Innate immune responses and efficacy of using mushroom beta-glucan mixture (MBG) on orange-spotted grouper, Epinephelus coioides, aquaculture

• Application of mushroom beta-glucan compound to increase immune responses in fish.
• The use of mushroom beta-glucan compound (Ganoderma lucidum and Coriolus versicolor) as immunostimulant.
• The mechanism of extracts preparation and supplementation of diets.
• Measurement the innate immune responses of organ-spotted grouper (Epinephelus coioides).
• The mushroom beta-glucan compound used in the actual field of culturing orange-spotted grouper groupers.

This study attempts to describe the effects of innate immunity responses and field application of mushroom beta-glucan mixture (MBG) in cultured orange-sported grouper, Epinephelus coioides. Chemical analysis for MBG showed that the mixture contains 34.06% of macro-molecular polymers with bio-active linkage such as 3-; 3,4- and 4,6-glucopyranosyl and 6-linked galactopyranosyl residues.Study performed on the innate immunity showed that oral ingestion of MBG at 1.0 g and 2.0 g per kilogram of feed levels may significantly enhance the lysozyme activity, alternative complement activity, phagocytic activity and respiration burst of the experimental groupers.Observation on the experimental challenge of pathogen showed that uses of MBG at 0.1% and 0.2% levels in feed might significantly enhance the protection of grouper against Vibrio alginolyticus.Field trials performed on short and long-term culture showed that feeding of diet containing 0.1% or 0.2% of MBG may significantly enhance the survival of cultured groupers up to 16% when compared with those obtained from controls.