Complex immunoenhancer for low salinity prawn as well as preparation method and application for composite immunopotentiator

The invention relates to a composite immunopotentiator for low salinity prawn as well as a preparation method and an application for the composite immunopotentiator The composite immunopotentiator is characterized by comprising the following components by weight percentage: 1-2kg of magnesium sulfate, 1-2kg of bacillus subtilis, 1-2kg of bacillus Licheniformis, 1-2kg of lactic acid bacillus, 1-2kg of mannan oligosaccharide and 2-3kg of fructo-oligosaccharide. The preparation method comprises the steps of: weighing the magnesium sulfate, the bacillus subtilis, the bacillus Licheniformis, the lactic acid bacillus, the mannan oligosaccharide and the fructo-oligosaccharide in proportion, and grinding into fine powder; then mixing uniformly in a mixer, wherein a coefficient of variation in a mixing process in the mixer is smaller than or equal to 5%; and forming the composite immunopotentiator for low salinity prawn. The application of the composite immunopotentiator for the low salinity prawn is that: the composi