Immunomodulatory effects of β‐glucans derived from Euglena gracilis or Saccharomyces cerevisiae for hybrid striped bass ( Morone chrysops  ×  M. saxatilis )

Abstract

Beta-glucans (BGs) can activate the animal's innate immune system, enhancing the primary defence lines against pathogenic insults. The objective of this study was to assess the immune responses of hybrid striped bass (HSB) when exposed to paramylon, derived from Euglena gracilis, or zymosan, derived from Saccharomyces cerevisiae. Two separate trials were conducted to evaluate the efficacy of these immunostimulants as a feed additive or injected intraperitoneally. Five diets were formulated to contain either paramylon or zymosan at two different levels (50 or 100 mg/kg), and no supplementation serving as the control. Blood and head kidney were sampled, and an elevated production of anion superoxide from isolated phagocytes was observed for all supplemented groups when compared to the control. Dietary paramylon at 50 mg/ kg increased immunoglobulin levels in the plasma. The second trial was conducted by injecting a BG solution (10 mg of β-glucan kg -1 of body weight) and phosphate buffer solution serving as the control. Seven days after injection, blood samples were collected and immunological profiles from whole blood and plasma were significantly (p < .05) affected by the treatments. The results from this study indicate that both dietary and injected paramylon and zymosan modulated the immunological responses of HSB.

Alleviating effects of β‐glucan inOreochromis niloticuson growth performance, immune reactions, antioxidant, transcriptomics disorders and resistance toAeromonas sobriacaused by atrazine

“…As an example, β-glucan protect DNA from oxidative damage by scavenging oxygen and hydroxyl radicals (Bashir & Choi, 2017). In fish culture, βG is acknowledged as an immunostimulant that is able to boost the immune response of numerous aquatic animals, such as Cyprinus carpio (Pionnier, Falco, Miest, Shrive, & Hoole, 2014), Pagrus auratus (Cook, Hayball, Hutchinson, Nowak, & Hayball, 2003), Oncorhynchus mykiss (Ji, Fu, Sun, Li, & Liu, 2019) and striped bass (Yamamoto, Castillo, & Gatlin, 2019).…”

Future feed resources in sustainable salmonid production: A review

“…227 Other health-promoting biomolecules from microalgae include beta 1,3-glucans, such as from Chlorella strains and Euglena gracilis, which can activate the immune system of various fish species. [228][229][230] Different microalgae-based products, such as dried whole cells, ruptured cells, defatted cells (after lipid extraction) and extracts from various microalgal species, have been studied in feeding trials over the last decade, with different inclusion levels, nutritional profiles and feed processing treatments. The inclusion of various levels (1%-30%) of dried whole microalgae biomass in salmon feeding trials showed no adverse effects on growth performance, nutrient digestibility, or utilisation of the feed, although slightly impaired digestibility and improved biological activities were observed depending on size of the fish, species of algae, inclusion rate (Arthrospira, Entomoneis sp., Nanofrustulum sp., Ph.…”

“…Duneliella salina is another promising source of carotenoids as a dietary supplement for fish for both pigmentation purposes as well as health benefits 227 . Other health‐promoting biomolecules from microalgae include beta 1,3‐glucans, such as from Chlorella strains and Euglena gracilis , which can activate the immune system of various fish species 228–230 …”

Immunomodulatory activity of β‐glucans in fish: Relationship between β‐glucan administration parameters and immune response induced

“…Besides that, intraperitoneally injected β‐glucans can stimulate a range of innate immune parameters in fish including leucocytes phagocytic and oxidative burst activities, lysozyme, antiprotease and bactericidal activities in the serum and skin mucus (Chirapongsatonkul et al, 2019; Morales‐Lange et al, 2015; Yamamoto et al, 2020). The intraperitoneally injected β‐glucans can also activate leucocytes to produce more humoural factors such as lysozymes, complements and antibacterial peptides to prevent the invasion and colonization of microorganisms (Misra et al, 2006).…”

“…In comparison with oral and immersion route, the intraperitoneally injected β‐glucans exhibited better immunomodulatory effects in the fish, indicating that the immune response in fish was strongly activated when β‐glucans were delivered intraperitoneally (Sado et al, 2016; Yamamoto, Castillo, & Gatlin, 2020). This may be due to the injected β‐glucans can provide rapid stimulation of immune cells in blood circulation and several organs.…”