Immunomodulatory effect of potassium diformate and sodium diformate on humoral immunity and antioxidant capacity in Acipenser baerii: Cytokine and high-mobility group protein gene induction

Abstract

The research examined the impact of adding potassium diformate (KDF) and sodium diformate (NDF) to the diet of Siberian sturgeon (Acipenser baerii) and how it influenced their antioxidant levels and immune responses. The fish (n = 315; 17.85 ± 0.2 g initial weight) were fed with seven diets for 56 days, including a control group (unsupplemented diet) and groups with varying levels of KDF (0.15, 0.3, and 0.5%) and NDF (0.15, 0.3, and 0.5%). After the feeding trial, the groups that consumed KDF or NDF demonstrated a dose-responsive elevation in serum superoxide dismutase, catalase, and glutathione peroxidase levels, along with an overall increase in total antioxidant capacity compared to the control group (P < 0.05). These groups also had lower malondialdehyde levels (P < 0.05) and improved immune functions, including higher levels of immunoglobulin M, total protein, albumin, globulin, the activities of lysozyme, respiratory burst, and alternative complement (P < 0.05). Also, the serum bactericidal activity experienced a significant increase (maximum in 0.5% NDF treatment) in the groups subjected to experimental feeding compared to the control group (P < 0.05). The transcription levels of interleukin-1 beta (IL-1β), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-α), high mobility group box 1 (AbHMGB1), and high mobility group box 2 (AbHMGB2) genes in the head kidney were significantly upregulated in fish fed with different doses of KDF or NDF compared to the control group (P < 0.05). The most significant upregulation was observed in the group that received 0.5% NDF. Moreover, the experimental groups demonstrated a lower cumulative mortality rate of the fish following exposure to Aeromonas hydrophila AB005 infection compared to the control group (P < 0.05), with the lowest mortality rate observed in the 0.5% NDF or KDF group. Overall, the results suggest that dietary KDF or NDF, especially 0.5% NDF, are promising as environmentally friendly options and sustainable immunostimulants in Siberian sturgeon aquaculture.