Effect of the extract of lemon verbena (Aloysia citrodora) on the growth performance, digestive enzyme activities, and immune-related genes in Siberian sturgeon (Acipenser baerii)

Herbal extracts are illustrated as functional substances for sustainable aquaculture. The study evaluated the effects of lemon verbena (LV) extracts (0, 5, 10, and 20 mg/kg) on the performances of the Siberian sturgeon. Fish fed the test diets for eight weeks, then the growth performance and health condition were tested. The results showed enhanced gain weight and specific growth rate in 5, 10, and 20 g/kg groups (P < 0.05) while feed conversion ratio and blood triglycerides were reduced in 10 and 20 mg/kg groups (P < 0.05). Further, fish fed LV at 10 and 20 mg/kg showed improved amylase activity and WBCs (P < 0.05). The counts of red blood cells, hematocrit, hemoglobin, total serum protein, ACH50, total immunoglobulins (Ig), lysozyme (LZM), and respiratory burst activities were increased in fish fed LV at 20 mg/kg (P < 0.05). The skin mucus total protein, total Ig, and LZM were increased in fish fed 20 mg LV/kg (P < 0.05). The relative expression of IL-8, lysozyme, IL-1 beta, and TNF-alpha were upregulated in fish fed LV at 20 mg LV/kg diet. The challenge against Aeromonas hydrophila showed enhanced resistance of Siberian sturgeon by including LV extract. These results revealed that the use of LV extract could improve growth performance and increase the immune response of Siberian sturgeon in the challenge with A. hydrophila.

Automated summary

Herbal extracts, specifically lemon verbena extracts, were found to have positive effects on the growth performance and immune response of Siberian sturgeon, enhancing their resistance against challenges such as Aeromonas hydrophila.