Dietary effects of soybean products on gut microbiota and immunity of aquatic animals: A review

Abstract

Soybean meal (SBM) is one of the most commonly used vegetable ingredient to replace fish meal in fish diets. However, SBM is limiting in some essential amino acids and contains numerous antinutritional factors and antigens that can affect intestinal microbiota and innate immune system in several finfish species and crustaceans and compromise health. The impact of SBM on health and gut microbiota of aquatic animals is not only affected by SBM in general, but also on the degree of treatment of the meal and exposure. Recently, many studies are actively seeking ways to complement or balance those adverse responses induced by high inclusion of SBM in aquaculture diets. These include advanced processing and mixture of feed with other feed components to balance antinutritional factors. The impact of dietary soybean oil on gut microbiota has also been investigated but to a lesser extent than SBM. As the gastrointestinal tract has been suggested as one of the major routes of infection in finfish species and crustaceans, the effect of soybean products on the gut microbiota is important to investigate. Several studies have focus on supplementation of SBM on the adverse responses of the innate immune system as immunological mechanisms are likely involved in the underlying pathology. However, the precise cause of the inflammatory process has not yet been clarified, even though some investigations have suggested that alcohol‐soluble antinutritional factors, especially soy saponins, are potential causative factors. Possible interactions between soybean products and innate immune system in several finfish species and crustaceans are discussed.

Administration of host‐derived probiotics does not affect utilization of soybean meal enriched diets in juvenile turbot (Scophthalmus maximus)

“…Typically the onset of SBM‐induced enteritis is accompanied by alterations of the microvilli and mucosal folds. These changes often induce a perceptible shift in the autochthonous bacteria community (Bai et al, ; Dawood et al, ; Merrifield et al, ; Zhou et al, ). In conclusion, it seems plausible that also the colonization process of the applied probiotic isolates is thereby comprehensively impeded.…”

“…However, the utilization of fishmeal is becoming increasingly restricted. Vast overfishing and a growing demand in animal nutrition led to an alarming scarcity and consequently a drastic increase in costs (Henry, Gasco, Piccolo, & Fountoulaki, 2015;Tacon & Metian, 2008;Zhou, Ringø, Olsen, & Seong, 2018). Thus, the exploration of new sources of feedstuff to promote a cost-efficient and a sustainable production of aquatic animals is the major challenge for the growing aquaculture industry (Henry et al, 2015;Olsen & Hasan, 2012).…”

Dietary taurine supplementation to a plant protein source‐based diet improved the growth and intestinal immune function of young grass carp (Ctenopharyngodon idella)

“…In general, cytokines consist of pro‐inflammatory cytokines (e.g., IFN‐γ, IL‐1β, IL‐8, IL‐15 and IL‐17D) and anti‐inflammatory cytokines (e.g., TGF‐β, IL‐4, IL‐10 and IL‐11) in fish (Song et al, ; Zhou, Ringø, Olsen, & Song, ). A previous study found that taurine could down‐regulate IL‐1β and IL‐10 mRNA levels in the intestines of European sea bass (Rimoldi et al, ).…”

Dietary citric acid supplementation alleviates soybean meal-induced intestinal oxidative damage and micro-ecological imbalance in juvenile turbot,Scophthalmus maximusL

“…In addition, protein kinase C (PKC) could mediate influence of oxidative stress on epithelial mucus secretion, probably through triggering PI3K and MAPK pathways (El Homsi et al, 2007;Lee, Crawley, Hokari, Kwon, & Kim, 2010). The intestinal microbiota serves as a primary stimulus for shaping and modulating intestinal function (Ringø et al, 2016;Zhou, Ringø, Olsen, & Song, 2017). However, the antigenic nature of indigenous bacteria and the sensitive nature of host cells contribute to a precarious relation under stress conditions, which could alter intestinal function and disease susceptibility (Collins & Bercik, 2009).…”