Antibacterial activity in the haemolymph of western rock lobster,Panulirus cygnus

Abstract

Nonspecific antibacterial activity (ABA) of lobster haemolymph was investigated as an indicator of lobster immune-system status and health condition. To determine whether ABA was localised in the plasma or in the haemocytes, we destroyed the haemocyte membrane by sonication and analysed samples containing plasma and haemocyte lysates for ABA along with sera from the same lobsters. Haemocytes were the main site of ABA in lobster haemolymph. In an experiment designed to assess typical handling conditions, lobsters were placed for 6 h under treatment conditions simulating five transport/storage approaches: submerged in flow-through water, sprayed with flow-through water, submerged in recirculating water, sprayed with recirculating water, and exposed to humid air. The lowest ABA was observed in the two submerged treatments and the highest in the two spray treatments. Lobsters that subsequently survived a simulated live-shipment procedure exhibited significantly lower ABA than did those found dead or weak during a subsequent 7 days of holding in the tank. We concluded that handling stress is associated with high ABA level in lobster haemolymph.