Use of pneumocystoplasty for overinflation of the swim bladder in a goldfish

Single and mixture toxicity of cadmium and copper to swim bladder in early life stages of Japanese medaka (Oryzias latipes)

Toxicity observed in aquatic ecosystems often cannot be explained by the action of a single pollutant. Likewise, evaluation standards formulated by a single effect cannot truly reflect the environmental quality requirements. The study of mixtures is needed to provide environmental relevance and knowledge of combined toxicity. In this study, the embryos of Japanese medaka (Oryzias latipes) were treated with individual and binary mixture of copper (Cu) and cadmium (Cd) until 12 days post-fertilization (dpf). Hatching, mortality, development, histology and gene expression were assessed. Our results showed that the highest concentration mixture of Cd (10 mg/L) and Cu (1 mg/L) affected survival, hatching time and hatching success. Occurrence of uninflated swim bladder was the highest (value) with exposure to 10 mg/L Cd. Swim bladder was commonly over-inflated in a mixture (0.1 mg/L Cd + 1.0 mg/L Cu) exposure. Individuals exposed to the mixture (0.1 Cd + 1.0 Cu mg/L) showed up to a 7.69% increase in swim bladder area compared to the control group. The mixtures containing 0.1 or 10 mg/L Cd, each with 1.0 mg/L Cu resulted in significantly increased of Pbx1b expression, higher than any Cd or Cu alone (p < 0.01). In the co-exposure group (0.1/10 Cd + 1.0 Cu mg/L), Pbx1b expression was found at 12 dpf but not 7 dpf in controls. Higher concentrations of Cd may progressively reduce Pbx1b expression, potentially explaining why 75% of individuals in the 10 mg/L Cd group failed to inflate their swim bladders. Additionally, the swim bladder proved to be a valuable bio-indicator for biological evaluation.

Buoyancy disorders in pet axolotls Ambystoma mexicanum: three cases

As far as we are aware, there are no previous reports on the pathologic conditions of buoyancy disorders in Ambystoma mexicanum. Herein, we describe various clinical test results, clinical outcomes, and the pathological findings of an experimental pneumonectomy procedure in 3 A. mexicanum exhibiting abnormal buoyancy. The 3 pet A. mexicanum were adults, and their respective ages and body weights were 1, 5, and 6 yr and 48, 55, and 56 g. Two of these cases were confirmed via radiographic examination to have free air within the body cavity, and all 3 cases were found via ultrasonography to have an acoustic shadow within the body cavity and were diagnosed with pneumocoelom. Lung perforations were detected macroscopically in 2 of the cases, and all 3 cases had fibrosis in the caudal ends of the lungs. Removal of the lung lesions eliminated the abnormal buoyancy in all 3 cases. We concluded that air had leaked into the body cavity from the lungs, and we propose that lung lesions are an important cause of buoyancy disorders in A. mexicanum.

A veterinary guide to the fish gastrointestinal tract

For veterinarians to better understand aquatic animal health, the most basic veterinary foundation begins with understanding piscine anatomy and physiology. General observations of fish behavior, anatomy, and food apprehension can provide more valuable diagnostic information than advanced laboratory testing alone. This article highlights anatomic differences of fish species occupying different environmental niches, using a case to show the use of modern veterinary diagnostics, and introduces additional topics in piscine gastroenterology related to toxins, nutrition, probiotics, and infectious diseases.

Diagnostic techniques and treatments for internal disorders of Koi (Cyprinus carpio)

The most common problems that occur in koi involve external pathogens and environmental conditions. Techniques for external fish examination and water quality analysis have been well described in the veterinary literature. However, there are also some internal disorders of koi, such as gas bladder abnormalities affecting the fish's buoyancy, neoplasia, egg binding (roe retention), and spinal disorders that can be diagnosed with common veterinary medical procedures. Diagnostic techniques along with available treatments for these disorders are presented in this article.

Neoplasia in fishes

Similar to higher vertebrates, neoplasia is not an uncommon disease in fishes, which are the largest group of vertebrates. However,neoplasia in fishes is generally a benign condition with relatively few exceptions of malignant disease. The objective of this discussion is to provide an overview of neoplasia and the various neoplastic disease conditions in fishes according to organ system,including the few neoplasms of species that are familiar to the aquatic animal or exotic animal practitioner. The discussion also considers the various nonneoplastic lesions in fishes that may be confused with neoplasms, and treatment of neoplastic disease in fishes that is generally restricted to surgical intervention.