Roy P. E. Yanong

Pharmacokinetic Studies of Florfenicol in Koi Carp and Threespot Gourami Trichogaster trichopterus after Oral and Intramuscular Treatment

Abstract The pharmacokinetics of florfenicol were studied in koi carp Cyprinus carpio (hereafter, koi) and threespot gourami Trichogaster trichopterus after oral (50 mg/kg) and intramuscular (25 mg/kg) administration of the drug in warm water conditions (24–25°C). The estimates of clearance, volume of distribution, and half-life were 0.05 L · h−1 · kg−1, 1.0 L/kg, and 16 h, respectively, in koi. In threespot gourami, the corresponding estimates were 0.32 L · h−1 · kg−1, 2.0 L/kg, and 4 h. In koi, minimal drug absorption was observed after bath treatment. Analysis of florfenicol leaching from fish feed indicated that about 50–80% of the coated drug is lost and is not available for therapeutic benefit for either species. The minimum inhibitory concentrations of florfenicol, determined for bacterial isolates from tropical fish, ranged from 0.5 to 2 μg/mL. For effective dosing regimens in koi and threespot gourami, the differences in pharmacokinetics should be considered in future studies.

Survey of Ovaprim Use as a Spawning Aid in Ornamental Fishes in the United States as Administered through the University of Florida Tropical Aquaculture Laboratory

Abstract Ovaprim is a commercial product used as a spawning aid in fishes and contains a salmon gonadotropin-releasing hormone analog and a dopamine antagonist. Since 2005, the use of Ovaprim in commercial ornamental fish production has been through enrollment with the University of Florida Tropical Aquaculture Laboratory in an Investigational New Animal Drug (INAD) study. A database is maintained to provide information to the U.S. Food and Drug Administration on product effectiveness and target animal safety. There were 25 fish species in 17 genera and 10 families in the INAD database. Ostariophysan fishes constituted 84% of the species and 99.9% of the individuals. The goldfish Carassius auratus was numerically the dominant species (80% of individuals). Nearly 40,000 fish in total were injected with Ovaprim; ovulation was induced in 92% of females and spermiation was induced in 96% of males, primarily reflecting extensive use in cyprinid fishes. Conversely, average success rates across all species were ...

Issues Regarding the Use of Sedatives in Fisheries and the Need for Immediate-Release Options

Abstract The lack of an immediate-release sedative (i.e., one for which no postsedation holding or withdrawal period is required) jeopardizes fish and fisheries research and poses considerable risk to those involved in aquatic resource management and the operation of public hatcheries and commercial fish farms. Carbon dioxide may be used as an immediate-release sedative, but it is slow-acting and difficult to apply uniformly and effectively. Tricaine methanesulfonate (MS-222) is easier to apply but requires a 21-d withdrawal period. The lack of an immediate-release sedative approved by the U.S. Food and Drug Administration (FDA) is a consequence of numerous factors, including the complexities of the approval process, the substantial human and monetary resources involved, and the specialized nature of the work. Efforts are currently underway to demonstrate the safety and effectiveness of benzocaine- and eugenol-based products as immediate-release sedatives. However, pursuing approvals within the current fr...

Occurrence of Piscirickettsiosis-Like Syndrome in Tilapia in the Continental United States

From 2001 to 2003, tilapia (Oreochromis sp.) farms in Florida, California, and South Carolina experienced epizootics of a systemic disease causing mortality. The fish exhibited lethargy, occasional exophthalmia, and skin petechia. The gills were often necrotic, with a patchy white and red appearance. Grossly, the spleen and kidneys were granular with whitish irregular nodules throughout. Granulomatous infiltrates were observed in kidney, spleen, testes, and ovary tissues, but not in the liver. The granulomas contained pleomorphic coccoid bacteria, measuring 0.57 ± 0.1 × 0.8 ± 0.2 μm, that were Giemsa-positive, acid-fast-negative, and Gram-negative. The bacteria had a double cell wall, variable electron-dense and -lucent areas, and were present in the cytoplasm and within phagolysosomes. The syndrome was associated with cold stress and poor water conditions. These findings are consistent with an infectious process caused by a Piscirickettsia-like bacterium described previously in tilapia in Taiwan and Hawaii. This report involves the first identified cases of a piscirickettsiosis-like syndrome affecting tilapia in the continental United States.

Nutrition of Ornamental Fish

Because thousands of species comprise the aquarium hobby, ornamental fish nutrition is an art and a science that must be approached systematically and holistically. Examinations of species-specific anatomy and natural history are useful starting points. Food fish research provides fundamental nutritional information, but food fish are not ideal models for all ornamentals. This article briefly addresses freshwater and marine fish issues, including considerations for pond fish and live foods.

