Reverse-gavage feeding as a novel administration to investigate the immunomodulatory effects of Radix Scutellaria water extract on Macrobrachium rosenbergii immunity

The application of herbal medicine is one of the world’s most ancient approaches to treating diseases. This study aimed to examine the immunomodulatory effect of Radix Scutellariae water extract (RSWE) on the Macrobrachium rosenbergii immunity by reverse gavage feeding (RGF). In this study, M. rosenbergii was administered RSWE by RGF to stimulate its immunity. Furthermore, total hemocyte count (THC), phenoloxidase (PO), respiratory burst (RB), transglutaminase (TG), and lysozyme activity in hemocytes were evaluated to determine the immunological responses. Meanwhile, midgut and hepatopancreas were isolated to observe immune-related genes (LGPB, PE, and proPO). The study employed four treatments (0, 1, 5, and 10 µg of RWSE), and each treatment consisted of 3 replications. All data were analyzed using SPSS 17.0 (one-way ANOVA and Duncan test) to evaluate the differences among treatments. The results showed that the 5 µg RSWE was the optimum dosage to enhance the immune responses and induce the expression of immune-related genes in the hepatopancreas and midgut of M. rosenbergii. Finally, the RGF method can be used to investigate the immunomodulatory effect of RSWE on prawn, and the immune response associated with each dose can be compared precisely.