Alternative injection route to medicate fish.

Posted on by TheFishVet - Richmond's School of Fish

Often there is a need to regularly inject fish with medication as a course of treatment. This can be antibiotics and anti-inflammatories to treat bacterial infections or post-operation. For those who prefer that their fish do not become “pin cushions”, read this article below.

Abstract
March 1, 2005, Vol. 226, No. 5, Pages 784-788
doi: 10.2460/javma.2005.226.784

Evaluation of a method of intracoelomic catheterization in koi

Gregory A. Lewbart, MS, VMD, DACZM Deborah A. Butkus, BS Mark G. Papich, DVM, MS, DACVCP Angela K. Coleman, BS Dr. Howard N. Krum, MS, VMD Dr. Edward J. Noga, MS, DVM
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606. (Lewbart, Butkus, Coleman, Krum, Noga); Departments of Molecular and Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606. (Papich); Present address is Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1 Canada. (Coleman); Present address is the Georgia Aquarium, 2451 Cumberland Pkwy, Atlanta, GA 30339. (Krum)

Objective—To develop an easy and safe method for catheterization and determine the pharmacokinetics of a single dose of enrofloxacin after intracoelomic administration in koi.

Design—Prospective study.

Animals—20 healthy koi.

Procedure—6 koi were anesthetized with tricaine methanesulfonate, and a 23-gauge, three-fourths-inch butterfly catheter was inserted into the coelomic cavity and secured. Catheters were flushed daily for 6 days with 0.4 mL of sterile saline (0.9% NaCl) solution containing heparin (100 units of heparin in 250 mL of saline solution) without removing koi from the aquarium. At the end of the sixth day (144 hours), each of the 6 catheterized koi and 6 uncatheterized (control) koi was anesthetized individually. Enrofloxacin (10 mg/kg [4.5 mg/lb]) was administered to catheterized koi via the injection port and to control koi via a 23-gauge needle in the same site as the catheter placement. A pharmacokinetics study was performed on multiple plasma samples to validate the efficiency of the catheter. Reliability of the catheterization method was determined in 8 koi.

Results—All 6 catheters remained patent and effective for the 6 days prior to the start of the pharmacokinetics study. Results for the 2 routes of administration were comparable, and all koi survived the study without any detectable clinical problems.

Conclusions and Clinical Relevance—An intracoelomic catheter was effective and safe when maintained in koi for at least 6 days. This would be highly beneficial for veterinarians, clients, and fish, especially when intracoelomic administration of a drug would require daily or more frequent dosing. (J Am Vet Med Assoc 2005;226: 784–788)

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How to combat nitrite toxicity?

Posted on by TheFishVet - Richmond's School of Fish

I’ve used a combination of salt (NaCl), vitamin C and large partial water changes to combat the effects to nitrite poisoning. This new study suggests that using in-feed salt will prevent deleterious effects of nitrite. Useful to know when setting up new aquaria!

Another treatment option would be to add methylene blue to the water to prevent methaemoglobinaemia. More about how to interpret the nitrite test results and how to manage the situation is available by downloading some free pages taken from “Fish Vetting Essentials” – FVetEssn_Nitrite

Remember, to avoid “new tank syndrome”, make sure you establish aquaria by slowly increasing the biomass, avoid excessive feeding and most importantly, perform regular water quality testing.

Aquaculture International: Journal of the European Aquaculture Society
  Volume 20, Number 1 (February 2012)
     Susceptibility of Nile tilapia (Oreochromis niloticus) fed with dietary sodium chloride to nitrite toxicity
   Authors: Thomas Welker 1, Chhorn Lim 2, Mediha Yildirim-Aksoy 2, Phillip Klesius 2
   Author Affiliations:
 1: Agricultural Research Service, United States Department of Agriculture, Hagerman Fish Culture Station, 3059F National Fish Hatchery Road, Hagerman, ID, USA
 2: Aquatic Animal Health Research Unit, Agricultural Research Service, United States Department of Agriculture, 990 Wire Road, Auburn, AL 36832, USA
   Source: Aquaculture International: Journal of the European Aquaculture Society, Volume 20, Number 1 (February 2012)
   Page Numbers: 159 – 176
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   Abstract:
Abstract

Juvenile Nile tilapia (Oreochromis niloticus) were fed with diets supplemented with 0 or 6% NaCl for 10 weeks. Tilapia were exposed to approximately 21 mg/l nitrite-N after 5 and 10 weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were sampled before (baseline, pre-exposure) and after 24 h nitrite exposure to determine the effects of dietary NaCl on mortality, hematology (hematocrit, hemoglobin, and methemoglobin), and plasma electrolyte dynamics (nitrite, chloride, sodium, and potassium). After 10 weeks of feeding, tilapia were also challenged with Streptococcus iniae to determine the effect of sodium chloride on immunity. Tilapia fed with the NaCl-supplemented diet had significantly higher weight gain compared with the control group, which was associated with a significant increase in feed intake in the NaCl group. Mortality from nitrite exposure was lower in tilapia fed with the NaCl-supplemented diet compared with the control group at 5 and 10 weeks, but the differences were not significant. However, dietary NaCl supplementation caused a significant decrease in plasma nitrite levels after nitrite exposure. The dietary reduction in nitrite may be related to the increase in plasma chloride in the 6% NaCl-supplemented fish. A direct link between the effects of dietary NaCl supplementation on methemoglobin (MetHb) could not be established. Tilapia in this study were subjected to acute nitrite toxicity. Dietary sodium chloride may be more effective in protecting against nitrite toxicity at lower levels of nitrite, but the conditions at which it proves to be effective may be limited and requires further investigation. Feeding NaCl to tilapia did not affect susceptibility to S. iniae or immune function, but nitrite exposure cause a stress-related reduction in non-specific immune function. This is the first study to examine the effects of dietary salt on nitrite toxicity in tilapia.
   Citation: Thomas Welker, Chhorn Lim, Mediha Yildirim-Aksoy, Phillip Klesius . Susceptibility of Nile tilapia (Oreochromis niloticus) fed with dietary sodium chloride to nitrite toxicity. Aquaculture International: Journal of the European Aquaculture Society, Volume 20, Number 1 (February 2012), pp. 159-176, <http://ejournals.ebsco.com/direct.asp?ArticleID=49D283EE52CDA7E5886B&gt;
   URL: http://ejournals.ebsco.com/direct.asp?ArticleID=49D283EE52CDA7E5886B

Blood test for a snail!!

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A lot of information has been gained from the relatively recent abalone viral ganglioneuritis outbreak. You’ve heard of blood tests for humans, for your dogs and cats, but have you thought about doing the same for a snail?

The most recent study on the effects of the viral disease on abalone shows that their white blood cell count decreases.

Australian Veterinary Journal
Volume 90, Number 2 (January 2012)
Full text available Leucopenia associated with abalone viral ganglioneuritis
Authors: C Hooper 1, R Slocombe 2, R Day 3, S Crawford 4
Author Affiliations:
1: Gribbles Veterinary Pathology, 1868 Dandenong Rd, Clayton, VIC 3168 and Zoology Department, University of Melbourne, Parkville, VIC 3052, Australia; celia.hooper@gribbles.com.au
2: Faculty of Veterinary Science, University of Melbourne, Parkville, VIC, Australia. Zoology Department, The University of Melbourne, Parkville VIC, Australia.
3: Department of Zoology, University of Melbourne, Parkville, VIC, Australia.
4: School of Botany, University of Melbourne, Parkville, VIC, Australia.
Source: Australian Veterinary Journal, Volume 90, Number 2 (January 2012)
Page Numbers: 24 – 28
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Abstract: Objective To compare microscopic lesion severity with circulating total haemocyte counts (THC) in abalone affected by abalone viral ganglioneuritis (AVG).
Citation: C Hooper, R Slocombe, R Day, S Crawford . Leucopenia associated with abalone viral ganglioneuritis. Australian Veterinary Journal, Volume 90, Number 2 (January 2012), pp. 24-28,
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=44FD81EC9FE9D7C72982

WAVMA is an affiliate member of…

Posted on by TheFishVet - Richmond's School of Fish

World Small Animal Veterinary Association (WSAVA).

Read about the history of WAVMA (World Aquatic Veterinary Medical Association) – http://www.wsava.org/WAVMA.htm

How do fish move? Swim bladder function.

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BUOYANCY, LOCOMOTION, AND MOVEMENT IN FISHES
next term | Swimbladder Function and Buoyancy Control in previous termFishesnext term

B. Pelster

University of Innsbruck, Innsbruck, Austria

Available online 5 August 2011.

