Effects of mannan oligosaccharide on the physiological responses, HSP70 gene expression and disease resistance of Allogynogenetic crucian carp (Carassius auratus gibelio) under Aeromonas hydrophila infection

► MOS has the potential to increase immune and anti-oxidative ability of fish. ► MOS has the potential to increase resistance of bacteria pathogen. ► MOS herb has the potential to affect the expression of HSP70 in fish.