Temperature induces lead toxicity in Pangasius hypophthalmus: an acute test, antioxidative status and cellular metabolic stress

Climate change and pollution are the most vulnerable stressors that are anticipated increasingly to affect all living organisms including fishes. The aquatic ecosystems are the most affected ecosystem due to contamination and global increasing temperature. In view of the above, the present study delineates 96-h median lethal concentration of heavy metal, lead alone and in combination with high temperature (34 A degrees C) by conducting static non-renewable acute toxicity bioassay in Pangasius hypophthalmus (average weight 3.65 +/- 0.75 g). Further, the effect of different definitive doses (80, 82, 84, 86, 88 and 90 mg/L) of lead alone and high temperature on cellular metabolic response was probed. The LC50 of lead was found to be 84.93 mg/L, whereas in combination with high temperature it was 83.10 mg/L in P. hypophthalmus. Catalase, superoxide dismutase and glutathione-S-transferase were noticeably higher (p < 0.01) in liver, gill and brain during lead exposure alone and in combination with high temperature. The activities of aspartate aminotransferase and alanine aminotransferase were significantly enhanced (p < 0.01) in muscle, liver and gill in dose- and time-dependent manners in lead-alone-exposed and in combination with high-temperature groups. The brain and liver acetylcholine esterase activities showed noticeable (p < 0.01) inhibition from 80 to 90 mg/L exposure of lead alone and with concurrent exposure to temperature than the control group. Overall results clearly indicate that acute exposure of lead and high temperature led to pronounced deleterious alterations on cellular and metabolic activities of P. hypophthalmus.