The influence of diet supplementation with turmeric (TUR), curcumin (CUR) and nanoencapsulated curcumin (NMC) was evaluated on haemolymph biochemical parameters and hepatopancreas antioxidant enzymes of Penaeus vannamei (2.96 ± 0.10 g) exposed to low and high salinity stress at 5 and 55 g L−1 respectively. Nine dietary groups containing different dosages (g kg−1 diet) of TUR (TUR 2.5, TUR 5 and TUR 10), CUR (CUR 0.075, CUR 0.150 and CUR 0.300) and NMC (NMC 0.075, 0.150 and 0.300) along with the control group made the ten treatments. After nine weeks of feeding, CUR additives decreased the haemolymph triglycerides, cholesterol, glucose and cortisol in shrimps under normal and stress conditions compared with the control group; the lowest and highest values were observed in NMC 0.150 and control group respectively (p < 0.05). Adding TUR, CUR and NMC supplements to the diet increased total protein, total haemocytes count and differential haemocytes count in stressed and non-stressed shrimps; the highest was observed in NMC 0.150. The lowest and highest activities of antioxidant enzymes including CAT, SOD and GSH-Px before and after the salinity stress were detected in control group and NMC 0.150 respectively (p < 0.05). After the salinity stress, the experimental treatments increased the survival rate, where NMC 0.150 caused the highest survival (p < 0.05). In conclusion, different forms of dietary CUR improved antioxidant capacity and resistance of P. vannamei to acute salinity stress. Nanomicellar carriers in shrimp nutrition can promote immunity and antioxidant responses under stressful conditions through more efficient delivery of dietary immunostimulants.
