Tegumental surface alterations of fasciola gigantica (Cobbold, 1885) due to in vitro lead exposure using scanning electron microscopy

Date of Publication


Document Type

Master's Thesis

Degree Name

Master of Science in Biology


College of Science



Thesis Adviser

Mary Jane C. Flores

Defense Panel Chair

Florencia G. Claveria

Defense Panel Member

Divina M. Amalin
Gil A. Cauyan


This study aimed to examine using scanning electron microscope (SEM) the in vitro effects of different lead concentrations in the tegument and observed motility of F. gigantica (giant liver fluke) isolated from livers of carabaos. Percentage relative motility (RM) of flukes after 15 hours lead exposure revealed 100%, 75%, 61% and 30% at 0, 100, 150 and 200ppm respectively. Using these RM values, the lethal concentration (LC50) of lead was 160ppm together with manifestations of physiological stress such as curling and excretion of black exudates. Three types of curling observed were curling of the lateral body margins, at one end of the body and at both ends of the body. SEM studies of the tegument were conducted using the calculated LC50 values (160ppm) including 110ppm and 210ppm as lower concentration and higher concentration, respectively. Results showed that lead exposure of the flukes caused surface alterations in all treatments with different degrees. At 110ppm, sloughing, blebbing, furrowing and folding were observed after 7 and 15 hours post-incubation to lead. However, at higher concentrations (160ppm and 210ppm) wrinkling and crumpling of the tegumental surface were evident. At 7 hours lead exposure, wrinkling was observed and this intensified as crumpling at 15 hours post exposure. In conclusion, liver flukes has a lead tolerance as low as 100ppm and as high as 210ppm which suggests its potential as a possible bioindicator of environmental pollution and promotes its use as a good candidate of an effect indicator based on the distinct surface morphological variations observed in lead-exposed liver flukes.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer optical disc ; 4 3/4 in.

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