A study on carbohydrate moieties of gills and air-breathing organs of the walking catfish Clarias batrachus (Linn.) following exposure to arsenic

Abstract

The chronic sublethal (1 ppm) effects of an arsenic (As) salt, disodium arsenate heptahydrate (DSA) was examined on the carbohydrate moieties of the gills and air-breathing organs (ABO) of the walking catfish Clarias batrachus Linn. The glycogen content increased quantitatively in the gills during initial stages followed by a decrease after 7 days and throughout treatment. The fall was significant after 30–45 days exposure. This was also accompanied by an increase followed by a decrease in mucogenic activity of the gills. Glycoproteins (GPs) along with the mucous cells stained strongly for carboxylic groups and O-sulfated esters. Unlike the gills, the air-breathing organs showed an increase in glycogen content that surpassed the level of untreated control fish after prolonged exposure. The data indicate that As disturbed aerial respiration after chronic exposure. Mucogenic activity in the air-breathing organs fell markedly and always remained below the level of untreated control fish. Similar to the gills, the air-breathing organs also showed a strong affinity for GPs containing carboxylic groups and O-sulfated esters.

Keywords:

• ABO
• Clarias batrachus L.
• arsenic
• gill
• glycogen
• glycoproteins
• histochemistry

Acknowledgement

Financial support to Ajai Kumar Singh from the Council of Scientific and Industrial Research, Govt. of India, New Delhi, India, is gratefully acknowledged.