Evaluation of different microalgae species and Artemia (Artemia franciscana) as possible vectors of necrotizing hepatopancreatitis bacteria

Microalgae species commonly used in shrimp aquaculture and observed in shrimp habitat (Chaetoceros muelleri, Dunaliella sp. and Navicula sp.), and Artemia (Artemia franciscana) were evaluated as possible vectors of necrotizing hepatopancreatitis bacteria (NHPB). Microalgae species and Artemia were exposed to NHPB. Eight days after inoculation, NHPB were detected (by PCR) only in Navicula sp. Thereafter, the three inoculated microalgae were used to feed white shrimp (Litopenaeus vannamei): shrimp fed on C. muelleri and Dunaliella sp. resulted negative to NHPB after 12 days, whereas 20% of shrimp fed on Navicula sp. were to NHPB positive. Regarding to Artemia, NHPB were detected in the organisms (dead or alive), four and eight days post inoculation. Microalgae and Artemia controls remained negative for NHPB during the experimental period. The results suggest that planktonic microalgae (C. muelleri and Dunaliella sp.) cannot be vectors of NHPB, while there is a possibility that benthic microalgae (Navicula sp.) and Artemia sp. can act as vectors of the bacteria.