Abstract:
The study was conducted to compare the current water pollution in Laguna Lake and Taal Lake (Philippines) through the analysis of histopathological changes/lesions in the gills and liver of Chanos chanos. A total of 60 specimens of 3-month old Chanos chanos were taken separately from three selected sampling stations along the Laguna Lake (Taguig, Rizal, and Laguna) and along the Taal Lake (Subic Haya, Bilibinwang and Mamalao). Liver and gills were excised and prepared for light microscopy. The gills of Chanos chanos from Taal Lake and Laguna Lake showed significant histopathological changes/lesions which include macrophage infiltration, lamellar sinus dilation, lamellar sinus constriction, mucus cell proliferation, increased mucus secretion, chloride cell proliferation, lamellar fusion, vascular congestion, hyperplasia, hypertrophy, epithelial lifting, and clavate lamellae. For liver histopathology, the following responses were observed: lymphocyte infiltration, macrophage accumulation, necrosis, vacuolar degeneration, atrophy, congestion, bile stagnation, fatty degeneration and cloudy swelling. Such manifestations indicate disturbances of certain physiological aspects in Chanos chanos. Gill lesions were observed in all 60 samples. Liver lesions were observed more frequently in samples from Laguna Lake. Furthermore, semiquantitative analysis of histopathological lesions in both gills and liver showed greater severity in samples obtained from Laguna Lake. The present study has demonstrated the suitability of histopathological biomarkers in fish for assessing water pollution in lake ecosystems.
