The effect of β‐1,3‐glucan derived from Euglena gracilis (Algamune^™) on the innate immunological responses of Nile tilapia (Oreochromis niloticus L.)

Abstract

Algamune is a commercial additive produced from Euglena gracilis, providing a rich source of the β-1,3-glucan paramylon. Isolated kidney phagocytes of Nile tilapia were incubated with graded doses (0, 8, 16, 32, 64 and 128 μg/ml) of Algamune and purified paramylon to gauge their ability to elicit the production of reactive oxygen species. A linear response was observed for extracellular superoxide anion for both sources but only Algamune for intracellular superoxide anion. After corroborating the immunostimulant properties ex vivo, a feeding trial was conducted to evaluate the dietary supplementation of Algamune (0, 100, 200, 400 and 800 mg/kg of diet) for Nile tilapia. Fish were fed for 3 weeks, after which, fish were sampled for blood and head kidney phagocytes. The remaining fish were challenged with Streptococcus iniae. Macrophage extracellular superoxide anion production was significantly elevated in fish fed diets with 200 mg of Algamune kg when compared to fish fed the basal diet. Even though the disease challenge did not show statistical differences, it is worth mentioning that fish fed intermediate doses of Algamune had lowest numerical mortality values. Therefore, Algamune was demonstrated to enhance some immunological responses of tilapia both in ex vivo and in vivo.

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

“…No differences were observed for production performance and nutritional composition of whole‐body tissues, regardless of the nature of the BGs and levels. This result is in agreement with previous studies which evaluated Euglena gracilis as a dietary source of paramylon as a short‐term feed additive for teleost fish (Yamamoto, Sutili, Hume, & Gatlin III, ; Yamamoto, Yin, Rossi, Hume, & Gatlin, ), but not with Saccharomyces ‐derived BG, where some prolonged exposure to the dietary supplement promoted better growth performance of other fish species (Aramli, Kamangar, & Nazari, ; Do Huu, Sang, & Thuy, ; Ji et al, ; Kühlwein, Merrifield, Rawling, Foey, & Davies, ; Pilarski, de Oliveira, de Souza, & Zanuzzo, ). However, it is unclear if these growth‐promoting properties found in those studies were being induced by the BG per se, or if other components of the Saccharomyces cerevisiae commercial products, (e.g., nucleotides, mannans, oligosaccharides) were playing role.…”

“…However, at the end of the 8th week of feeding, a reduced P value (0.15) could be observed with higher values for the highest inclusion levels of BGs and 50 mg/kg of zymosan. Similar trends also were observed by Li, Wen, and Gatlin () and Yamamoto, Sutili, et al () for HSB and red drum, respectively, where reduced P values were obtained but no statistical differences were detected, with the intermediate doses of dietary BG presenting higher activity values when compared to those fed the basal diet. In addition, two separate studies feeding rainbow trout diets supplemented with BG from Saccharomyces also presented numerically higher lysozyme activity but with no statistical differences (Douxfils et al, ; Lauridsen & Buchmann, ).…”

Immune Status and Hepatic Antioxidant Capacity of Gilthead Seabream Sparus aurata Juveniles Fed Yeast and Microalga Derived β-glucans

“…Accordingly, a study done in gilthead seabream fed a 0.1% supplemented feed with a macroalgae derived BG (laminarin) did not show changes in serum antiprotease activity and IgM levels after 4 weeks of feeding [23]. Yamamoto et al [50] tested different levels, ranging from 0% to 0.8%, of microalgae (Euglena gracilis)-derived BGs in Nile tilapia both in vitro and in vivo. While exposing naïve head-kidney phagocytes directly to BGs facilitated the activation of immune cells increasing bactericidal activity against Streptococcus iniae and superoxide anion production, in vivo immune effects were found to be more moderate.…”

Bioproducts From Euglena gracilis: Synthesis and Applications

“…Until now, the research on the health benefits of paramylon has focussed mainly on applications to treat human conditions, but it has been suggested that it also could be beneficial to livestock and fish health. Studies undertaken with porcine leucocytes, chickens (broilers) and fishes (e.g., rainbow trout, Nile tilapia, and red drum) have shown that supplementation of the medium with paramylon or inclusion of paramylon in a diet resulted in immunostimulatory and/or -regulatory activity on the cells or animals, with positive effects such as host protection against parasites (Sonck et al, 2010; Skov et al, 2012; Levine et al, 2018; Yamamoto et al, 2018a,b). However, more studies would be needed to elucidate the nature of the observed effects and to confirm quantifiable benefits for the animals.…”