Ventilation rate and …

Three Rs Approaches In The Production And Quality Control Of Fish Vaccines, Paul J. Midtlyng, Coenraad F.M. Hendriksen, Elisabeth Balks, Lukas Bruckner, Lawrence Elsken, Øystein Evensen, Kjetil Fyrand, Allison Guy, Marlies Halder, Penny Hawkins, Gunn Kisen, Anne Berit Romstad, Kira Salonius, Patrick Smith, Lynne U. Sneddon

Veterinary Science and Medicine Collection

The workshop on Three Rs Approaches in the Production and Quality Control of Fish Vaccines aimed a) to identify animal tests currently stipulated for the production and quality control of fish vaccines and to highlight animal welfare concerns associated with these tests; b) to identify viable options to replace, reduce, and refine animal use for fish vaccine testing; and c) to discuss the way forward and set out how the Three Rs may be implemented without jeopardizing the quality of the vaccines. The workshop participants -- experts from academia, regulatory authorities, a scientific animal welfare organization, and the fish vaccine …

Nociception In Fish: Stimulus–Response Properties Of Receptors On The Head Of Trout Oncorhynchus Mykiss, Paul J. Ashley, Lynne U. Sneddon, Catherine R. Mccrohan

Veterinary Science and Medicine Collection

This study examined stimulus–response properties of somatosensory receptors on the head of rainbow trout, Oncorhynchus mykiss, using extracellular recording from single cells in the trigeminal ganglion. Of 121 receptors recorded from 39 fish, 17 were polymodal nociceptors, 22 were mechanothermal nociceptors, 18 were mechanochemical receptors, 33 were fast adapting mechanical receptors and 31 were slowly adapting mechanical receptors. Mechanical thresholds were higher in polymodal nociceptors than in either slowly adapting or fast adapting mechanical receptors, whereas thermal thresholds of mechanothermal nociceptors were higher than those of polymodal nociceptors. Polymodal nociceptors and mechanochemical receptors gave similar responses to topical applications of …

The Evidence For Pain In Fish: The Use Of Morphine As An Analgesic, Lynne U. Sneddon

Veterinary Science and Medicine Collection

This paper discusses the evidence for pain perception in fish and presents new data on morphine analgesia in fish. Recent anatomical and electrophysiological studies have demonstrated that fish are capable of nociception, the simple detection of a noxious, potentially painful stimulus and the reflex response to this. To prove pain perception, it must be demonstrated that an animal’s behaviour is adversely affected by a potentially painful event and this must not be a reflex response. The present study examined the acute effects of administering a noxious chemical to the lips of rainbow trout (Oncorhynchus mykiss) to assess what changes occurred …

Do Fishes Have Nociceptors? Evidence For The Evolution Of A Vertebrate Sensory System, Lynne U. Sneddon, Victoria A. Braithwaite, Michael J. Gentle

Veterinary Science and Medicine Collection

Nociception is the detection of a noxious tissue-damaging stimulus and is sometimes accompanied by a reflex response such as withdrawal. Pain perception, as distinct from nociception, has been demonstrated in birds and mammals but has not been systematically studied in lower vertebrates. We assessed whether a fish possessed cutaneous nociceptors capable of detecting noxious stimuli and whether its behavior was sufficiently adversely affected by the administration of a noxious stimulus. Electrophysiological recordings from trigeminal nerves identified polymodal nociceptors on the head of the trout with physiological properties similar to those described in higher vertebrates. These receptors responded to mechanical pressure, …

Trigeminal Somatosensory Innervation Of The Head Of A Teleost Fish With Particular Reference To Nociception, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Trigeminal somatosensory receptors have not been characterised in teleost fish and studies in elasmobranchs have failed to identify nociceptors. The present study examined the trigeminal nerve of a teleost fish, the rainbow trout (Oncorhynchus mykiss) to determine what types of somatosensory receptors were present on the head of the trout specifically searching for nociceptors. Single unit recordings were made from receptive fields on the head of the fish innervated by the trigeminal nerve. Each receptive field was tested for sensitivity to mechanical, thermal and chemical stimulation. Five different receptor types were found: fast adapting receptors responding to mechanical stimulation; slowly …

Description Of A Poorly Differentiated Carcinoma Within The Brainstem Of A White Whale (Delphinapterus Leucas) From Magnetic Resonance Images And Histological Analysis, Sam H. Ridgway, Lori Marino, T. P. Lipscomb

Veterinary Science and Medicine Collection

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI.

