Skeletal and swim bladder deformities in rohu, Labeo rohita (Hamilton, 1822) from grow-out pond, Tamil Nadu, India
P Kathirkaman, A Gopalakrishnan, S Muhilvannan, V Singaravel, T Gunasekaran
The present study was conducted to investigate the skeletal deformities and swim bladder malformations in rohu (Labeo rohita). The fish were collected in the newly constructed cultured pond, Bhuvanagiri, Tamilnadu, India. Various patterns of skeletal deformities were observed in 13 of 497 sampled specimens (2.6 %). Deformities were diagnosed using a variety of clinical, radiographic and histopathological techniques. Witnessed deformities included kyphosis and lordosis. The swim bladder was deformed, with no connection between the two major chambers and with absence of pneumatic ducts. Histopathological investigations of ventral musculature tissue samples revealed the congestion of blood capillaries, dermal edema, inflammatory cells, as well as excess of melanophores and muscular edema. Observed deformities were confirmed using radiographic and histopathological techniques. The explanation of the witnessed deformities could not be safely determined, but possible attributions of causes are discussed.