Prepared shrimp mucus (100 μL) was added into the wells of a 96- well micro-titre plate and incubated overnight at 4 °C. Then, the wells were washed three times with sterile PBS to remove the nonimmobilized mucus. Subsequently, the labelled bacteria (100 μL) were added to the immobilized mucus and incubated at 37 °C for 1 h.Wells were washed five times with sterile PBS and treated with 0.05% trypsin (100 μL) for 10 min at room temperature to liberate the bacteria. Cold, sterile brain–heart infusion (100 μL) was added to quench the trypsin activity, and samples were collected to measure the fluorescence with a fluorescence spectrophotometer (Hitachi F-4500, Japan) with an excitation wavelength of 500 nm and width of slit of 2.5 nm. The adhesive rate is presented by the ratio of the fluorescence of adherent bacteria
to initial bacteria.