Occurrence of neoechinorhynchus sp. (Acanthocephala: Neoechinorhynchidae) in cultured tilapia, [Oreochromis niloticus (L.), perciformes: Ciclidae] from sampaloc lake, Philippines

Abstract

Cultured tilapias (Oreochromis niloticus L.)were sampled from Sampaloc Lake, Philippines with 42% (38 out of 90) found infected with mature forms of acanthocephalan parasite in the intestine. Results showed that season had a significant influence on the proportion of infected fish (c2 = 19.15, p<0.05) with the prevalence being higher during dry season with 58% (35 out of 60) compared to rainy season with 10% (3 out of 30).This finding suggests the seasonal occurrence of mature acanthocephalan worm in O. niloticus. However, there was no significant difference in the mean intensity between dry (4.31±3.68) and rainy (4.00±2.00) seasons. Infection intensity had a significant positive correlation with length and weight (r = 0.63 and 0.65, respectively, p<0.05) of infected fish. However, there was no significant association between infection intensity and fish condition index. Scanning electron microscopy revealed the number and arrangement of proboscis hooks; hence, classifying the acanthocephalan specimens as belonging to genus Neoechinorhynchus. Specimens were distinguishable with short, globular proboscis armed with 18 hooks radially arranged in 3 circles with 6 hooks each. The anterior hooks with mean length of 36.54±4.61 μm and the middle and posterior shorter hooks (10.95±1.87 μm) were the most reliable basis for identification to genus level. ©Rushing Water Publishers Ltd. 2012.

Source or Periodical Title

Asia Life Sciences

ISSN

1173375

Page

287-298

Document Type

Article

Subject

Acanthocephala, Cultured tilapia, Endoparasite, Infection intensity, Neoechinorhynchus, Oreochromis niloticus, Philippines, Sampaloc lake

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