A report on freshwater tailless flea, Simocephalus vetulus from Haridwar, located in foothills of Shivalik Himalaya in Uttarakhand, India

The Cladocerans, commonly known as “Water fleas” form a primitive freshwater group of micro crustacean zooplankton of the freshwater ecosystem. They play an important role in the aquatic food chain and also contribute significantly to zooplankton dynamics and secondary productivity in freshwater ecosystems. The animals used in the present study were identified as Simocephalus vetulus with the help of identification keys described by various authors in the previous studies from other parts of India. In the present study, the occurrence of “freshwater tailless flea”, S. vetulus (Crustacea- cladocera) is reported for the first time from freshwater bodies in Haridwar, located in foothills of Shivalik Himalayan region in Uttarakhand. The presence of S. vetulus “tailless water flea” will be helpful as a lab model for the health status of aquatic bodies as well as environmental monitoring

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

MORPHOLOGICAL AND HISTOCHEMICAL CHARACTERIZATION OF HAEMOCYTES OF FRESH WATER PRAWN, Macrobrachium dayanum (CRUSTACEA-DECAPODA)

Haematological profile of the M. dayanum will be helpful in monitoring the health status of this prawn species which is a potential animal for fresh water aquaculture as well as a good model for monitoring the pollution level of the fresh water ecosystems. The haemocytes of the freshwater prawn, Macrobrachium dayanum were classified into seven types based on morphology and behaviour like formation of pseudopodia, encapsulation of foreign particles clumping etc., under phase contrast microscope and their reactions with different stains. The seven types of haemocytes included prohaemocytes, plasmatocytes, spindle cells, granular haemocytes, spherule cells, adipohaemocytes and the cystocytes. The structural details and their significance in haemocyte classification along with probable functions like transport of food, phagocytosis and encapsulation of foreign particles, defense against various infections, hardening of exoskeleton, prevention of blood loss by promoting immediate clotting, confinement of invasive organism and detoxification, of different haemocyte types have been discussed

STUDIES ON THE STRUCTURE OF HEART OF TWO FRESHWATER PRAWNS UNDER LIGHT MICROSCOPE

Heart of fresh water prawns, Macrobrachium lamarrei (H. Milne Edwards) and Macrobrachium dayanum (Handerson) are situated in cephalothoracic cavity above the hepatopancreas and gonads. Triangular hearts are perforated by five pairs of ostia in both the species. Each ostium is situated in depression with guard-cell like valves. Histologically there are two layers, outer epicardium or adventitia, and inner myocardium or muscularis separated with each other by thin basal lamina. Musular strands divide the lumen of heart into three chambers, two small lateral and one large median. Anteriorly five arteries and posteriorly two arteries emerge from heart. The heart of M. dayanum is slightly bigger in size than M. lamarrei. Functional aspects of different components of heart have also been discussed

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