Dietary Astragalus polysaccharides enhance potency of inactivated Pseudomonas plecoglossicida vaccine in large yellow croaker (Larimichthys crocea)

Yueyang Song; Hui Chen; Huimin An; Yongyang Wang; Jianchun Shao; Meijiao Yan; Jingqun Ao; Xinhua Chen; Weini Zhang

doi:10.1016/j.fsi.2024.110107

Dietary Astragalus polysaccharides enhance potency of inactivated Pseudomonas plecoglossicida vaccine in large yellow croaker (Larimichthys crocea)

Fish Shellfish Immunol. 2025 Jan 1:157:110107. doi: 10.1016/j.fsi.2024.110107. Online ahead of print.

Authors

Yueyang Song¹, Hui Chen¹, Huimin An¹, Yongyang Wang¹, Jianchun Shao¹, Meijiao Yan¹, Jingqun Ao¹, Xinhua Chen², Weini Zhang³

Affiliations

¹ State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China.
² State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, PR China. Electronic address: chenxinhua@tio.org.cn.
³ State Key Laboratory of Mariculture Breeding, Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China; University Key Lab for Integrated Chinese Traditional and Western Veterinary Medicine and Animal Healthcare in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China. Electronic address: zhangweini@fafu.edu.cn.

PMID: 39753156
DOI: 10.1016/j.fsi.2024.110107

Abstract

Dietary Astragalus polysaccharides (APS) get wide application in aquaculture due to their excellent immunoregulatory effects. However, little is known about the effects of dietary APS on vaccine potency in fish. In the present study, large yellow croakers (Larimichthys crocea) were injected with formalin-inactivated Pseudomonas plecoglossicida after APS feeding for 14 d and then challenged by live P. plecoglossicida on 28 d post-vaccination. The results showed that dietary APS combined with inactivated vaccine could improve the survival rate, and alleviate splenic lesions and bacteria load post-challenge, thus exhibiting a better protection in large yellow croaker against P. plecoglossicida infection than inactivated vaccine treatment alone. Fish in APS + P. plecoglossicida vaccine group expressed a better antioxidant status by possessing a relatively higher serum total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity and a significantly lower malondialdehyde (MDA) content than those in vaccine alone group. Serum lysozyme (LZM) and alkaline phosphatase (AKP) activities, and immunoglobulin M (IgM) titers were all improved in fish of APS + P. plecoglossicida vaccine group compared to fish in vaccine group. Furthermore, fish in APS + P. plecoglossicida vaccine group showed a lower down-regulation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-6, and a higher up-regulation of anti-inflammatory cytokine IL-10, immunoglobulin (IgM) and T cell immunity-related cytokines, interferon-γ (IFN-γ), IL-4/13A, and IL-4/13B, when compared with those in fish of vaccine group. These results suggested that dietary APS could assist inactivated vaccine to trigger stronger innate and adaptive immune responses against P. plecoglossicida infection. These findings further uncover the immunoregulatory mechanism of dietary APS, and provide valuable information for prevention and control of bacteriosis in fish.

Keywords: Astragalus polysaccharides; Immune response; Inactivated vaccine; Large yellow croaker (Larimichthys crocea); Pseudomonas plecoglossicida.