Masculinization in guppy, Poecilia reticulata Peter, 1859 using phytoextracts loaded ZnO nanoparticles

The study offers a sustainable alternative to synthetic hormones for producing all-male Poecilia reticulata using ZnO nanoparticles loaded with Asparagus racemosus (Shatavari) and Withania somnifera (Ashwagandha) extracts. Plant extracts were prepared, analyzed, conjugated with ZnO nanoparticles, and incorporated into feed at various concentrations. Fish were fed the experimental diets for 30 days, using a completely randomized design with eight treatments, including positive and negative controls. The particle size of ZnO nanoparticle, Shatavari loaded ZnO nanoparticle and Ashwagandha loaded ZnO nanoparticle was 6.96 nm (PDI 0.278), 58.00 nm (PDI 0.34) and 52.55 nm (PDI 0.31) respectively. The entrapment efficacy percentage was found to be 48.52% for Shatavari loaded ZnO nanoparticles and 46% for Ashwagandha loaded ZnO nanoparticles. The FT-IR analysis confirmed successful conjugation of the plant extracts with ZnO nanoparticles and the presence of active phytochemicals. The treatment groups showed statistical significance in growth parameters and condition factor compared to the control, with the ZnO nanoparticle treatments exhibiting the best performance. The highest male percentage of 88.87% was recorded in Ashwagandha loaded ZnO nanoparticle at 0.075 mg kg-1 of feed with the survival of 95%. The highest indeterminate guppies of 12.69% were found in treatment containing Shatavari loaded ZnO nanoparticle at 0.15 mg kg-1 of feed, showing delayed sexually dimorphic characters. The treatment groups exhibited higher Gonopodial Index values compared to the control, indicating enhanced development of male traits. These findings suggested that nano-conjugated plant extracts improved masculinization, growth, and survival rates in the fish.