Acceptance Of Simulated Oral Rabies Vaccine Baits By Urban Raccoons, John Hadidian, Suzanne R. Jenkins, David H. Johnston, Peter J. Savarie, Victor F. Nettles, David M. Manski, George M. Baer

Veterinary Science and Medicine Collection

In summer 1986, a study was conducted to evaluate raccoon (Procyon lotor) acceptance of oral baits that could be used for rabies vaccination, One thousand wax-coated sponge bait cubes were filled with 5 mg of a seromarker (iophenoxic acid), placed in polyethylene bags, and hand-distributed in an 80 ha area within an urban National Park in Washington, D.C. (USA), After 3 wk, target and nontarget animals were trapped and blood samples collected to evaluate bait uptake. Thirty-three of 52 (63%) raccoons had elevated blood iodine levels indicating they had eaten at least one bait, 13 (25%) were negative, and six …

Applications Of Laboratory Technology In The Evaluation Of The Risk Of Rabies Transmissions By Biting Dogs And Cats, Donald C. Blenden, Manuel J. Torres-Anjel, F. T. Satalowich

Veterinary Science and Medicine Collection

While rabies is not a common disease in domestic animal species of the United States, potential exposures to rabies in the form of bites are very common and increasing. A nationwide study conducted among general hospitals shows that 1 percent of emergency room visits are for animal bites, of which 80-90 percent are inflicted by the dog (Callaham 1980). This figure is conservative, as the study did not include pediatric hospitals, the bite of victims that progress only to a physician's office, or those that receive no medical care at all. In Missouri alone, this study would infer about 1500 …

T-61 Use In The Euthanasia Of Domestic Animals: A Survey, Andrew N. Rowan

Veterinary Science and Medicine Collection

A variety of techniques have been proposed and employed for the killing of domestic animals but relatively few have survived as suitable agents for euthanasia-namely, the induction of painless, suffering-free death. Some agents, such as strychnine, curariform agents, or potassium salts cause suffering while others have other disadvantages. 'lbday, dogs and cats are commonly euthanatized with sodium pentobarbital or with T-61 which is a mixture of a central nervous system narcotic, a paralytic agent, and a local anesthetic. The use of T-61 was first reported in the United States in 1963 (Quin 1963). The substance gradually became more popular because …

Review Of Literature On Use Of T-61 As An Euthanasic Agent, Laura Dalia Barocio

Veterinary Science and Medicine Collection

The tools of evaluating the degree of distress in animals being killed include electroencephalography (EEG), electrocardiography (ECG), and measurement of blood pressure and respiration. Sound clinical and behavioral observations should also not be abandoned in the evaIuation process.

There are many methods which may be employed to reach the same end results, but the ideal method should satisfy several criteria: 1. It should be painless; 2. It should cause unconsciousness instantaneously and death within minutes; 3. It should not cause undue anxiety, alarm, fear, panic, behavior, struggling, vocalization, muscle spasms or clinical signs of automatic activation (e.g., convulsions) before unconsciousness; …

Amputation Of Vibrissae In Show Dogs, Thomas E. Mcgill

Veterinary Science and Medicine Collection

Dogs of many different breeds competing in the show-ring are routinely subjected to amputation of the vibrissae, organs that are commonly and incorrectly called "whiskers." This procedure is thought to give the animal's head a cleaner look, which in turn supposedly increases its chances of winning. There are several tricks involved in "whisker trimming" since the animals can retract each vibrissae at least one-quarter inch. Furthermore, they often object strenuously to the operation.