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.

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.