Radiation Synthesis of Silver Nanoparticles Stabilized in Oligochitosan/Oligo-β-Glucan with High Antioxidant and Antibacterial Effects Against Poultry Pathogens

This study reports the green synthesis of silver nanoparticles (AgNPs) stabilized in mixtures of oligochitosan and oligo-β-glucan (AgNPs@OCTS+OβGC) via gamma irradiation. UV-Vis spectra showed surface plasmon resonance bands at 406–423 nm. TEM showed spherical nanoparticles of 10.2–14.7 nm, depending on the OCTS/OβGC ratio. DLS showed monomodal distributions (Z-average 36.4–46.1 nm; PDI 0.227–0.260), and the zeta potential of AgNPs@OCTS+OβGC rose from +7.6 to +42.5 mV with OCTS content. FTIR spectra were consistent with the participation of amino- and oxygen-containing groups of the OCTS/OβGC matrix in AgNP stabilization. EDX confirmed silver, and XRD revealed face-centered cubic metallic silver. OCTS-rich formulations showed stronger antibacterial activity against Staphylococcus aureus, Escherichia coli, and Salmonella enterica (inhibition zones up to 21.33 mm; MIC 3.91–7.81 µg.Ag.mL−1), while OβGC-rich formulations showed stronger antioxidant activity (IC50 3.09 µg.Ag.mL−1 for ABTS and 3.49 µg.Ag.mL−1 for DPPH). AgNPs@OCTS5+OβGC5 had the highest desirability index (D = 0.76): it retained the MIC values of the OCTS-only sample with improved antioxidant activity and remained stable for six months at 25 °C. These in vitro results support further evaluation of radiation-synthesized AgNPs@OCTS+OβGC against poultry-associated bacteria, including safety and in vivo efficacy studies.