NANOENCAPSULATION OF NEEM AND FENUGREEK EXTRACTS: A NOVEL APPROACH TO IMPROVE BIOAVAILABILITY IN FISH DISEASE TREATMENT

Bacterial infections remain a serious threat to ornamental fish aquaculture, especially goldfish (Carassius auratus), which are highly valued for their aesthetic and commercial importance. Among the major pathogens, Aeromonas hydrophila, Pseudomonas fluorescens, and Edwardsiella tarda cause diseases such as hemorrhagic septicemia, fin rot, and edwardsiellosis, often leading to severe economic losses. Conventional reliance on antibiotics like ampicillin and tetracycline, though effective, has led to antibiotic resistance, environmental concerns, and consumer preference for residue-free fish, driving the search for natural alternatives. This study investigated the antibacterial properties of neem (Azadirachta indica) and fenugreek (Trigonella foenum-graecum) extracts against common fish pathogens. Extracts were prepared using cold maceration in 70% ethanol and tested via the Kirby-Bauer disc diffusion method at concentrations of 100, 200, and 400 mg/mL. Neem extract showed strong, dose-dependent antibacterial activity against A. hydrophila, producing inhibition zones of 12.3–21.4 mm due to its bioactive compounds like azadirachtin, nimbin, and nimbidin. Fenugreek extract exhibited moderate inhibition (7.2–12.8 mm), while antibiotics produced larger zones (e.g., ampicillin 25.6 mm). In vivo evaluation with 35 goldfish further validated these findings. Neem extract at 1.0 g/L achieved 60% survival, fenugreek extract 40%, and a neem-fenugreek combination 50%. Antibiotics outperformed herbal treatments, with ampicillin and tetracycline yielding 80% and 70% survival, respectively, compared to only 20% in untreated controls. Overall, neem extract demonstrated promising potential as a natural therapeutic option to reduce dependence on antibiotics in aquaculture. Further research is recommended to optimize dosages, assess long-term safety, and extend applications to other fish species for sustainable disease management.