Copper sulphate induced changes in scaphognathite oscillations and oxygen consumption of fresh water prawn, Macrobrachium lamarrei (Crustacea- Decapoda)

Fresh water prawns, Macrobrachium lamarrei were subjected to acute concentration, 0.304 mg/l (96h LC50) of Copper sulphate to evaluate its effects on scaphognathite oscillations and oxygen consumption rate. Scaphognathite oscillations showed initial increase after 24h, thereafter significantly (t = 9.24; P<0.001) decreased up to 72h and finally tend to increase after 96h but remained below the controls where as oxygen consumption showed continuous decreasing trend through out the experiment up to 96h (t = 16.53; P<0.001) than control ones. Possible interaction of copper in relation to respiration of these economically important crustaceans has been discussed

Histopathological alterations in gills of freshwater prawn, Macrobrachium dayanum (Crustacea - Decapoda) after acute and sub-acute exposure of lead nitrate

Lead is a nonessential “grey listed” heavy metal, used in fuels, ceramics, paints and glass wares in industries and vehicles. After taking entry in aquatic ecosystem it becomes toxic and cause serious problem to plants and animals. Haematological, neurological, nephrological and histopathological effects of lead are well known. Fresh water prawn, Macrobrachium dayanum, a potential animal for freshwater aquaculture, subjected to acute and sub-acute concentration of lead nitrate (116.46 mg/l; 96h LC50 and 29.12 mg/l; 25% of 96h LC50) showed severe histopathological alterations in gills after 24, 48, 72 and 96h and 10, 20 and 30 day exposure. Chief alterations during acute exposure were thickening of gill plates, reduction in inter lameller spaces, cuticular irruption, inflammation and necrosis where as clumping of gill plates, hyperplasia, hypertrophied haemocytes with nuclear pycnosis and leakage of haemocytes in inter-lameller spaces as well as deposition of broken tissue debris near gill base were observed during sub-acute exposure. The severity of histopathological alterations was found duration dependant. Present study reveals that histological bio- markers provides complete information regarding heavy metal toxicity particularly lead to these economically important fresh water prawns, which can themselves serve as bio-indicator of worsening status of surface aquatic bodies.&nbsp

EFFECT OF LEAD NITRATE ON HAEMOCYTE MORPHOLOGY OF FRESHWATER PRAWN, Macrobrachium dayanum (CRUSTACEA-DECAPODA)

Lead (Pb), a non-essential “Grey listed” heavy metal is a serious threat to aquatic flora and fauna. The haematological, nephrological, histopathological and neurological effects of lead are well known in vertebrates. Present study aims to investigate effect of lead on morphology of haemocytes, a important component of immune system of freshwater prawn, Macrobrachium dayanum. Prawns, collected at “Gulala-Ghat” from river Gomti, Lucknow, subjected to acute and sub-acute concentrations of lead nitrate (116.46 mg/l, 96h LC50; 29.12 mg/l, 25% of 96h LC50) showed morphological changes in haemocytes after 24, 48, 72 and 96h in acute exposure and after 10, 20 and 30 days in sub-acute exposure. The chief morphological changes like surface blebbing, vacuolization, cytoplasmic darkening, fragmentation of nuclear material, cone formation, nuclear pycnosis and breaking of plasma membrane were noticed after acute exposure (116.46 mg/litre). Black granular depositions, nuclear pycnosis and fragmentation of nuclear material; pseudopodial projections, blackening of the plasma membrane, achromatia were observed after sub-acute exposure (29.12 mg/litre). These changes were pronounced in prohaemocytes, granulocytes, plasmatocytes and spindle cells. The severity of morphological changes was dose- and duration-dependent. The present study found a positive correlation between heavy metal lead exposure and morphological changes in haemocyte morphology leading to severe immune dysfunction in freshwater prawn M. dayanum. This parameter can be used as bio-marker in health monitoring of prawns as well as environmental monitoring without sacrificing the animal. &nbsp