Preparation method and application of marine prebiotic galactofucosan

The invention discloses a preparation method and application of marine prebiotic galactofucosan. The preparation method of the galactofucosan comprises the following steps: (1) decolorizing with ethanol; (2) extraction of polysaccharide by an enzymolysis method: the mass ratio of cellulase to pectinase to trypsin is 2: 2: 1, the pH is maintained at 5.71, extraction is performed at 52 DEG C for 35 min, a crude polysaccharide solution is centrifugally concentrated, and crude sargassum thunbergii polysaccharide is obtained after dialysis and drying; and (3) separating and purifying the sargassum thunbergii crude polysaccharide. A formula of the dog and cat intestinal tract health food comprises the following raw materials in parts by mass: 70 to 90 parts of chicken thigh meat, 0.2 to 0.8 part of galactofucosan, 0.5 to 1 part of fructo-oligosaccharide, 0.1 to 0.5 part of mannan oligosaccharide, 1 to 3 parts of a saccharomyces cerevisiae extract, 0.01 to 0.05 part of sodium butyrate, 0.5 to 1 part of lysozyme, 0.1