Beta-glucan: an ideal immunostimulant in aquaculture (a review).
TL;DR: This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β- glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes.
Abstract: The major hindrance in the development and sustainability of aquaculture industry is the occurrence of various diseases in the farming systems. Today, preventive and management measures are central concern to overcome such outbreak of diseases. Immunostimulants are considered as an effective tool for enhancing immune status of cultured organisms. Among different immunostimulants used in aquaculture practices, β-glucan is one of the promising immunostimulant, which is a homopolysaccharide of glucose molecule linked by the glycoside bond. It forms the major constituents of cell wall of some plants, fungi, bacteria, mushroom, yeast, and seaweeds. Major attention on β-glucan was captivated with the gain in knowledge on its receptors and the mechanism of action. The receptor present inside the animal body recognizes and binds to β-glucan, which in turn renders the animal with high resistance and enhanced immune response. This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β-glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes. Study also summarizes the effect of β-glucan on its receptors, recognition of proteins, immune-related enzymes, immune-related gene expression and their mechanisms of action.
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496 citations
TL;DR: This review of immunostimulants primarily focuses on their protective efficacies and on what is known concerning their effects on the immune systems of aquatic organisms when delivered in vivo.
Abstract: Similar to other industries, aquaculture constantly requires new techniques to increase production yields. Modern technologies and different scientific fields, such as biotechnology and microbiology, provide important tools that could lead to a higher quality and a greater quantity of products. New feeding practices in farming typically play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. As ‘bio-friendly agents’, immunostimulants, such as biological factors, probiotics and vitamins, can be introduced into the culture environment to control and kill pathogenic bacteria, as well as to promote growth of the cultured organisms. In addition, immunostimulants are non-pathogenic and non-toxic and do not produce undesirable side effects when administered to aquatic organisms. In this review, we summarize previous studies performed with both traditional immunostimulants and the most promising new generation of immunostimulants, such as polysaccharides, nutrients, oligosaccharides, herbs, microorganisms, prebiotics and different biological factors. This review primarily focuses on their protective efficacies and on what is known concerning their effects on the immune systems of aquatic organisms when delivered in vivo.
254 citations
TL;DR: The recent advancement in aquaculture probiotics research and its impact on fish health, nutrition, immunity, reproduction and water quality is summarized.
188 citations
TL;DR: This review highlights the classifications and applications of probiotics in Aquaculture, and summarizes the advancement and research highlights of the probiotic status and mode of action, which are of great significance from an ecofriendly, sustainable, intensive aquaculture point of view.
Abstract: Aquaculture is emerging as one of the most viable and promising enterprises for keeping pace with the surging need for animal protein, providing nutritional and food security to humans, particularly those residing in regions where livestock is relatively scarce. With every step toward intensification of aquaculture practices, there is an increase in the stress level in the animal as well as the environment. Hence, disease outbreak is being increasingly recognized as one of the most important constraints to aquaculture production in many countries, including India. Conventionally, the disease control in aquaculture has relied on the use of chemical compounds and antibiotics. The development of non-antibiotic and environmentally friendly agents is one of the key factors for health management in aquaculture. Consequently, with the emerging need for environmentally friendly aquaculture, the use of alternatives to antibiotic growth promoters in fish nutrition is now widely accepted. In recent years, probiotics have taken center stage and are being used as an unconventional approach that has numerous beneficial effects in fish and shellfish culture: improved activity of gastrointestinal microbiota and enhanced immune status, disease resistance, survival, feed utilization and growth performance. As natural products, probiotics have much potential to increase the efficiency and sustainability of aquaculture production. Therefore, comprehensive research to fully characterize the intestinal microbiota of prominent fish species, mechanisms of action of probiotics and their effects on the intestinal ecosystem, immunity, fish health and performance is reasonable. This review highlights the classifications and applications of probiotics in aquaculture. The review also summarizes the advancement and research highlights of the probiotic status and mode of action, which are of great significance from an ecofriendly, sustainable, intensive aquaculture point of view.
181 citations
TL;DR: The potential of long chain beta-glucans to serve as novel prebiotics based on current knowledge on their sources, preparation, fermentation characteristics, and the plausible mechanisms involved in their utilization are discussed.
136 citations
References
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TL;DR: New insights into innate immunity are changing the way the way the authors think about pathogenesis and the treatment of infectious diseases, allergy, and autoimmunity.
10,685 citations
"Beta-glucan: an ideal immunostimula..." refers background in this paper
...These type I transmembrane receptors identify microbial conserved structures or pathogen-associated molecular patterns (PAMPs)....
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...This phenomenon is called as pathogen-associated molecular patterns (PAMPs)....
