Implications of comparative ventral body wall histology on selection of abdominal surgical approach and closure in 12 species of fish.

A ventral midline surgical approach for fish celiotomy is commonly performed in veterinary clinical medicine and research, although the relevant ventral body wall anatomy of many fish species is not well documented. Histological evaluation of tissue samples from the ventral body wall of 12 fish species was performed to provide a reference for surgical approach and closure decisions. The width between muscle bundles running parallel to the long axis and total thickness of tissue layers varied among species. An appreciable space between longitudinal muscles of the ventral body wall and a lack of muscle, vessels and nerves on midline in all species examined supports recommendations of ventral midline incisions to spare important structures. Dense connective tissue consistent with an aponeurosis between musculature along the ventral body wall was not observed in any species evaluated. Connective tissue was concentrated within the dermis of all species evaluated, with an additional layer of collagen along the coelomic membrane in Russian sturgeon Acipenser gueldenstaedtii, koi Cyprinus carpio, goldfish Carassius auratus, black drum Pogonias cromis, black seabass Centropristis striata, tomtate Haemulon aurolineatum and scup Stenotomus caprinus. A sufficiently wide space on ventral midline for practical targeting during the surgical approach is present in A. gueldenstaedtii, C. carpio, striped bass Morone saxatilis, H. aurolineatum, P. cromis, rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta. Sand perch Diplectrum formosum, C. auratus, S. caprinus, grey triggerfish Balistes capriscus and black sea bass Centropristis striata have a negligible space between longitudinal muscles on midline. The variation in ventral body wall structure observed in this study helps inform surgical decision making for celiotomy incision and closure in these species.

Predicting the factors influencing the inter- and intraspecific survival rates of riverine fishes implanted with acoustic transmitters.

Biotelemetry is a central tool for fisheries management, with the implantation of transmitters into animals requiring refined surgical techniques that maximize retention rates and fish welfare. Even following successful surgery, long-term post-release survival rates can vary considerably, although knowledge is limited for many species. The aim here was to investigate the post-tagging survival rates in the wild of two lowland river fish species, common bream Abramis brama and northern pike Esox lucius, following their intra-peritoneal double-tagging with acoustic transmitters and passive integrated transponder (PIT) tags. Survival over a 2-year period was assessed using acoustic transmitter data in Cox proportional hazards models. Post-tagging survival rates were lowest in the reproductive periods of both species, but in bream, fish tagged just prior to spawning actually had the highest subsequent survival rates. Pike survival was influenced by sex, with males generally surviving longer than females. PIT tag detections at fixed stations identified bream that remained active, despite loss of an acoustic transmitter signal. In these instances, loss of the acoustic signal occurred up to 215 days post-tagging and only during late spring or summer, indicating a role of elevated temperature, while PIT detections occurred between 18 and 359 days after the final acoustic detections. Biotelemetry studies must thus always consider the date of tagging as a fundamental component of study designs to avoid tagged fish having premature end points within telemetry studies.

A Description of a Noninvasive Surgical Training Pathway Using Translational Tools to Teach Intracoelomic Implantation of Acoustic Transmitters in Fish.

Researchers engaged in surgical implantation of acoustic transmitters into fish must receive adequate and appropriate training to ensure the welfare of their subjects and the quality of the data collected. Increasingly, researchers are being encouraged to partner with veterinarians to improve training and to consider the principles of animal welfare in training. Here, we describe a five-stage training pathway, including implementation of new training tools (the Translational Training Tools and field certification), that was developed collaboratively by researchers and veterinarians and addresses the "three Rs" of animal welfare in the context of surgical training. The three Rs include animal replacement, reduction of the number of animals used, and refinement of techniques to decrease or eliminate pain or distress. The Translational Training Tools, described in the context of the training pathway, use tools as replacement models during training to reduce the number of animals used and allow for refinement of surgical skills prior to working on live animals. The purpose of this paper is to document the Translational Training Tools and the training pathway, which will be useful in developing de novo protocols for review by Institutional Animal Care and Use Committees and similar bodies.

Fish Surgery: Presurgical Preparation and Common Surgical Procedures.

Fish surgical procedures are commonplace in aquaria, zoos, laboratory facilities, and pet clinical practice. To incorporate fish surgery into a clinical setting, an understanding of anatomic differences between mammals and fish, bath anesthetics, and recirculating anesthesia techniques must be developed; a system or different size systems to accommodate anesthesia and surgery of particular species of concern at an institution or practice constructed; and familiar mammalian surgical principles applied with some adaptations. Common surgical procedures in fish include coeliotomy for intracoelomic mass removal, reproductive procedures, gastrointestinal foreign body removal, radiotransmitter placement, and integumentary mass excision.

Eye Removal Surgeries in Exotic Pets.

