Abstract:Investigation of fecundity and gonado somatic index (GSI) of Rastrelliger kanagurta were carried out from March 2011 to February 2012. Fecundity was determined at different length, weight and ovary ranges of different individual fishes. Study revealed that at 5% significant level significant average absolute fecundity was found to be 1,08,266 and relative fecundity ranged from 407 to 1499. The number of ova generally increased with increase in length and weight. However, variations in fecundity with respect to length and weight were also noticed. The gonado-somatic index (GSI) was calculated for each individual fish (592 numbers) and was averaged for each month. The average GSI values were plotted against each month to analysed monthly variations. GSI showed wide variations between sex and it was highest for both males and females during the month of April and September, showing occurrence of more ripe individuals. Analysis of regression showed that there were significant relationship between the fecundity with the fish length, body weight and ovary weight.

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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.

The aim of this study was to evaluate the effect of letrozole (a non-steroidal aromatase inhibitor) on masculinization of Siamese fighting fish (Betta splendens). Different doses of letrozole 50, 100, 150 and 200 ppm (mg/kg feed) were incorporated into diet and fed for periods of 30, 40 or 50 days. Immersion treatment of letrozole at selected doses (250, 500, 750 and 1,000μg/l) for 3 h each on third, fifth and eighth day-post-hatching (dph) (Trial 1) and fourth, sixth and eighth dph (Trial 2) was given.The oral administration of letrozole for 30, 40 or 50 days did not have any significant effect on the sex ratio of B. splendens. The immersion treatment of letrozole induced 100% masculinization at 500 and 1000μg/l in trial 1, while it yielded only 66.66 and 90% male population at 500 and 1000 μg/l in Trial 2. The dietary administration of letrozole for 30 and 50 days caused tail deformities and/or rudimentary and absence of dorsal fin. The progeny testing of males from letrozole treated (both oral and immersion) groups indicate that the sex ratio of progenies of each of the males tested did not differ significantly from that of control, indicating that all those males carried XY genotype. Letrozole treatments suppressed ovarian development (atretic oocytes were common). However, the testicular development was unaffected. The study revealed that immersion treatment of letrozole was more effective in inducing masculinization of B. splendens than the oral administration of letrozole.

Abstract:The aim of present work was to develop a new Fadrozole (FDZ)-loaded Poly(D,L-lactide-co-glycolide) lactide:glycolide (50:50)(PLGA) nanoparticles for effective delivery of the masculinization drug, Fadrozole, as an alternative to commercially available masculinization agents like testosterone (dietary supplementation of 17α-methyltestosterone) which are steroids and banned in most EU countries. The FDZ-loaded PLGA NPs were prepared by solvent displacement technique. The particle size of FDZ-loaded PLGA NPs was analyzed using LICOMP particle size analyser. It was found to be in the range of 60±66.7 nm to 560±66.7 nm with average size of 201.4±66.7 nm, where the Zeta potential was estimated to be about -20.82 mV, a series of experiments were carried out to induce masculinization using FDZ-loaded PLGA nanoparticles during the sex differentiation period. Tilapia, Oreochromis niloticus fry were treated with FTZ-loaded PLGA nanoparticles at dosages 5, 25, 50 and 100ppm/kg diet for 10, 15 and 30 days. The results indicated an increase in the proportion of males with dosage and duration of treatment. The male percentage was 92.35±0.86 for T7(50 ppm) at 10 days, 97.76±1.12 for T7 (100 ppm) at 15 days and 100 % for both T6 (50ppm) and T7 (100 ppm) at 30 days. This is first time done by using nanotechnology efficiently in Tilapia species which is very important Fresh water aquaculture species in present era. Which showed increase the male population with lesser dose of nano-encapsulated Fadrozole (FDZ)-loaded PLGA nanoparticles drug as compared with naked control Fadrozole (FDZ) drug delivery.