Lysozyme activity assay
The lysozyme activity was conducted following previously
described method [34e36]. Briefly, 500 ml of diluted haemolymph
was centrifuged, and the precipitate was mixed with 1 ml (0.02%)
of Micrococcus lysodeikticus (Sigma, USA). The reaction was carried
out at room temperature and the absorbance at 530 nm was
measured after 30 s and 4.5 min. A unit of lysozyme activity was
defined as the amount of sample causing decrease in absorbance
of 0.01 per min