Fabrication of chitosan nanoparticles loaded with aromatase inhibitors for the advancement of gonadal development in Clarias magur (Hamilton, 1822)

Aromatase inhibitors (AIs) block the conversion of testosterone to 17β-estradiol and thereby increase the serum testosterone levels. The present work was aimed for development and characterization of nanoconjugated AIs for studying the effect on the gonadal development in Clarias magur. Two AIs such as Fadrozole and Letrozole were used in this study and conjugated with chitosan nanoparticles. The size and zeta potential of the blank chitosan nanoparticles was 47.6 nm and 29 mV, respectively. The size of chitosan conjugated Letrozole (LZC) was 108.9 nm with a zeta potential of 18.9 mV while chitosan conjugated Fadrozole (FZC) showed the size of 150.5 nm with a zeta potential of 25.6 mV. Entrapment efficiency of LZC and FZC were 86.6% and 84.3%, respectively. The FTIR analysis confirmed the conjugation between chitosan and AIs. Fish receiving an intramuscular injection of LZC showed a higher level of serum testosterone than FZC injected fishes. On the other hand, a lower level of 17β-estradiol was observed in LZC treated fish. These results indicate the higher efficiency of letrozole over fadrozole. The oral delivery of Letrozole alone and conjugated with chitosan nanoparticles was carried out through feed (100 mg/kg of feed) to fingerlings. The LZC treated group showed advancement in the testicular development which was evident in serum hormonal analysis, histological examination of gonads and Gonadosomatic Index (GSI). Thus, the nano-formulation developed in the present study may be useful for improving the reproductive output in fish.