Journal of Environmental Biology

Sub-lethal impact of carbaryl on food utilization in the freshwater

prawn Macrobrachium malcolmsonii

Author Details

P. Saravana Bhavan

(Corresponding author)

Department of Zoology, Bharathiar University, Coimbatore - 641 046, India

e-mail: bhavanps1967@yahoo.in, bhavan@buc.edu.in

P. Geraldine

Department of Animal Science, Bharathidasan University, Tiruchirappalli - 620 024, India

R. Sowdeswari

Department of Zoology, Bharathiar University, Coimbatore - 641 046, India

Publication Data

Paper received:

19 February 2010

Revised received:

30 July 2010

Re-revised received:

17 August 2010

Paper accepted:

24 September 2010

Abstract

This study determines the toxic effect of carbaryl (Sevin^? 50% W.P) on the food utilization parameters in intermoult juveniles of the prawn, Macrobrachium malcolmsonii. The prawns (4.5-5.0 cm in length and 1.0-1.25 g wet wt.) were exposed to three sub-lethal concentrations of carbaryl (5.15, 7.73 and 15.47 mg l^-1) for duration of 40 days. The toxic medium was renewed daily. The prawns were fed ad libitum with known energy quantity of boiled goat liver on daily basis. The overall wet weight gain was calculated. The energy lost through unconsumed food (15-60%), faeces (15-109%), ammonia excretion (9-27%) and moults (13-26%) of the prawns were calculated. The feeding rate, the rate and efficiency of absorption, the metabolic and food conversion rates and the gross and net food conversions efficiencies were found to be significantly declined (p<0.05) in test prawns when compared to that of the control. The energy lost through faeces, ammonia excretion and exuvia was found to be significantly elevated (p<0.05) in test prawns than that of the control.? The effect of carbaryl on the bioenergetics parameters was severe in the highest sub-lethal concentration, less in the intermediate concentration and least in the lowest sub-lethal concentration. The results indicated that decrease in feeding, absorption, metabolism and food conversion are interdependent and toxicity of carbaryl diverting energy from production to maintenance pathways, which ultimately resulting in declined growth of M. malcolmsonii.

Key words

Bioenergetics, Prawn, Macrobrachium malcolmsonii, Carbaryl

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