Abstract

Many previous termfishnext term use a gas-filled swimbladder as a buoyancy organ. The swimbladder originates as an unpaired dorsal outgrowth of the posterior foregut, the pharynx. While in physostomous previous termfishnext term the embryonic connection to the pharynx persists, in physoclistous previous termfishnext term it is lost during early development. In most previous termfishnext term larvae, initial inflation of the swimbladder is achieved by gulping air shortly after hatching, but some species have been reported to inflate the swimbladder without surfacing. Failure to inflate the swimbladder reduces viability. Hydrostatic pressure increases with increasing water depth. Accordingly, the volume of the flexible-walled swimbladder is reduced during descent and increases during ascent. In order to keep the swimbladder volume and thus the buoyancy status constant, previous termfishnext term must secrete gas into the swimbladder during descent and gas must be resorbed from the swimbladder during ascent. Gas secretion into the swimbladder requires the activity of gas gland cells, which acidify the blood and thus induce a decrease in its gas-carrying capacity. As a consequence, gas partial pressures in the blood increase, providing a pressure head for the diffusive transport of gas from the blood into the swimbladder. In a second step, the initial increase in gas partial pressure in the blood is multiplied by back-diffusion and countercurrent concentration of gas molecules in a countercurrent system, the rete mirabile. Thus, very high gas partial pressures can be achieved in swimbladder blood vessels, high enough to explain the presence of gas-filled swimbladders at a water depth of several thousand meters.

Keywords: Bohr effect; CO2 partial pressure; Countercurrent system; Gas gland; Gas partial pressure; Gas solubility; Glycolysis; Inert gas; Oxygen partial pressure; Pentose phosphate shunt; Physoclist previous termfish; Physostome previous termfish; Resorbing section; Rete mirabile; Root effect; Secretory section; Single concentrating effect

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http://www.sciencedirect.com/science/article/pii/B9780123745538001052

Don’t eat spoiled fish.

Posted on by TheFishVet - Richmond's School of Fish
Histamine fishnext term poisoning revisited

Leigh Lehanea, Corresponding Author Contact Information, E-mail The Corresponding Author, June Olleyb

a National Office of Animal and Plant Health, Agriculture, Fisheries and Forestry – Australia, GPO Box 858, Canberra, ACT 2601, Australia
b School of Agricultural Science, University of Tasmania, GPO Box 252–54, Hobart, Tasmania 7001, Australia

Received 29 February 2000; revised 11 March 2000; Accepted 16 March 2000. Available online 25 May 2000.

Abstract

Histamine (or scombroid) previous termfishnext term poisoning (HFP) is reviewed in a risk-assessment framework in an attempt to arrive at an informed characterisation of risk. Histamine is the main toxin involved in HFP, but the disease is not uncomplicated histamine poisoning. Although it is generally associated with high levels of histamine (≥50 mg/100 g) in bacterially contaminated previous termfishnext term of particular species, the pathogenesis of HFP has not been clearly elucidated. Various hypotheses have been put forward to explain why histamine consumed in spoiled previous termfishnext term is more toxic than pure histamine taken orally, but none has proved totally satisfactory. Urocanic acid, like histamine, an imidazolecompound derived from histidine in spoiling previous termfishnext term, may be the “missing factor” in HFP. cis-Urocanic acid has recently been recognised as a mast cell degranulator, and endogenous histamine from mast cell degranulation may augment the exogenous histamine consumed in spoiled previous termfishnext term. HFP is a mild disease, but is important in relation to food safety and international trade. Consumers are becoming more demanding, and litigation following food poisoning incidents is becoming more common. Producers, distributors and restaurants are increasingly held liable for the quality of the products they handle and sell. Many countries have set guidelines for maximum permitted levels of histamine in previous termfishnext term. However, histamine concentrations within a spoiled previous termfishnext term are extremely variable, as is the threshold toxic dose. Until the identity, levels and potency of possible potentiators and/or mast-cell-degranulating factors are elucidated, it is difficult to establish regulatory limits for histamine in foods on the basis of potential health hazard. Histidine decarboxylating bacteria produce histamine from free histidine in spoiling previous termfishnext term. Although some are present in the normal microbial flora of live previous termfishnext term, most seem to be derived from post-catching contamination on board fishing vessels, at the processing plant or in the distribution system, or in restaurants or homes. The key to keeping bacterial numbers and histamine levels low is the rapid cooling of previous termfishnext term after catching and the maintenance of adequate refrigeration during handling and storage. Despite the huge expansion in trade in recent years, great progress has been made in ensuring the quality and safety of previous termfishnext termproducts. This is largely the result of the introduction of international standards of food hygiene and the application of risk analysis and hazard analysis and critical control point (HACCP) principles.

