Distinct β-glucan molecules modulates differently the circulating cortisol levels and innate immune responses in matrinxã (Brycon amazonicus)

Abstract

This study investigated the effects of two β-glucan molecules with different purities and isolated by different biotechnological processes on the immune response of matrinxã (Brycon amazonicus) prior and after challenge with Aeromonas hydrophila. In this sense, we evaluated serum cortisol and plasma glucose levels, the number of leukocytes (lymphocytes, neutrophils and monocytes), as well as the respiratory activity of leukocytes prior to, 6 and 24 h post infection (hpi). During 15 days, fish were fed with diets containing 0.1% of two β-glucans (β-G 1 and β-G 2, with 71 and 62% of purity, respectively) and then submitted to challenge. Results were compared with a positive control group fed with a β-glucan-free diet. A negative control group, also fed with β-glucan-free diet but inoculated with PBS, was established to evaluate the effect of handling during injection. Our results showed that different β-glucans affected differently the biological responses of matrinxã. The βG 2 modulated the cortisol profile prior to and after the acute infection with A. hydrophila, and increased the mobilization and activity of leukocytes. The infection promoted lymphopenia at 6 hpi and both β-glucans increased the circulating lymphocyte population 24 hpi. Moreover, the β-G 2 prevented the infection-induced neutrophilia at 6 and 24 hpi. Finally, the β-G 2 caused a marked increase in the circulating monocytes prior to infection, and a reduction at 6 hpi that was reversed at 24 hpi. In summary, our study demonstrates that β-G 2 was more efficient on the induction of the cell-mediate immunity in matrinxã.

The Effects of Silkworm-Derived Polysaccharide (Silkrose) on Ectoparasitic Infestations in Yellowtail (Seriola quinqueradiata) and White Trevally (Pseudocaranx dentex)

“…However, it is also possible that the silkrose treatment itself causes a decrease in serum cortisol levels, as the treatment induced a significant decrease in serum cortisol levels even in yellowtail that had not been infected with many parasites. In agreement with the current result, naturally derived polysaccharides, such as those from Astralagus propinquus [53], Ulva intestinalis [54], Gracilariopsis persica [54], as well as β-glucan [55,56], have also been found to be associated with the reduction of serum cortisol level in various teleost species. These previous studies, however, did not establish the underlying mechanism of this cortisol-lowering effect.…”

Synergistic Effect of Dietary Supplementation with Sodium Butyrate, β-Glucan and Vitamins on Growth Performance, Cortisol Level, Intestinal Microbiome and Expression of Immune-Related Genes in Juvenile African Catfish (Clarias gariepinus)

“…This condition, called immunosuppression, increases the susceptibility of the fish body to the development of bacterial and viral infections [50]. The scientific literature contains data confirming the thesis that β-glucan administered with the diet contributes to the reduction in cortisol secretion by intrarenal cells in fish [31,51]. The presented work also confirmed the above thesis.…”

Effects of dietary β-glucans on the productive performance, blood parameters, and intestinal microbiota of angelfish (Pterophyllum scalare) juveniles

“…In the present study, MacroGard ® , a commercial product extracted from S. cerevisiae containing a minimum of 60% β-1,3/1,6-glucans, was the source used. Some studies using the same supplementation concentrations as the present study have demonstrated the effect of dietary yeast β-glucans on the modulation of RBC counts and hemoglobin, lysozyme, total protein, albumin, globulin, total cholesterol, and glucose concentrations (Cao et al 2019, Ghaedi et al 2015, Montoya et al 2018, Talpur et al 2014. Meanwhile, some studies have also reported the lack of effects on hematological, immunological, ED C.S.…”