The Effects of Oral Rehmannia glutinosa Polysaccharide Administration on Immune Responses, Antioxidant Activity and Resistance Against Aeromonas hydrophila in the Common Carp, Cyprinus carpio L

Abstract

The effects of the oral administration of Rehmannia glutinosa polysaccharide (RGP-1) on the immunoregulatory properties, antioxidant activity, and resistance against Aeromonas hydrophila in Cyprinus carpio L. were investigated. The purified RGP-1 (250, 500, and 1,000 µg/mL) was co-cultured with the head kidney cells of the common carp. The proliferation and phagocytosis activities of the head kidney cells, and the concentration of nitric oxide (NO) and cytokines in the culture medium were determined. Next, 300 common carps (47.66 ± 0.43 g) were randomly divided into five groups; the two control groups (negative and positive) were administered sterile PBS and the three treatment groups were administered different concentrations of RGP-1 (250, 500, and 1,000 µg/mL) for seven days. Subsequently, the positive and treatment groups were infected with A. hydrophila, and the negative group was administered sterile PBS for 24 h. The concentration of NO, cytokines, lysozyme (LZM), and alkaline phosphatase (AKP) in serum, the total antioxidant capacity (T-AOC), the levels of malonaldehyde (MDA) and glutathione (GSH), and the total activities of superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in the hepatopancreas of the common carp were tested. We observed that RGP-1 could significantly enhance the proliferation and phagocytosis activities (P < 0.05), besides inducing the production of NO, pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-12) and anti-inflammatory cytokines (IL-10, TGF-β) (P < 0.05) in vitro. The in vivo experimental results revealed that RGP-1 significantly enhanced NO production, protein levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-12), LZM and AKP activities, and the antioxidant content (T-AOC, SOD, CAT, GSH, GSH-Px, and MDA) compared to that observed in the negative group prior to A. hydrophila infection (P < 0.05). NO, pro-inflammatory cytokines, LZM Feng et al. RGP-1 as Immunostimulant in Commom Carp and AKP activities were significantly lower than that in the positive group after infection (P < 0.05). However, whether infected or not, the expression of anti-inflammatory cytokines (IL-10, TGF-β) increased significantly in the RGP-1-treated groups (P < 0.05). Therefore, the results suggested that RGP-1 could enhance the non-specific immunity, antioxidant activity and anti-A. hydrophila activity of the common carp, and could be used as a safe and effective feed additive in aquaculture.

Tolerance Assessment of Atractylodes macrocephala Polysaccharide in the Diet of Largemouth Bass (Micropterus salmoides)

“…In the 400 mg/kg AMP supplementation group, the anti-inflammatory cytokine tgfβ was significantly increased, suggesting that AMP could enhance an anti-inflammatory response in largemouth bass. Other polysaccharides, such as Astragalus polysaccharide [ 72 ], Rehmannia glutinosa polysaccharide [ 73 ], and sulphated polysaccharide [ 74 ], also exert anti-inflammatory effects on fish. However, the expression levels of tnfα and nfκb in the liver were increased by 4000 and 8000 mg/kg AMP supplementation, while the iκb and tgfβ mRNA levels were decreased in the present study.…”

Antioxidant Effect of Lactobacillus fermentum CQPC04-Fermented Soy Milk on D-Galactose-Induced Oxidative Aging Mice

“…Based on these findings, our preliminary conclusion is that the antioxidant effect of L. fermentum CQPC04-fermented soy milk on organs or tissues may be related to the synergistic antioxidant capacity of L. fermentum CQPC04, isoflavones, and peptides. Antioxidants, such as Cu/Zn-SOD, Mn-SOD, T-SOD, GSH-Px, CAT, and GSH, play a critical role in defending against free radical damage to the human body (30). In addition, MDA and NO are also critical indicators for evaluating oxidative stress (31).…”

Effect of Dietary Sumac (Rhus coriaria L.) Supplementation on Non-Specific Immune Response and Hematology of Rainbow Trout (Oncorhynchus mykiss), Resistance Against Vibrio anguillarum

“…Nya and Austin (2011) dietary garlic application reduced the mortality rate of A. hydrophila infection compared to control in rainbow trout. Further, Feng et al (2020) reported that dietary administration of Rehmannia glutinosa polysaccharide significantly reduced fish mortality.…”