This article covers considerations and techniques of eye removal surgeries in exotic pets. After issues including surgical indications, anesthesia, patient preparation, and instrumentation are explored, surgical techniques are described. Enucleation/exenteration and modified evisceration are discussed, with species-specific nuances of small mammals, birds, reptiles, snakes, amphibians, and fish highlighted.

[Effects of transmitter's surgical implantation on fish: research progress].

Surgical implantation is generally accepted as the preferred attachment method for longterm fish telemetry study, but the negative effects of this surgical implantation on fish should not be ignored. The key for the successful fish telemetry study is that the existence and attachment of the transmitters in the experimental fish would not have negative effects on the normal fish physiology or behavior. Therefore, it is necessary to assess the potential negative effects of surgical implantation of transmitter on experimental fish prior to telemetry monitoring. This paper reviewed the overseas research progress in the effects of surgical implantation of transmitter on fish, and discussed the possible negative effects and affecting degrees of transmitters, surgical procedure, environmental factors, ad anthropogenic factors in the process of transmitter' s surgical implantation in fish. Some suggestions were put forward to reduce the potential negative effects, and the research directions of surgically implanted transmitters in fish in China were prospected.

Nonlethal acquisition of large liver samples from free-ranging river sturgeon (Scaphirhynchus) using single-entry endoscopic biopsy forceps.

Harvesting of liver samples for toxicologic and other laboratory analyses is frequently undertaken in free-ranging fish to evaluate accumulations of various pollutants and chemicals. However, commonly used, lethal techniques for collecting liver tissues are unacceptable when dealing with protected species. We report the use of a nonlethal, single-entry, endoscopic technique using saline infusion to examine and collect large liver samples using optical biopsy forceps from 16 free-ranging sturgeon (Scaphirhynchus spp.) during 25 and 27 January 2010. Under tricaine methanesulfonate anesthesia and following the introduction of the optical biopsy forceps (with a 5-mm telescope) through a 1-2-cm ventral midline skin incision, liver examination and collection of biopsies averaging 0.9 g, ranging up to 1.4 g, and representing up to 12% of total liver tissue were successful. All fish made uneventful recoveries and necropsy examinations the following day failed to indicate any significant hemorrhage or iatrogenic trauma. We recommend the use of large optical biopsy forceps as a practical, nonlethal alternative for collection of large liver biopsies from sturgeon and other fish.

Neotropical Ichthyology

Constituir-se em um fórum internacional de divulgação e discussão de pesquisas originais sobre diversidade de peixes marinhos, estuarinos e de água doce Neotropicais.

Stress and its relation to endocrine function in captive female Siberian sturgeon (Acipenser baeri).

Stress responses to numerous environmental conditions have been studied in a wide range of fish species. Defining the relationship between stress and endocrine function is particularly critical to long-lived species such as sturgeons, whose economic viability relies heavily on proper endocrine function for the production of caviar. In this study, we examined the induced stress response, defined by plasma cortisol and glucose concentrations, and its relationship to plasma 17beta-estradiol, testosterone and 11-ketotestosterone concentrations in cultured female Siberian sturgeon (Acipenser baeri). Fish were acutely stressed using capture and confinement for a period of 4 h, and blood samples were drawn according to four treatment regimens: treatment 1, fish were bled at 0 h; treatment 2, fish were serially bled at 0 h, 1 h and 4 h; treatment 3, fish were bled at 1 h and 4 h; treatment 4, fish were bled at 4 h only. Fish were surgically sexed immediately after drawing blood at 0 h. After 1 h of acute stress, fish demonstrated a marked increase in plasma cortisol concentration, which remained elevated throughout the 4-h sampling period. The plasma concentration of sex steroids did not exhibit an inverse relationship with plasma cortisol concentration. Plasma testosterone concentration was significantly elevated during the periods of greatest stress. Plasma estradiol and 11-ketotestosterone (11-KT) concentrations were not affected by the acute stressors in this experiment. Serial bleedings, however, affected the associated stress response, which is an important consideration for future studies with this species. This is the first study to define the relationship between stress and possible changes in sex steroid concentration in this threatened and commercially important species.

Surgery in fish research: common procedures and postoperative care.

As the use of fish models in biomedical research increases, so too does the need for individuals working in laboratory animal science to be familiar with surgical procedures in these animals. The author presents a primer on fish surgery with an emphasis on research applications.

Surgical implantation of transmitters into fish.

Although the Animal Welfare Act does not cover poikilotherms, individual institutions and policies and legal requirements other than the Animal Welfare Act (e.g., the US Public Health Service and the Interagency Research Animal Committee's Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training) require the review of projects involving fish by institutional animal care and use committees (IACUCs). IACUCs may, however, lack the knowledge and experience to evaluate fish projects judiciously, especially when the projects are in field settings. Surgeries involving implantation of transmitters and other instruments into the coelom, which now comprise a very common research tool in the study of free-ranging fishes, are examples of surgeries that use a broad spectrum of surgical and anesthetic techniques, some of which would not be considered acceptable for similar work on mammals. IACUCs should apply the standards they would expect to be used for surgeries on homeotherms to surgeries on fish. Surgeons should be carefully trained and experienced. Surgical instruments and transmitters should be sterile. Regulations and laws on the use of drugs in animals should be followed, particularly those concerned with anesthetics and antibiotics used on free-ranging fish. Exceptions to surgical procedures should be made only when circumstances are extreme enough to warrant the use of less than optimal procedures.

