Effect of environmental parameters on immune response of the Indian spiny lobster, Panulirus homarus (Linnaeus, 1758)

Abstract

he high export value of the Indian spiny lobster Panulirus homarus increasingly attracts the aquaculturists for farming and fattening. However, lack of knowledge on the effect of environmental parameters on the immune system of this animal could result in high mortality, which ultimately may cause major loss to the industry. Here, we report the effect of salinity (20, 25, 35, 40, and 45‰), pH (5.0, 8.0, and 9.5), dissolved oxygen (DO) (1 and 5 mg L−1), and ammonia-N concentration (0, 0.5, 1.5 and 3 mg L−1) on the immune response of P. homarus measured in the haemolymph in terms of Total Haemocyte Count (THC), phenoloxidase (PO) activity, and NBT-reduction. Our data showed significant reduction (P < 0.05) in THC, and NBT-reduction at lower (20‰) and higher (45‰) salinities. However, PO activity showed significant disparity, showing an increasing trend from 20 to 45‰. Significant reduction (P < 0.05) in THC and PO activity under acidic and alkaline conditions, under hypoxic condition (1 mg L−1), and at the higher ammonia-N concentrations than their respective optimal conditions were observed. Thus, suggesting that extreme environmental parameters can induce modifications in the immune system of the spiny lobster P. homarus, which may enhance their susceptibility to opportunistic pathogens. The humoral parameters such as THC, PO activity, and NBT-reduction can be used as potential stress indicators for healthy management of spiny lobsters.