AIR-BREATHING FISHES!

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AIR-BREATHING FISHESnext term |
The Biology, Diversity, and Natural History of Air-Breathing previous termFishesnext term: An Introduction

J.B. Graham

University of California at San Diego, La Jolla, CA, USA

Available online 5 August 2011.

Abstract

The broad phyletic distribution of air breathing among bony previous termfishesnext term, the diversity of this group’s aerial-respiratory specializations, and the diverse ways that bimodal breathing has permeated the natural history of many species provide an important comparative perspective on the evolution and biological significance of this adaptation. The long-term view of previous termfishnext term air breathing emphasizes its importance in the evolutionary transition to vertebrate terrestriality; a key role in this process was played by the previous termfishesnext term which were the first air-breathing vertebrates. On the other hand, air breathing in most extant previous termfishesnext term has not led to terrestriality. Rather, auxiliary air breathing, which has evolved independently in many groups, enables a species to remain in or to exploit an aquatic habitat from which it would otherwise be excluded.

Keywords: Air-breathing previous termfishesnext term; Amphibious air breathers; Aquatic air breathers; Bimodal breathing; Facultative air breathers; Hypoxia adaptation; Obligatory air breathers; Terrestrial adaptation

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Air-breathing organ (ABO) A structure or body surface of a previous termfishnext term having the specialized structural capacity for aerial gas exchange; utilized by air-breathing previous termfishesnext term to supplement the normal respiratory mode which is aquatic respiration using gills.
Amphibious air breathing The mode of air breathing when a previous termfishnext term is out of water.
Aquatic surface respiration (ASR) A hypoxia-driven behavior in which a previous termfishnext term surfaces and places its the mouth as close to the water surface as possible in order to ventilate the gills with the upper few millimeters of water that remains well oxygenated because of atmospheric diffusion.
Autapomorphy A specialization unique to one group and thus not useful for establishing relationships.
Bimodal respiration The capacity to exchange respiratory gases in both air and water and to do so either simultaneously or sequentially.
Continuous air breathing The frequent and regular occurrence of air gulping, even when aquatic oxygen levels are sufficient to sustain aquatic respiration. This behavior often indicates the use of ABO gas for functions other than respiration such as buoyancy.
Facultative air breathing Emergency aquatic air breathing initiated in response to a diminished capacity for aquatic respiration usually associated with aquatic hypoxia or some other stress factor.
Hypoxia-inducible factor (HIF-1α) Integrated hypoxia response that activates genes whose protein products either increase O2 transfer (i.e., erythropoiesis, Hb affinity increases, angiogenesis, etc.) or upregulate metabolic adaptation by regulating anaerobiosis and O2 consumption rate. HIF-1α induction is an ancient adaptation that first appeared in eukaryotic cells and thus long preceded the origin of metazoans.
Lung The principal aerial respiratory organ of all vertebrates and some primitive air-breathing previous termfishesnext term. An outpocketing along the vertebrate digestive tube having a vascular epitheilial surface that functions for aerial gas exchange through its connection to the body surface by a duct through which air can be inhaled and exhaled.
Obligatory air breathing A high degree of physiological dependence on air breathing for the maintenance of basal oxidative processes or to prevent suffocation. This is usually associated with a reduction in gill surface area that occurs with progressive specialization for air breathing.
Physoclistous gas bladder A gas-filled structure within the body of the previous termfishnext term that has lost its connection to the body surface and thus cannot function for gas exchange but retains functions for buoyancy and either or both sound production and sound reception.
Physostomous gas bladder A gas-filled structure within the body of a previous termfishnext term that is connected to the body surface by the pneumatic duct that allowing inflation or deflation. In different previous termfishesnext term, functions of this organ may include aerial respiration as well as buoyancy and both sound reception and production.
Placoderm Armored Paleozoic previous termfish that were the first vertebrates to have jaws.
Plesimorphy A primitive trait.
Pneumatic duct Tube linking the pharynx to either the lung or physostomous gas bladder which functions for the passage of air for either air breathing, volume control, or both.
Synapomorphy A specialized trait shared by two or more groups, which implies that an ancestral group also possessed this trait.
Tetrapodomorpha The group of vertebrates consisting of the tetrapods (four-limbed vertebrates) and their closest sarcopterygian (lobefin previous termfish) relatives which invaded the land during the Devonian period.

