Date palm seed nanoparticles induce multiorgan histomorphological remodeling and immune-associated cellular responses...

Plant-derived nanoparticles have attracted increasing attention as potential sustainable feed additives in aquaculture, owing to their bioactive properties and potential to influence tissue-level responses and physiological processes. This study evaluated the effects of dietary date palm seed nanoparticles (DPS-NPs) on the histomorphometric characteristics of multiple organs in Nile tilapia (Oreochromis niloticus). DPS-NPs were synthesized by acid hydrolysis and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). TEM revealed well-dispersed spherical nanoparticles ranging from 24 to 100 nm. A total of 144 Nile tilapia were randomly assigned to four dietary groups, with three replicate tanks per group and 12 fish per tank. Under controlled laboratory conditions, the subjects were fed diets containing dietary DPS-NPs at concentrations of 0, 40, 80, or 120 mg/kg diet over a 30-day feeding trial. Tissue samples from the spleen, liver, kidney, intestine, and skeletal muscle were examined via light microscopy, and quantitative morphometry was performed using ImageJ/Fiji software. Histological analysis revealed dose-dependent improvements across all organs. The liver showed enhanced hepatic cord organization, reduced cytoplasmic vacuolization, and an increased density of Kupffer-like cells, while melanomacrophages proliferated markedly in the spleen, liver, and kidney. Telocyte-like interstitial cells were consistently observed near hepatic vasculature. The intestinal mucosa exhibited goblet cell hyperplasia, improved villus architecture, and muscularis thickening at higher doses. Skeletal muscle showed better myofibrillar organization, clear sarcomere banding, and increased eosinophilic staining intensity, suggestive of higher myoglobin content. Overall, dietary DPS-NPs, particularly at 120 mg/kg diet, were associated with morphological changes consistent with immune-cell recruitment and tissue remodeling across multiple organ systems, supporting further investigation of date palm seed waste as a functional ingredient in sustainable aquaculture nutrition.