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...Various kinds of substances have been used and their suitability as immunostimulant has been studied, but only few of them are found suitable for use in aquaculture (Raa et al.1992; Siwicki et al. 1998)....
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...LRRs are responsible for the recognition of PAMPs (Akira et al. 2006)....
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TL;DR: By combining the rationale of pro- and prebiotics, the concept of synbiotics is proposed to characterize some colonic foods with interesting nutritional properties that make these compounds candidates for classification as health-enhancing functional food ingredients.
Abstract: Because the human gut microbiota can play a major role in host health, there is currently some interest in the manipulation of the composition of the gut flora towards a potentially more remedial community. Attempts have been made to increase bacterial groups such as Bifidobacterium and Lactobacillus that are perceived as exerting health-promoting properties. Probiotics, defined as microbial food supplements that beneficially affect the host by improving its intestinal microbial balance, have been used to change the composition of colonic microbiota. However, such changes may be transient, and the implantation of exogenous bacteria therefore becomes limited. In contrast, prebiotics are nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacterial species already resident in the colon, and thus attempt to improve host health. Intake of prebiotics can significantly modulate the colonic microbiota by increasing the number of specific bacteria and thus changing the composition of the microbiota. Nondigestible oligosaccharides in general, and fructooligosaccharides in particular, are prebiotics. They have been shown to stimulate the growth of endogenous bifidobacteria, which, after a short feeding period, become predominant in human feces. Moreover, these prebiotics modulate lipid metabolism, most likely via fermentation products. By combining the rationale of pro- and prebiotics, the concept of synbiotics is proposed to characterize some colonic foods with interesting nutritional properties that make these compounds candidates for classification as health-enhancing functional food ingredients.
7,232 citations
"Beta-glucan: an ideal immunostimula..." refers background in this paper
...Prebiotics are non-digestible feed ingredients that benefit the host by stimulating growth and activity of beneficial bacteria in gastrointestinal (GI) tract (Gibson and Roberfroid 1995)....
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TL;DR: This review focuses on the functions of PRRs in innate immunity and their downstream signaling cascades and identifies cytoplasmic PRRs to detect pathogens that have invaded cytosols.
Abstract: The innate immune system is an evolutionally conserved host defense mechanism against pathogens. Innate immune responses are initiated by pattern recognition receptors (PRRs), which recognize specific structures of microorganisms. Among them, Toll-like receptors (TLRs) are capable of sensing organisms ranging from bacteria to fungi, protozoa, and viruses, and play a major role in innate immunity. However, TLRs recognize pathogens either on the cell surface or in the lysosome/endosome compartment. Recently, cytoplasmic PRRs have been identified to detect pathogens that have invaded cytosols. In this review, we focus on the functions of PRRs in innate immunity and their downstream signaling cascades.
2,049 citations
"Beta-glucan: an ideal immunostimula..." refers background in this paper
...Recently, cytoplasmic PRRs have been identified to detect pathogens that have invaded cytosols (Uematsu and Akira 2006)....
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TL;DR: Innate immunity has been considered only to provide rapid, incomplete antimicrobial host defense until the slower, more definitive acquired immune response develops but may have an additional role in determining which antigens the acquired immune system responds to and the nature of that response.
Abstract: Innate immunity has been considered only to provide rapid, incomplete antimicrobial host defense until the slower, more definitive acquired immune response develops. However, innate immunity may have an additional role in determining which antigens the acquired immune system responds to and the nature of that response. Knowledge of the molecules and pathways involved may create new therapeutic options for infectious and autoimmune diseases.
1,812 citations
"Beta-glucan: an ideal immunostimula..." refers background in this paper
...Lipopolysaccharide and b-glucan binding protein (LGBP) Pattern recognition proteins (PRPs) recognize common epitopes present on the surface of invading pathogen and are generally carbohydrate moieties (Fearon and Locksley 1996)....
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...Pattern recognition proteins (PRPs) recognize common epitopes present on the surface of invading pathogen and are generally carbohydrate moieties (Fearon and Locksley 1996)....
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TL;DR: The innate immune system is the only defence weapon of invertebrates and a fundamental defence mechanism of fish and plays an instructive role in the acquired immune response and homeostasis and is therefore equally important in higher vertebrates.
1,801 citations
"Beta-glucan: an ideal immunostimula..." refers background in this paper
...Immunostimulants and their biological effects pertaining to fish larval aquaculture were explained by Bricknell and Dalmo (2005), whereas Magnadóttir (2006) gave an overview of the ontogenic development of non-specific immune system with respect to different innate factors influenced by…...
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...Beta-glucan: an ideal immunostimulant in aquaculture (a review)...
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