Prevalence, molecular characterization and the effects of boyprid isopod Probopyrus buitendijki infestation on the Macrobrachium rosenbergii from Nyatoh River, Terengganu, Malaysia

Bopyrid isopod, Probopyrus sp., is an ectoparasite of the freshwater prawn, Macrobrachium spp. The prevalence, morphology, and molecular identity of the parasite collected from Macrobrachium rosenbergii in Nyatoh River, Terengganu, Malaysia were reported herein. Also, the physiological and histological effects of the parasite on the infected prawn were evaluated. A total of 102 M. rosenbergii were collected using both passive and active gears. Out of which thirty-nine samples of the M. rosenbergii, (38.24%) were parasitized by the Probopyrus sp., evident by the visible bulges observed in the prawn’s branchiostegite. Female prawns were observed to have a higher infestation (p < 0.05) than males, while parasitism seemed to be significantly higher (p < 0.05) in middle-sized prawns compared to larger samples. The collected specimen was morphologically suspected to be Probopyrus buitendijki (characterised by a subcordate body that is slightly distorted with five oostegites and black pigment) and was genetically confirmed using 18 S rDNA sequencing. The infested prawn showed a significant reduction (p < 0.05) in hemocyte count and hyaline cells. Significant tissue alterations in the gills and hepatopancreas of the infested prawns were also observed when compared to the control. The various histopathological changes recorded in the infested gills include epithelium lamellae lifting, mild necrosis, hyperplasia of the epithelial cells, pillar cell disruption, and epithelium rupture with haemorrhage. Also, a significant vacuolation of B cells was observed in the infested hepatopancreas compared to the non-infested prawns. It was therefore concluded that the P. buitendijki infestation may strongly correlate with the size and sex of the host and have a significant physiological and histopathological effect on the infested prawns.