ZINC AND CALCIUM SUPPLEMENTATION TO COMBAT CADMIUM INDUCED BIOACCUMULATION IN FRESH WATER TELEOST OREOCHROMIS MOSSAMBICUS (TILAPIA)

摘要

Objective: The present work was carried out to know the therapeutic role of zinc (Zn) and calcium (Ca) supplementation to combat cadmium (Cd) induced toxicity in selected tissues of freshwater teleost, Oreochromis mossambicus (Tilapia) exposed to Cd. Methods: The freshwater fish, Oreochromis mossambicus ( Tilapia ) was brought from the local ponds and were allowed for acclimatization to the laboratory conditions. After acclimatization, fishes were exposed to 1/10 th of LC 50/ 48 hr of Cd i.e.5 ppm for 7, 15 and 30days (d) long sojourn. After 15d Cd exposure, fish were divided into three groups. The 1 st group was supplemented with Zn at a dose of 1 ppm; Group–II was supplemented with Ca at the dose of 1 ppm and Group–III received a combination of both Zn and Ca at the above said doses for 7, 15 and 30d. After specific time intervals, fish were sacrificed and liver, kidney, brain, gill and muscle tissues were isolated in ice cold conditions. Then the tissues were used for bioaccumulation studies. Results: A significant (P<0.05) elevation was observed in bioaccumulation levels during Cd exposure. The high amount of Cd accumulation was found in 30d Cd-exposed kidney (22.353±0.410 μg/g) followed by other tissues. After supplementation with Zn and Ca, Cd accumulation was progressively decreased in all the test tissues. The maximum percentage of Cd depletion was found in 30d Ca-supplemented muscle tissue. Conclusion: Our findings clearly envisage that the Zn and/or Ca supplementation is very effective in reducing the Cd toxicity in the teleostean fish, Oreochromis mossambicus.