The lysosome and lysozyme response in Chinese shrimp Fenneropenaeus chinensis to Vibrio anguillarum and laminarin stimulation

The effect of laminarin and Vibrio anguillarum on neutral red retention (NRR) time of lysosome and lysozyme activity in blood cells was investigated in Chinese shrimp, Fenneropenaeus chinensis. In addition, the variation of total haemocyte counts (THC) and differential haemocyte counts (DHC) were dtermined simultaneously. The results showed that the lysosome membrane stability was significantly elongated with the longest NRR time for 180 min at 3 h after lamianrin injection, (p < 0.05). The lysozyme activity of haemocytes showed a moderate increase simultaneously. THC also increased and with a highest percentage of semi-granular cell counts at 3 h after laminarin injection. However, the NRR time sharply decreased with the shortest NRR time for 13 min at 1.5 h after V. anguillarum injection. Compared to the control group, the lysozyme activity obviously increased after injection, which was demonstrated at 1.5 h though the THC decreased. The percentage of hyaline cells increased obviously after V. anguillarum injection (p < 0.05). The results suggested that the shrimp immune status could be evaluated by using lysosome membrane stability and lysozyme activity.