Crustacean hemolymph microbiota: Endemic, tightly controlled, and utilization expectable.

Increasing number of evidence suggests that the hemolymph of numerous apparently healthy invertebrates is unsterile. Investigation of hemolymph microbiota properties and the homeostasis between host and bacteria is helpful to reveal bacteria pathogenesis, host immunity, and possible utilization in disease control. Crustaceans represent a large family of aquatic animals. Therefore, crustacean fishery is of important economic value worldwide. Research related to crustacean hemolymph microbiota has been performed over the years. In the present study, we conclude currently available information and present a comprehensive analysis regarding homeostasis between host and bacteria. In general, the presence of microbiota in crustacean hemolymph is an endemic event and can be influenced by internal and external factors. Opportunistic bacteria may have generated some changes or mutations under hemolymph stress. Meanwhile, hosts suppress hemolymph microbiota proliferation with the help of some critical antimicrobial peptides and lectins. The hemolymph microbiota may be beneficial for hosts as resistance against external damages. In addition, the hemolymph microbiota may be utilized in aquaculture.