Prawns, M. rosenbergii were obtained from a commercial farm in Pingtung, Taiwan, and were shipped to National Pingtung University of Science and Technology (Aquatic Animal Physiology and
Immunology Laboratory), and acclimatised at room temperature (27 ± 1 C) and pH 7.0e7.5 in the laboratory for 2 weeks before experimentation. Only prawns in the intermoult stage were used in
this study. The moult stage was determined under a stereomicroscope according to retraction of the epithelium within the setal base interface of the antennal scale