Effect of paprika extracts on growth performance, haemolymph chemistry, intestinal microbiota and antioxidant enzyme activities of white‐leg shrimp (Litopenaeus vannamei)

Abstract This study aims to evaluate the effects of paprika extract on the survival rate, growth performance and stimulation of the innate immune system of Litopenaeus vannamei . In this experiment, 240 healthy shrimp (3.22 ± 0.12 g) were randomly divided into four groups. The shrimp were fed diets with different concentrations of paprika oil extracts (0%, 0.5%, 1% and 2%) for 8 weeks. The results showed that growth performance, urea, uric acid, creatinine, cholesterol levels, aspartate aminotransferase and alkaline phosphatase activities were not significantly affected by adding paprika extract to the shrimp diet ( p > 0.05). Diets containing 1% and 0.5% paprika extract showed the highest levels of total protein and triglyceride, respectively ( p < 0.05). There was a significant decrease in haemolymph glucose concentration in shrimp‐fed diets containing 1% and 2% paprika extract ( p < 0.05). Moreover, a diet containing 0.5% paprika extract resulted in the highest levels of total heamocyte count, hyaline cells and large‐granular cells in shrimp ( p < 0.05). Higher catalase and superoxide dismutase activities were also exhibited in the paprika groups ( p < 0.05). Vibrio sp. bacteria were not significantly reduced by paprika extract in the intestines of L. vannamei ( p > 0.05). A significant decrease in heterotrophic bacteria was observed with increasing extract concentrations ( p < 0.05). The shrimp culture industry can utilize paprika extract as a cost‐effective, efficient and environmentally friendly immune stimulant at a concentration of 0.5%.