Four-Eyed Fish (A. anableps) Fingerlings Demonstrated Multiple Birth Defects Suggestive of Nutritional Deficiencies

Abstract

In a colony of four-eyed fishes (A. anableps) some females produced offspring demonstrating birth-defects. At external inspection, the ventral midline was open over variable lengths. In some cases, it was combined with lordosis, kyphosis, or scoliosis. Affected specimens also suffered from cataracts. Histopathology revealed widely scattered degeneration of myofibers. Sheath cells of the notochord had proliferated, resulting in asymmetric shape distortion of vertebrae and indentations in the spinal cord. The spinal cord revealed an extensive axonal degeneration. The liver appeared mottled due to focal fat infiltration. Cataracts of ocular lenses appeared as vacuolization of lens fibers. The multiple pathologies noted may have been due to nutritional imbalances because the colony received a carnivore-based diet. Feeding ecology of Anableps is one of omnivory with a predominance of herbivory. This may have resulted in lesions comparable to deficiencies in Vitamin E, Vitamin C, and Selenium.