Immunomodulatory effects of dietary β-glucan in silver catfish (Rhamdia quelen)

Abstract

RESUMO.-[Efeito imunomodulador da β-glucana usada como aditivo alimentar em jundiás (Rhamdia quelen).]O uso da β-glucana como suplemento alimentar foi avaliado em jundiás. A β-glucana foi adicionada à ração na proporção de 0.01%, e 0.1% e fornecida aos peixes por 21, para avaliar dados hematológicos e parâmetros do sistema imune natural, ou 42 dias, para avaliar ganho de peso e resistência ao desafio com Aeromonas hydrophila. A adição da β-glucana na dieta não afetou o ganho de peso e não induziu alterações hematológicas nem alterações nos níveis de aglutininas e mieloperoxidase sanguínea. No entanto, a atividade hemolítica natural do sistema do complemento foi significativamente maior nos peixes alimentados com β-glucana. Além disso, nos peixes alimentados com β-glucana e desafiados com A. hydrophila, o número de bactérias isoladas do sangue foi significativamente menor, e a sobrevivência ao desafio foi significativamente maior do que nos peixes que não receberam β-glucana. Consequentemente, concluímos que a β-glucana tem potencial imunomodulador quando adicionada à dieta, nas condições experimentais aqui indicadas, e contribui para aumentar imunidade natural e a resistência dos jundiás ao desafio com patógenos específicos. INTRODUCTIONThe occurrence of infectious diseases is one of the major causes of losses in modern aquaculture (Sitjà-Bobadilla The immunomodulatory effects of dietary β-glucan were evaluated in silver catfish. β-glucan was added to the diet (0.01%, and 0.1%) and fed to the fish for 21 days, to evaluate effects on blood and some innate immune parameter, or fed for 42 days, to evaluate growth rate and resistance to challenge with pathogenic Aeromonas hydrophila. We found that adding β-glucan to the diet had no effect on fish growth and no effect on blood cells, or serum bacterial agglutination and serum myeloperoxidase activity. However, fish that received β-glucan in the diet had the natural hemolytic activity of complement significantly higher compared to control fish. Furthermore, fish fed with β-glucan and challenged with A. hydrophila had fewer bacteria in blood and presented a significantly higher survival rate compared to control fish. Thus, we concluded that β-glucan might be explored as feed additive aiming to improve silver catfish innate immunity and resistance to specific pathogen.INDEX TERMS: Silver catfish, Rhamdia quelen, fish, immunostimulants, β-glucan, Aeromonas hydrophila.

β-Glucans Production of Saccharomyces cerevisiae by Using Tofu Waste as Animal Feed Supplement

“…β-Glucans is extracted using NaOH with the help of heat, then it is precipitated in ethanol to obtain rough β-Glucans.β-Glucans is known to have antimicrobial and antitumor activity by increasing host immune function, and activating macrophages and neutrophils by binding to β-Glucans receptors (Yuan et al 2019). β-Glucans is also reported to have various immune system stimulation activities that are influenced by its structure such as molecular weight, degree of branching, and its conformation (Ho et al, 2016;Dietrichet al 2011;Di Domenico et al, 2017).The primary structure of β-Glucans macromolecule is presented in Figure 2 below.…”

Development of Fish Immunity and the Role of β-Glucan in Immune Responses

“…Similar results were found in case of juvenile pompano ( Trachinotus ovatus ), where the effects of β-glucan feeding to healthy individuals were small, but after infection with Streptococcus iniae , β-glucan offered significant protection [ 138 ]. A model of silver catfish ( Rhamdia quelen ) and Aeromonas hydrophila infection offered similar results [ 139 ]. In general, these studies demonstrated a lack of β-glucan effects when fish are in resting and a significant and positive effect when fish are exposed to a disturbance in the homeostasis, usually by stimuli such as stress [ 140 ], immunological challenges by pathogens [ 137 , 138 ] or chemicals (“immunocompromised”) [ 141 ].…”

The potential benefits of dietary β‐glucan against growth retardation, immunosuppression, oxidative stress and expression of related genes and susceptibility to Aeromonas hydrophila challenge in Oreochromis niloticus induced by herbicide pendimethalin

“…PMN exposed tilapia exposed reduction of immune reaction aspects could be as immunosuppressive effect of PMN (Danion et al., 2012). Enhancement of these immune aspects in tilapia supplemented with βG could be due to immunomodulating action on aquaculture (Domenico et al., 2017; Meena et al., 2013; Vetvicka et al., 2013).…”