| Summary: | This study investigated the effects of pyrola (Pyrola calliantha) and common verbena (Verbena officinalis) on the growth performance, biochemical parameters, and non-specific immune responses of the hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu). The fish fed with diets containing common verbena or pyrola powder was incorporated into the basal diet at 0, 20(A2), 40(A4), and 60(A6) g/kg, or 20(B2), 40(B4), and 60(B6) g/kg, respectively, for 60 d. Common verbena significantly improved the growth performance of grouper, especially at the dose of 40 g/kg (p < 0.05). The highest and lowest values of total protein and globulin were found in the B6 and control groups, respectively. Significantly lower low-density lipoprotein cholesterol values were found in the fish fed diets containing 40 and 60 g/kg of the herbs compared with the control (p < 0.05). Aspartate aminotransferase activities were significantly lower in all experimental groups compared to the control, and the B6 group had the lowest value (p < 0.05). Relative to the control, the herbs significantly reduced malondialdehyde level and improved superoxide dismutase activity, catalase activity, and total antioxidant capacity, and the effect was greatest in the B6 group. Relative to the control, the mRNA levels of HSP90, IL-1β, IgM and TRIF genes were significantly up-regulated in all treatment groups throughout the entire experimental period. When challenged with V. alginolyticus LP01, the survival rate of treated groups was significantly (p < 0.05) higher than that of the control, and the B6 group had the highest value. In conclusion, based on growth performance, the optimal supplemental level of common verbena in the hybrid grouper diet was 40 g/kg; with immunity as the evaluation index, the optimal supplemental level of pyrola in the hybrid grouper diet was 60 g/kg. These results provide a theoretical basis for the application of Chinese herbs in healthy culture of grouper.
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