Asian Journal of Fisheries and Aquatic Research

This study investigated the effects of aluminium on the blood characteristics of fingerling Clarias albopunctatus, for which information is limited. A total of two hundred and fifty (250) fingerlings of Clarias albopunctatus were exposed to aluminium ions at concentrations of 0.01 mg/l, 0.02 mg/l, 0.03 mg/l, 0.04 mg/l, 0.05 mg/l and 0.06 mg/l, with a control experiment (0.00), for a period of 96 hours in a static bioassay. The 96-hour LC₅₀ of aluminium ions for Clarias albopunctatus was 0.05 mg/l, and the Maximum Admissible Toxicant Concentration (MATC) ranged between 0.005 mg/l and 0.0005 mg/l. The haematological parameters examined after 21 days were red blood cell count, white blood cell count, packed cell volume, haematocrit and haemoglobin. The white blood cell count increased rapidly with increasing concentrations of aluminium ions. Differential cell counts showed a marked increase in lymphocytes and eosinophils, with decreases in neutrophils, monocytes and basophils. The increases in lymphocytes, eosinophils and total leucocytes indicated infections that developed after exposure to aluminium ions. Sub-acute exposure to aluminium ions altered the normal functioning of the haematopoietic system in African catfish, leading to changes in red and white blood cell profiles. This study on Clarias albopunctatus indicated that aluminium toxicity induced hypochromic macrocytic anaemia, with reductions in red blood cell (RBC) counts, haemoglobin (Hb) content and packed cell volume (PCV), as well as changes in immune cells.