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Physiological and Biochemical Responses in Tilapia (Oreochromis Mossambicus) Exposed to Cadmium and Chlorpyrifos

KrishiKosh

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Title Physiological and Biochemical Responses in Tilapia (Oreochromis Mossambicus) Exposed to Cadmium and Chlorpyrifos
 
Creator Padmanabha, A
 
Contributor Reddy, H.R.V
Sudhir Kumar Das
Prabhudeva, K.N
Gangadhar Gowda
Shrikrishna, Isloor
Sridhar, N.B.
 
Subject Cadmium, Chlorpyrifos, Combined toxicity, Physiological responses, Biochemical responses and Oreochromis mossambicus.
 
Description Ph.D. Thesis
Increasing input of environmental contaminants such as heavy metals and pesticides to aquatic ecosystems has generated the need to understand and evaluate the biological effects of xenobiotics on aquatic biota. The use of physiological and biochemical markers in fishes has been widely used for both marine environments and for continental waters. Prominent among these markers are physiologic variables; behaviour, oxygen consumption, food consumption, ammonia excretion, Oxygen:Nitrogen ratio, growth rate and biochemical variables; cholinesterase enzymes, antioxidant enzymes, non-enzymatic antioxidants and total protein levels are used as stress indicators. The toxicological assessment of water contamination through sublethal bioassays becomes relevant because they allow early detection of adverse effects on particular test organisms.
The present study aimed at detecting the variation of physiological and biochemical responses in Tilapia (Oreochromis mossambicus) caused by individual and combination of heavy metal, Cadmium and organophoshorous pesticide, Chlorpyrifos in response to short-term and long-term exposures to sublethal concentrations (1/5th and 1/10th of LC50 value) of test toxicants for 7, 14 and 21 days. Individual lethal toxicity of Cadmium (Cd) and Chlorpyrifos (CPF) indicated that the 96 h LC50 value for fish were found to be 169.80 ppm and 0.022 ppm respectively, combined lethal toxicity of varying Cadmium + constant Chlorpyrifos was 92.04 ppm and combination of varying Chlorpyrifos + constant Cadmium was 0.016 ppm. These results indicate that, Cadmium in combination with Chlorpyrifos becomes more toxic (synergistic) compared to its individual exposure. Similarly, Chlorpyrifos become more toxic (synergistic) to Tilapia fish fingerlings in the presence of Cadmium compared to its individual exposure.
The effects of test toxicants on the physiological and biochemical responses were remarkable. Oxygen consumption rate, food consumption rate, ammonia excretion rate, Oxygen:Nitrogen ratio and growth rate of the fishes was affected to sublethal concentrations of test toxicants. Variations in physiological responses are the consequence of impaired oxidative metabolism. Alteration in the antioxidant enzymes, glutathione system, non-enzymatic antioxidants and induction of lipid peroxidation reflects the oxidative stress of test toxicants in the experimental fish. The decreased activity of cholinesterase enzymes signifies the inability of the enzymes in countering the toxic effects of the Cadmium and Chlorpyrifos. Depletion in protein content in the gills, liver, kidney, brain and muscle indicate the utilization of large amounts of protein under a toxic stress. Hence, the present investigation recommends the utility of physiological and biochemical responses as diagnostic tools to assess toxic effects in fishes. All the results were statistically significant at P
 
Date 2016-06-25T11:30:55Z
2016-06-25T11:30:55Z
2015-08-10
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/68009
 
Language en
 
Format application/vnd.openxmlformats-officedocument.wordprocessingml.document
 
Publisher Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar