Histological and computed tomographic evaluation of a parasitic conjoined twin in hybrid catfish (Ictalurus punctatus [Rafinesque] X Ictalurus furcatus [Lesueur])

Abstract

There is growing use of hybrid catfish (Ictalurus punctatus ♀ X Ictalurus furcatus ♂) in commercial aquaculture to utilize hybrid vigour to improve production A conjoined twin specimen found during the course of production studies by the United States Department of Agriculture Catfish Genetic Research Unit (USDA-CGRU) was submitted to the Aquatic Research and Diagnostic Laboratory (ARDL). After preliminary inspection, it was transported to Mississippi State University, College of Veterinary Medicine for further evaluation. The specimen was examined using both computed radiography and computed tomography antemortem. Following humane euthanasia, the specimen was examined both grossly and histologically. Tissues from both fish were also submitted for genetic analysis to determine whether twins were derived from the same egg. This report records the presentation and examination of a pair of conjoined hybrid catfish (I. punctatus X Ictalurus furcatus).

Salmonid fish: model organisms to study cardiovascular morphogenesis in conjoined twins?

“…However, there are reports on conjoined fish twins that reach adulthood; a 1.7 kg wild caught rainbow trout ( Oncorhynchus mykiss ) [ 3 ], a 3.5 kg farmed Atlantic salmon ( Salmo salar ) [ 4 ], a 30.5 cm long farmed hybrid catfish ( Ictalurus punct - atus ♀ x Ictalurus furcatus ♂) [ 5 ], a 1.9 cm long Endlers guppy ( Poecilia wingei ) [ 6 ], all with a parasitic twin grown into the body wall. In the hybrid catfish [ 5 ], the parasitic twin was mostly vestigial, consisting of partial elements of the musculoskeletal, gastrointestinal and central nervous systems, while the normal twin appeared to be viable and showed no signs of pathology based on histology, gross examination, and radiology. Although such parasitic fish twins most probably must depend on nutrients and oxygen supplied by their normal sibling, the cardiovascular system of conjoined fish twins has never been studied in detail.…”