How do bacteria kill fish?

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Pathogenesis of gram-negative bacterial infections in warmwater fishnext term

Ronald L. Thune1, 2, 3, Lisa A. Stanley1, 2, 3, Richard K. Cooper1, 2, 3

a Department of Veterinary Science, Louisiana State University Agricultural Center USA
b Department of Veterinary Microbiology and Parasitology, Louisiana State University USA
c School of Veterinary Medicine, Louisiana State University Baton Rouge, Louisiana 70803, USA

Available online 22 September 2003.

Abstract

Knowledge concerning the pathogenesis of many bacterial diseases in previous termfishnext term is limited, especially in those diseases that occur in warmwater species. This limited knowledge base is due to the relative recent emergence of warmwater previous termfishnext term culture as a major industry in many parts of the world, and to the previous economic insignificance of warmwater aquaculture and the bacterial pathogens affecting warmwater species. This article is an overview of the important gram-negative pathogens of warmwater previous termfishnext term, including members of the genera Aeromonas, Edwardsiella, Pasteurella, Pseudomonas, and Vibrio. The current knowledge of the pathogenesis of these organisms is emphasized, including: the source of the pathogen, its preferred site and method for attaching to and penetrating the host, its adaptations for surviving the host immune system, and its strategies for obtaining nutrients required for proliferation and growth. Although information for many of these pathogens is limited, the intent of this article is to provide a baseline for the development of future research projects. Increases in worldwide aquaculture production will result in a demand for knowledge about the pathogenesis of bacterial pathogens in warmwater previous termfishnext term, because of its importance in making health management decisions, in deciding on treatment regimens, and in the development of vaccines.

Keywords: Virulence; Pathogenesis; Bacteria; Gram-negative; previous termFishnext term

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What do fish hear?

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HEARING AND LATERAL LINE | Psychoacoustics: What Fishnext term Hear

R.R. Fay

Loyola University Chicago, Chicago, IL, USA

Available online 5 August 2011.

Abstract

The ears of all previous termfishesnext term function like accelerometers and respond to acoustic particle motion. Some species, in addition, have sensitivity to sound pressure via an otophysic connection between the ears and a bubble of gas in the body. All previous termfishesnext term can hear within a frequency range extending from below 50 Hz to as high as 5000 Hz for some species. Most species have a best sensitivity in the range from 100 to about 1000 Hz. All previous termfishesnext term can discriminate between different frequencies with moderate accuracy, and sound detection in all previous termfishesnext term is subject to masking, or interference by external noise.

Keywords: Auditory scene analysis; previous termFishnext term audiograms; previous termFishnext term hearing; Frequency discrimination; Frequency range of hearing; Hearing sensitivity; Masking; Otolith organ; Saccule; Soundscape; Swimbladder; Utricle

Audiogram A graphical representation of sound detection thresholds at the range of frequencies that are audible.
Auditory scene analysis A perceptual capacity shared by all vertebrates, including previous termfishes, to segregate and respond independently to the individual sound sources that may be active simultaneously (e.g., the instruments of an orchestra).
Masking The reduction in audibility for one sound (termed ‘signal’) caused by the simultaneous presence of another sound (termed ‘noise’). Masking causes the threshold for the signal to be higher (less detectable) than it normally would without the masking noise.
Otophysic connection An anatomical linkage between a gas bubble (e.g., the swimbladder) and the inner ear that brings the motions of the gas bubble, caused by sound pressure, directly to the ears.
Psychophysics A technology of experimental psychology designed to allow the investigation of the relationships between the physical nature of a stimulus (e.g., sound) and the sensations and perceptions caused by the stimulus.
Soundscape The sum of all the sounds characteristic of an environment.
Weberian ossicles A series of bones that is specially adapted as an otophysic connection between the swimbladder and the inner ear in a group of previous termfishes known as Otophysi.