Effects of Tricaine Methanesulfonate, Hypno, Metomidate, Quinaldine, and Salt on Plasma Cortisol Levels following Acute Stress in Threespot Gourami Trichogaster trichopterus

Abstract Blood plasma cortisol concentration is an indicator of stress in fish, and anesthetics may serve to ameliorate stress and reduce the cortisol response. Previous studies have concentrated on cold- and warmwater species; little information exists for tropical fishes. Mortalities are increased after handling stress of threespot gourami Trichogaster trichopterus (Osphronemidae), a commonly cultured tropical ornamental fish. Plasma cortisol levels were evaluated in threespot gourami after a handling stressor and treatment with one of four anesthetics—tricaine methanesulfonate (TMS; 60 mg/L), metomidate (0.8 mg/L), quinaldine (5 mg/L), and Hypno (0.14 mg/L)—or salt (NaCl; 3 g/L). Fish in all anesthetic treatments had significantly lower cortisol levels than either salt-treated fish or the untreated controls. Therefore, the use of such anesthetics should be beneficial in reducing handling stress. Based on our data, further studies refining the use of anesthetics, particularly metomidate and quinaldine, ...

Preliminary Investigations of Hydrogen Peroxide Treatment of Selected Ornamental Fishes and Efficacy against External Bacteria and Parasites in Green Swordtails

The objectives of these preliminary studies were to evaluate the use of hydrogen peroxide (H2O2) for the treatment of selected species of ornamental fishes and its efficacy in treating external bacteria and parasites. In the first part of the study, fish of five species (serpae tetra Hyphessobrycon eques (also known as Serpa tetra H. serpae), tiger barb Puntius tetrazona, blue gourami Trichogaster trichopterus, suckermouth catfish Hypostomus plecostomus, and green swordtail Xiphophorus hellerii) were exposed to H2O2 for 1 h at concentrations between 6 and 34 mg/L or for 24 h at concentrations between 1 and 6 mg/L. The results were species specific: green swordtails tolerated all of the treatments, serpae tetras and tiger barbs were sensitive only to the highest concentration, and mortalities of suckermouth catfish and blue gourami were recorded in every treatment. In the second part of the study, clinically healthy green swordtails and fish infested with external motile rod-shaped bacteria (i.e., Ichthyobodo spp., Trichodina spp., and Gyrodactylus spp.) were treated with several concentrations of H2O2. A single H2O2 treatment of 3.1 mg/L or more for 1 h effectively eliminated external bacteria, concentrations of 6.5 mg/L or more appeared to effectively kill Ichthyobodo spp., and none of the treatments tested was effective against Trichodina spp. or Gyrodactylus spp. These preliminary findings suggest that H2O2 is effective for treating certain external bacterial infections and flagellate infestations in some species of ornamental fish at the dosages tested. Other treatment regimens may need to be tested for effectiveness against Trichodina spp. and Dactylogyrus spp.

Molecular and immunohistochemical diagnosis of Francisella noatunensis subsp. orientalis from formalin-fixed, paraffin-embedded tissues

Members of the genus Francisella (viz., F. noatunensis subsp. orientalis [Fno] and F. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. In the present study, 68 archived formalin-fixed, paraffin-embedded (FFPE) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detection of the Fno intracellular growth loci C (iglC) gene and by immunohistochemistry for the demonstration of Fno antigens. The results revealed a high correlation between these 2 diagnostic techniques validating their use for the diagnosis of Fno infection in archived FFPE tissues and confirming the presence of Fno in fish species from the Cari y years of the present century.

Association of Mycobacteria in Recirculating Aquaculture Systems and Mycobacterial Disease in Fish

Mycobacterium marinum isolates cultivated from tissue containing granulomatous lesions in Florida pompano Trachinotus carolinus and from biofilm samples collected from their tank and water recirculating system had identical (L1 of 11 bands) repetitive-sequence-based polymerase chain reaction (rep-PCR) DNA fingerprints. A second M. marinum clone sharing 4 of 11 rep-PCR bands with the first clone was isolated from some fish tissues but not from system samples. Water samples yielded low numbers of colonies of mycobacteria (0.08-1.3/mL), but high numbers were recovered from biofilms (260-12,000/swab) and filters (63-21,000/ filter). Mycobacterium hemophilum, M. chelonae, M. trivale, M. gastri, and M. gordonae were isolated from system samples alone.

Atypical presentation of mycobacteriosis in a collection of frogfish (Antennarius striatus).

Abstract Severe systemic mycobacteriosis without typical granuloma formation was diagnosed in a group of six mature, captive, striated frogfish Antennarius striatus approximately 5 mo after fish originating from Brazil were purchased by Mote Marine Laboratory Aquarium. Beginning 1 mo after spawning, over a period of 9 mo, individuals began to show a variety of signs including egg retention, ocular opacity, poor buoyancy control, ascites with coelomic distension, skin lesions, and anorexia. Two fish died, and four were euthanatized. At necropsy, raised pigmented skin nodules; pale pink gills; and pale yellow or tan, fatty livers were noted. A systemic fungal infection was diagnosed histopathologically in one female, and the remaining fish had severe, systemic, histiocytic inflammation and necrosis. Although large numbers of acid-fast bacterial rods were identified in each fish, no bacteria were cultured aerobically from skin, kidney, spleen, liver, or brain. Mycobacterium marinum was cultured from the liver of the last fish that was euthanatized after it became moribund and failed to respond to symptomatic treatment.