Glucan-MOS ® improved growth and innate immunity in pacu stressed and experimentally infected with Aeromonas hydrophila

Abstract

We tested the efficacy of a commercial product (Glucan-MOS) derived from yeast Saccharomyces cerevisiae, containing two combined products, β-1,3-1,6 glucans and mannans on the growth, feed efficiency, stress and innate immune responses of juvenile pacu (Piaractus mesopotamicus) after a stressful handling and bacterial inoculation. For this, we evaluated the serum cortisol and plasma glucose levels, the respiratory activity of leukocytes, the serum lysozyme levels, as well as the number of circulating erythrocytes and leukocytes of fish fed during 30 days with diets containing increased levels of Glucan-MOS (0.0, 0.1, 0.2, 0.4 and 0.8%). The supplementation of 0.1% improved weight gain, feed conversion and the protein efficiency ratio compared to a control diet. The 0.2 and 0.4% Glucan-MOS diets were sufficient to increase the respiratory burst of leukocytes and lysozyme activity, the number of thrombocytes, neutrophils and monocytes in the blood after a stressful handling and bacterial challenge, and minimized stress response as shown by decreased cortisol and glucose levels when compared to the control. The results of this work reinforce the benefits of the adoption of feeding strategies including combination of both β-1,3-1,6 glucans and mannans as a dietary supplement in periods prior to intensive management. The 30-day period was sufficient to stimulate growth performance, improve nutrient utilization, minimize stress response and modulate innate immunity responses.

Growth, physiological and immune responses of Arapaima gigas (Arapaimidae) to Aeromonas hydrophila challenge and handling stress following feeding with immunostimulant supplemented diets

“…Similarly, in P. mesopotamicus has been demonstrated that supplementation with 0.1 or 1.0% β-glucan, respiratory burst of leukocytes, complement hemolytic activity, lysozyme activity and number of leukocytes increased after challenge with A. hydrophila, reducing fish mortality [25]. The addition of 0.2 and 0.4% of Glucan-MOS ® was also sufficient to positively influence these immune parameters in P. mesopotamicus after challenge of stress and infection with A. hydrophila [10]. In E. coioides supplemented with different concentrations of S. cerevisiae and challenged with inoculation of Streptococcus sp.…”

“…The previous studies indicated that S. cerevisiae-based products were efficient in promoting fish growth and potentially viable for aquaculture use from the production viewpoint. Physiological indicators of health [6,16] and immune status [2,6,10] are often used to evaluate the efficacy of dietary supplementation of feed additives. In the current study, VSI and HSI of A. gigas fed with different Aquate Fish™ ® levels were not altered, although plasma triglycerides, cholesterol and glucose increased in fish fed 12 g Aquate Fish™ ® .…”

“…However, with the development of global aquaculture, several problems have arisen, including the deterioration of water quality, parasitic and bacterial diseases [1,3,4,7]. Diets supplemented with immunostimulants based on Saccharomyces cerevisiae, which contain beta-glucan polysaccharide, mannanoligosaccharides and chitin have been recommended for improvement in fish production [7][8][9][10]. Diets supplemented with immunostimulants may improve fish performance by establishing the intestinal microbiota and better preparing fish immune system.…”

“…Diets supplemented with immunostimulants may improve fish performance by establishing the intestinal microbiota and better preparing fish immune system. As a consequence, fish are more resistant to stress, including parasitic and infectious diseases [6][7][8][9][10]. Aquate Fish™ ® is a commercial feed additive that may play a role in the fish defense systems.…”

Dietary Mannan-Oligosaccharide Increases Reactive Oxigen Species Production but Decreases Serum Lysozyme in High Levels of Inclusion for Nile Tilapia

“…Moreover, the mannose present in MOS particles can be recognized by the innate immune system through the mannose binding lectin (MBL), immunomodulating several immune responses (Torrecillas et al, 2014). Dietary use of MOS has been reported enhancing innate immune parameters in fish, such as white blood cell numbers, phagocytosis, lysozyme and reactive oxygen species (ROS) (Song et al, 2014), and also increasing growth and survival in Dicentrarchus labrax (Torrecillas et al, 2007;, Oncorhynchus mykiss (Staykov et al, 2007), Labeo rohita (Andrews et al, 2009) and Piaractus mesopotamicus (Soares et al, 2018). However, according to the consulted literature, the level of inclusion of MOS in fish diets vary due to the species and few are the studies presenting substantial results in health of Nile tilapia (Sado et al, 2008;Selim and Reda, 2015;Levy-Pereira et al, 2018).…”