Nanoemulsion of coriander oil and Asparagus racemosus extract enhances immunity in Nile tilapia (Oreochromis niloticus).

Abstract

This study aimed to formulate and characterize a novel stable nanoemulsion of coriander oil (CSO) and aqueous root extract of Asparagus racemosus (ARE), nanoCA, and evaluate its efficacy as a prophylactic feed additive in Nile tilapia (Oreochromis niloticus) for improved growth and immunity. The nanoCA was prepared using high-energy homogenization and characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, Raman spectroscopy, and inductively coupled plasma-mass spectrometry (ICP-MS). A 45-day study on Nile tilapia using nanoCA (10, 25, 50 μL/g feed) showed improved growth performance in nanoCA groups compared to subtherapeutic oxytetracycline (OTC, 30 mg/kg) and control groups. Hematological and serological enzymatic, non-enzymatic, and immunological parameters were also modified in nanoCA groups. The liver showed intact cellular morphology with slightly vacuolated hepatocytes, and the kidney appeared healthy with occasional concretions in glomeruli and tubules in the nanoCA group. NanoCA treatment increased the expression of insulin-like growth factor (igf1) and immunoglobulin m (igm), and decreased the expression of tumor necrosis factor (tnfα) and interleukin 1β (il-1β) genes. All nanoCA groups exhibited increased survival during the bacterial challenge compared to the OTC and control groups. As a prophylactic feed additive, nanoCA significantly enhanced fish health by improving growth performance, modulating immune responses, and increasing survival rates during bacterial challenge.