Facile synthesis of haemocyanin-capped zinc oxide nanoparticles: Effect on growth performance, digestive-enzyme activity, and immune responses of Penaeus semisulcatus.

ZnO nanoparticles (NPs) synthesized using haemocyanin (Hc-ZnONPs) purified from haemolymph of Penaeus semisulcatus were characterized using various techniques. HR-TEM and SEM microscopy indicated Hc-ZnONPs had a typical size of 20-50 nm and were spherical. The objective of current investigation was to assess the effects of dietary supplementation of Hc-ZnONPs on the development and activity of digestive and metabolic enzymes, as well as the antioxidant levels in P. semisulcatus. Trial basal diets were supplemented with Hc-ZnONPs at rates of 0, 10, 20, 40, 60, and 80 mg kg-1 (dry feed weight) and were fed to P. semisulcatus for 30 d. For 60 mg kg-1 Hc-ZnONPs-supplemented feed, significantly (P < 0.05) enhanced endurance, development, and activity of the digestive enzyme were observed. The enzymatic antioxidants and metabolic enzymes activities in the muscle exhibited no significant changes when 10-60 mg kg-1 Hc-ZnONPs-supplemented feed was fed to P. semisulcatus. Conversely, feeding the P. semisulcatus with 80 mg kg-1 Hc-ZnONPs produced a harmful outcome, with significant increase in the enzymatic antioxidants and metabolic enzymes. Consequently, 80 mg kg-1 Hc-ZnONPs was identified as lethal to P. semisulcatus. Hence, it is proposed that the diet of P. semisulcatus can be supplemented with up to 60 mg kg-1 Hc-ZnONPs for improving the endurance, development and immunity.