[Fresh water fish farming--fishing ponds and "cesarean section"]. / Süsswasserfischproduktion--Angelteiche und "Kaiserschnitt".

Present knowledge on the capability of fish to feel pain and of suffering is presented. According to these data it has to be supposed, that fish are able to feel fish. Suffering and damage can be proven by biochemistry and morphology. Under these aspects, angling ponds and cesarean section in sturgeon have to be regarded as a violation of the German animal welfare act.

Cardiovascular actions of lungfish bradykinin in the unanaesthetised African lungfish, Protopterus annectens.

Bradykinin (BK) isolated from plasma of the African lungfish, Protopterus annectens, contains four amino acid substitutions compared with BK from mammals (Arg(1)-->Tyr, Pro(2)-->Gly, Pro(7)-->Ala, Phe(8)-->Pro). Bolus intra-arterial injections of synthetic lungfish BK (1-1000 pmol/kg body wt.) into unanaesthetised, juvenile lungfish (n=5) produced a dose-dependent increase in arterial blood pressure and pulse pressure. The maximum pressor response occurred 2-3 min after injection and persisted for up to 15 min. The threshold dose producing a significant (P<0.01) rise in pressure was 50 pmol/kg and the maximum increase, following injection of 300 pmol/kg, was 9.3 +/- 2.3 mmHg. Injection of the higher doses of lungfish BK produced a significant (P<0.05) increase in heart rate (2.8 +/- 0.8 beats/min at 100 pmol/kg). In contrast, bolus intra-arterial injections of mammalian BK, in doses up to 1000 pmol/kg, produced no significant cardiovascular effects in the lungfish. The data support the existence of a functioning kallikrein-kinin system in the lungfish and demonstrate that the ligand-binding properties of the receptor(s) mediating the cardiovascular actions of lungfish BK are appreciably different from mammalian B1 and B2 receptors.

Methods of positioning fish for surgery or other procedures out of water.

Several methods are available for positioning fish and other aquatic species during surgery or other experimental procedures out of water. This paper reviews current methods in the light of criteria for humane handling, and suggests the implementation of a novel method, currently used for positioning mammals during surgery, that gives optimal support and a minimum of damage.

Surgery in fish.

Surgery in fish is feasible and practical for clinical and research applications. Certain adjustments in standard surgical procedures are necessary to accommodate piscine tissue handling, skin sensitivity, aqueous respiration, anatomic variations, and patient size. General considerations for fish surgery, including anesthesia, presurgical evaluation, equipment, suture selection, and surgical site preparation, have been presented here. Procedures described include celiotomy, enucleation, pseudobranchectomy, swim bladder surgery, gonadectomy, liver and kidney biopsy techniques, telemetry device implantation, and vascular catheterization.

Effects of salinity, hypophysectomy, and prolactin on whole-animal transepithelial potential in the tilapia Oreochromis mossambicus.

We have examined whether two recently isolated forms of tilapia (Oreochromis mossambicus) prolactin exert similar effects on osmoregulatory physiology. The effects of salinity, hypophysectomy, and replacement therapy with tilapia prolactins on whole-animal transepithelial potential (TEP), gill Na+, K+-ATPase activity, and plasma ions were determined. When intact fish adapted to 25% seawater (SW) were transferred to different salinities, TEP reached a steady state after 10 hr; TEP increased with increasing salinity from fresh water (FW) to 75% SW but was stable from 75 to 125% SW. Plasma osmolality, [Na+], and [Cl-] of these fish 24 hr after salinity change showed that fish in 100 and 125% SW had greater osmotic perturbation than those transferred to lower salinities. Following a 5-day recovery period in 25% SW, hypophysectomized fish transferred to FW for 10 hr had significantly lower TEP and plasma ion levels than either sham-operated fish or intact fish under the same conditions. Injection of hypophysectomized fish with "small" prolactin (tPRL177), "large" prolactin (tPRL188), or a combination of both (0.5 micrograms/g body weight) 22 hr and again 20 min prior to transfer from 25% SW to FW, restored TEP and plasma ion levels to those of sham-operated fish. Neither prolactin affected the TEP or plasma ions of sham-operated (intact) fish. Hypophysectomized fish had lower gill Na+,K+-ATPase activity than sham-operated fish in FW, but prolactin injections as described above did not affect gill Na+,K+-ATPase activity in either hypophysectomized or sham-operated fish. Our results indicate that the two forms of prolactin are indistinguishable with regard to several aspects of tilapia osmoregulation.