Preparation method of additive for improving nonspecific immunity of laying hens

The invention provides a preparation method of an additive for improving nonspecific immunity of laying hens. The preparation method includes the steps: a Newcastle disease La Sota strain is diluted and then is used for inoculating chick embryos, incubation is carried out, and a chicken Newcastle disease vaccine chick embryo allantoic fluid is collected; a formaldehyde solution is added, inactivation is conducted, and the inactivated chicken Newcastle disease vaccine chick embryo allantoic fluid is obtained; and a soybean protein isolate is dissolved in sterile water, sodium alginate, glycerol, okra polysaccharides and the inactivated chicken Newcastle disease vaccine chick embryo allantoic fluid are added, then, a calcium chloride solution is added dropwise, sterile normal saline is usedfor washing, and after pre-freezing and freeze-drying, the additive for improving the nonspecific immunity of the laying hens is obtained. According to the preparation method of the additive for improving the nonspecific immu