Studies on the toxic effects of some heavy metals on enzymological parameters in Indian major carps
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Date
2013
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Publisher
CCSHAU
Abstract
An accelerated release of heavy metals into the aquatic environment poses serious water
pollution problems because of their toxicity, persistence and bio-accumulation in food chains. The
present investigation was therefore aimed at studying the effect of heavy metals Cd and Zn alone and in
combination on behavior, growth parameter, blood serum enzymes, ions and heavy metal residues in
Indian major carps i.e., Catla catla, Labeo rohita, and Cirrhinus mrigala.
In Indian major carps, growth performance in terms of live weight gain, growth percent gain
in body weight, specific growth rate, decreased maximally in all the fish species viz. C. catla, L.
rohita, and C. mrigala. exposed to Cd+Zn treatment. While a significant (P<0.05) increase in FCR
values was observed in all the heavy metal treated fishes. Maximum increase in alkaline phosphatase
and maximum decreases in enzymes (cholinesterase, lipase and lactate dehydrogenase) were in fish’s
C. catla, L. rohita, and C. mrigala in the treatments of Cd+Zn. Same in case of combination of two
heavy metals, Cd+Zn at 0.06ppm induced maximum reduction in metal ions (Sodium, Calcium and
Chloride) and maximum increase in potassium ion contents in blood serum of fish C. mrigala, followed
by L. rohita and least reduction was in the fish C. catla. Maximum increased in heavy metals contents
in blood serum was in fish C. catla than in L. rohita and C. mrigala.
The effects of Cd metal alone and in combination with Zn were further more distinct for
digestive enzyme alterations. Activity of all the digestive enzymes was reduced in all the heavy metal
treatments. Protease and amylase enzyme activity reduced maximum reduced in C. mrigala and
amylase enzyme activity reduced minimum decreases in C. catla. Thus, Cd alone and in combination
with Zn proved most toxic in all the fish species inducing alterations in behaviour, external body
symptoms, growth performance, and body composition with reference to body digestive enzymes.
The order of reduction of enzymes, metals ions and heavy metals content due to different
treatments was Zn >Cd >Cd+Zn and species-wise reduction was in order of C. catla > L. rohita.> C.
mrigala.
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Keywords
Enzymes, Biological phenomena, Toxicity, Irrigation, Biological development, Inorganic acid salts, Concentrates, Environment, Water, Proteins