Dietary mannan oligosaccharides strengthens intestinal immune barrier function via multipath cooperation during Aeromonas Hydrophila infection in grass carp (Ctenopharyngodon Idella)

Abstract

In recent years, mannose oligosaccharide (MOS) as a functional additive is widely used in aquaculture, to enhance fish immunity. An evaluation of the effect of dietary MOS supplementation on the immune barrier function and related signaling molecules mechanism of grass carp (Ctenopharyngodon idella) was undertaken in the present study. Six diets with graded amounts of MOS supplementation (0, 200, 400, 600, 800, and 1000 mg/kg) were fed to 540 grass carp over 60 days. To examine the immune response and potential mechanisms of MOS supplementation on the intestine, a challenge test was conducted using injections of Aeromonas hydrophila for 14 days. Results of the study on the optimal supplementation with MOS were found as follows (1) MOS enhances immunity partly related to increasing antibacterial substances content and antimicrobial peptides expression; (2) MOS attenuates inflammatory response partly related to regulating the dynamic balance of intestinal inflammatory cytokines; (3) MOS regulates immune barrier function may partly be related to modulating TLRs/MyD88/NFκB and TOR/S6K1/4EBP signalling pathways. Finally, the current study concluded that MOS supplementation could improve fish intestinal immune barrier function under Aeromonas hydrophila infected conditions.

Effects of β-mannanase supplementation on intestinal health and growth of nursery pigs

“…Firstly, by promoting the growth of beneficial bacteria, mannan oligosaccharides may suppress harmful bacteria that trigger the activation of intestinal immune cells, subsequently reducing inflammatory cytokines ( Yang et al., 2021 ). Additionally, by enhancing intestinal barrier function, mannan oligosaccharides may prevent the infiltration of pathogenic bacteria and their toxins into the circulatory, leading to a potential decrease in reducing the activation of immune cells, especially B lymphocytes for immunoglobulin production ( Kim et al., 2016 ; Yang et al., 2021 ; Lu et al., 2022 ). According to Lu et al.…”

“…Additionally, by enhancing intestinal barrier function, mannan oligosaccharides may prevent the infiltration of pathogenic bacteria and their toxins into the circulatory, leading to a potential decrease in reducing the activation of immune cells, especially B lymphocytes for immunoglobulin production ( Kim et al., 2016 ; Yang et al., 2021 ; Lu et al., 2022 ). According to Lu et al. (2022) , the recognition of mannan oligosaccharides as pathogen-associated molecular patterns by immune cells can effectively suppress immune responses by reducing the production of cytokines and immunoglobulins.…”

Effect of Enterocytozoon hepatopenaei on Richness of Gut Bacterial Community in Exopalaemon carinicauda

“…Healthy intestinal ora can produce substances bene cial to the host (Morowitz et al, 2011), and when the intestinal ora is disturbed, the nutrient absorption and immune response of the organism are reduced, thus suffering from secondary bacterial infections (Butt & Volkoff, 2019). For example, abnormal proliferation of Aeromonas punctata in the intestinal tract of grass carp can lead to bacterial enteritis (Lu et al 2022); excessive intestinal Vibrio tubiashii and Vibrio harveyi in shrimp can lead to shrimp white fecal syndrome (Dai et al, 2018). Crustaceans do not have a speci c immune system and rely mainly on nonspeci c immunity to resist environmental stress and pathogenic attack (Smith et al 1992), therefore, intestinal ora plays a rather important role in the growth and development of shrimp (Rungrassamee et al 2016).…”

Effects of Dietary Mannan Oligosaccharides on Growth, Nonspecific Immunity and Tolerance to Salinity Stress and Streptococcus iniae Challenge in Golden Pompano, Trachinotus ovatus

“…The beneficial effects of dietary MOSs have been reported in many aquaculture species, including improved growth performance of Asian Catfish (Clarias batrachus) [24], grass carp (Ctenopharyngodon Idella) [25], while significantly effect was found in tilapia (Oreochromis niloticus × O. aureus) [26], Gulf sturgeon Acipenser oxyrinchus desotoi [27], and gilthead sea bream (Sparus aurata) [28]. In addition, dietary MOS supplementation could boost immune responses in milkfish (Chanos chanos) [29] and hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscogutta-tus♀) [30], while MOS did not affect immune response.…”

“…Moreover, intestinal microorganisms improve in Nile tilapia (Oreochromis niloticus) fed MOS diet [17]. Furthermore, MOS supplemented diet could enhance resilience to stressors in grass carp (Ctenopharyngodon idella) challenged with Aeromonas hydrophila [25]. According to Xue et al [31], the effect of MOS on fish growth depends on species and developmental stage.…”