Effects of Arsenic (III) and Chromium (VI) Toxicity on Digestive Enzymes’ Activities of Anabas testudineus (Bloch)

Effects of two different concentrations of arsenic (8.88 mg/l and 17.76 mg/l i.e., 25 and 50% of LC 50 value) respectively and chromium (15.45 mg/l and 30.90 mg/l i.e., 25 and 50% of LC 50 value respectively) were evaluated on digestive enzymes of Anabas testudineus for a period of 30 days under laboratory condition. Here As1 and As2, and Cr1 and Cr2 were referred to indicate the 25 and 50% of LC 50 value of arsenic and chromium respectively. The result of different enzymes in different tissues was as follows: amylase and lipase activities showed highest in stomach, i.e., 466.81 and 283.33% respectively at 50% concentration of chromium; but moderate (272.78% at 25% of Cr and 264.65% at 50% of As) followed by lowest 219.07% at 25% As concentration. Protease activity at different concentrations of metals was in the order of As2 > As1 > Cr2 > Cr1. Protease activity showed highest in As2 or 50% concentration of As (397.92%) and lowest in 25% of Cr (316.39%). Lipase activity showed highest increment in intestine under As2 (409.23%) and lowest activity in Cr1 (137.84%). In intestine, the protease activity increased at As1 (288.99%) and the highest at As2 i.e., 367.39% compared to other concentrations. The significant changes ( p > 0.05) in the enzyme activities in the different tissues like stomach and intestine in regard to different doses were investigated along with regression lines. So, it can be inferred that digestive enzyme activities of A. testudineus may be considered as the potential biomarkers for arsenic and chromium contamination in aquatic systems.