Polydora infestation on Crassoslrea madrasensis : a study on the infestation rate and eradication methods

Polydora ciliata a common polychaete worm, which bores and resides within the oyster shells, was found in the oyster populations of this estuary. The percentage infestation in the oysters occurring in the natural bed and in different age classes of farmed oysters was studied. Infestation was low in the natural bed than in the farmed oysters. About 80% of small oysters (<6 month) were uninfested in the natural bed while in the farmed oysters of the same age group, only 44% were uninfested. The severity of infestation was observed to increase with age in the natural bed as well as in farmed oysters. Experiments were conducted to eradicate these worms by dip treatments in formalin, chlorine and freshwater. Formalin treatments in three different doses, 1000,500 and 250ppm for 30 minutes, I hand 2 h respectively were capable of removing 79.6%, 69.1% and 69.6% worms from oysters with minimum mortality (6.6,1.6 and 0% mortality) to test oysters. Eradication treatment using chlorine at doses 1000, 700 and 500 ppm for 3,5 and 6 h were successful in eliminating 78.3%, 65.1 % and 57.7% worms from shells with test oyster mortality of 15%, 11.6% and 3.3%. Freshwater treatment for 3,6, 9 and 12h and aerial exposure after brushing the oysters with formalin were not effective in eradicating the mudworm

Efficiency of letrozole loaded PLGA nanoparticles on sex reversal of Poecilia reticulata (Peters, 1859)

Males of Poecilia reticulata showed extreme diversity in color, particularly of their fins, while the females lack the bright colors and are largely whitish. Such extreme variability of color and finnage lead to demand of males in the markets. The aim of present work was to develop a new Letrozole (LTZ)-loaded PLGA nanoparticles for effective delivery of the masculinization drug, letrozole, as an alternative to commercially available masculinization agents. The LTZ-loaded PLGA NPs were prepared by solvent displacement technique. The particle size of LTZ-loaded PLGA NPs was analyzed using LICOMP particle size analyzer and was found to be in the range of 72 nm to 520 nm with average size of 221.5±63.3 nm. Zeta potential was estimated to be about 21.35 mV with loading efficiency of 43.63±4.63 %. In the present study, a series of experiments were carried out to induce masculinization using LTZ-loaded PLGA nanoparticles during the sex differentiation period. Guppy (P. reticulate) fry were treated with LTZ-loaded PLGA nanoparticles at dosages 5, 25, 50 and 100 ppm/kg diet for 10, 15 and 30 days. The gonopodium index and GSI showed increasing order in male and female respectively with dose of LTZ-loaded nanoparticles. The results indicated an increase in the proportion of males with dosage and duration of treatment. This has been done for the first time using nanotechnology efficiently which has shown an increase in the male population of Poecilia reticulata with lesser dose of nano-encapsulated Letrozole (LTZ)-loaded PLGA nanoparticles drug as compared with naked control Letrozole (LTZ) drug delivery

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Not AvailablePolydora ciliata a common polychaete worm, which bores and resides within the oyster shells, was found in the oyster populations of this estuary. The percentage infestation in the oysters occurring in the natural bed and in different age classes of farmed oysters was studied. Infestation was low in the natural bed than in the farmed oysters. About 80% of small oysters (<6 month) were uninfested in the natural bed while in the farmed oysters of the same age group, only 44% were uninfested. The severity of infestation was observed to increase with age in the natural bed as well as in farmed oysters. Experiments were conducted to eradicate these worms by dip treatments in formalin, chlorine and freshwater. Formalin treatments in three different doses, 1000,500 and 250ppm for 30 minutes, I hand 2 h respectively were capable of removing 79.6%, 69.1% and 69.6% worms from oysters with minimum mortality (6.6,1.6 and 0% mortality) to test oysters. Eradication treatment using chlorine at doses 1000, 700 and 500 ppm for 3,5 and 6 h were successful in eliminating 78.3%, 65.1 % and 57.7% worms from shells with test oyster mortality of 15%, 11.6% and 3.3%. Freshwater treatment for 3,6, 9 and 12h and aerial exposure after brushing the oysters with formalin were not effective in eradicating the mudworm.Not Availabl

High prevalence of Aeromonas and Pseudomonas infections among cage cultured Pangas catfish from the reservoirs of Maharashtra, India

Cage farming of Pangas catfish (Pangasionodon hypophthalmus) in small reservoirs is primarily profitable. Still, sustainability in terms of disease and environmental impact issues remains unsolved. In the present study, Pangas catfish from selected farms were screened for bacteria and parasites from 2017-18. In the present study, several Gram-negative bacterial species, including Edwardsiella tarda, Aeromonas hydrophila, A. veronii, Pseudomonas putida, Enterobacter cloacae, and Plesiomonas shigelloides, were isolated. A high prevalence of Aeromonas and Pseudomonas infections was noticed in cage farms. The most prevalent isolate was A. veronii (9 isolates), followed by P. aeruginosa and P. putida, revealing the presence of biotic stress. Furthermore, potential human pathogenic bacteria, particularly Klebsiella pneumoniae, P. aeruginosa, Acinetobacter baumannii, Citrobacter freundii, and Morganella morganii, were isolated. Histopathological analysis of the vital organs concluded the extent of damage caused due to the biotic stress in the cage culture system. The antibiotic sensitivity test implied resistance of bacteria for Sulphamethoxazole and Tetracycline. Some of them were resistant to multiple drugs, the risk for public health. Water temperature, dissolved oxygen, pH, Aeromonas, Pseudomonas, and Plesiomonas were identified by principal component analysis as significant abiotic and biotic stress factors. This information helps design predictive disease models

Growth and survival of pearlspot, Etroplus suratensis (Bloch, 1790) fry using practical diets incorporated with different levels of mosquito fern

The present study was carried out to evaluate the growth and survival of pearlspot, Etroplus suratensis (Bloch, 1790) fry using practical diets incorporated with different levels of mosquito fern, for 60 days. The fry with average length and weight of 25±0.1 mm and 0.54±0.03 g, respectively were reared at stocking density 15 fry/100 L in brackishwater. Four iso-nitrogenous (30% crude protein) and iso-calorific diets were formulated with incorporation of 0, 10, 20 and 30% powdered fermented azolla. Fry were fed at the rate of 7-8% body weight per day. The highest growth parameters and survival were recorded for control diet. However, the fry fed 10% azolla incorporated diet showed similarities in weight gain %, specific growth rate and feed conversion ratio with control group