Molecular Identification And Phylogenetic Analysis Of Anisakidae Larvae From The Marine Fishes Of Perciformes In The South China Sea

In the present study, the survey of anisakid nematodes (Nematoda: Anisakidae) from marine fishes of Perciformes in the South China Sea were made using morphological and molecular method.2396larvae of anisakid nematodes were collected from the410fishes (representing78species). The preliminary classification of the collected larvae were made based on the morphological characters. Subsequently, the internal transcribed spacer (ITS region) of rDNA of representative samples selected from each type of larvae were applified using conservative primer. Each PCR product was cleaved by restriction enzyme TaqI and RsaI.PCR-RFLP combined with sequences analysis revealed the larvae nematodes at least represent six species from the South China Sea (except Anisakis), there are Raphidascaris lophii, Hysterothylacium longilabrum, H zhoushanensis, H amoyense, H aduncum and Hysterothylacium sp. NH-2012. In the South China Sea, Hysterothylacium sp.NH-2012and R. lophii are the dominant species of the faminly Anisakidae.1280out of2396Anisakidae larvae are Hysterothylacium sp.NH-2012and914are Raphidascaris lophii, accounting for53%and38%of the total, respectively. The hosts including78fish species such as Namipterus japonicus、Decapterus maruadsi、Thunnus alalunga、Trichiurus haumela、 Chaetodontidae butterflyfish、Epinephelus amblycephalus、Dentex tumifrons、Centroberyx lineatus、Trachurus japonicus and so on. The morphological characters, ITS sequences and infective status of6species in the South China Sea were reportedIn this study, Maximun-Likelihood(ML) tree and Maximun-Parsimony (MP) tree were constructed based on the ITS sequences from the present study and Genbank using MEGA5.0(Molecular Evolutionary Genetics Analysis.5.0version) software, Anisakis simplex was selected as outgroup. The results showed the MP and ML trees were divided into two groups, one group including the species of Hysterothylacium, the other including the species of Raphidascaris In the Hysterothylacium group, Ea3and Hysterothylacium fabri was relatively close, but didn’t clustered into a branch. Sal always clustered with Hysterothylacium aduncum; Pj1always clustered with Hysterothylacium longilabrum Pe52always clustered with Hysterothylaciumamoyense, and Dm23、A145always clustered with Hysterothylacium zhoushanensis. In the group, Ta2and Raphidascaris lophii always clustered together. The phylogenetic analysis proved that these nematodes classification status once again.This paper, molecular identification and system development of the South China Sea perciformes fish parasitic nematode larvae were detailed studied for the first time, and also reported the infection rates and infection intensity, provided the reference for fish nematode disease prevention.