Histological Analysis Of Gill And Liver Of Nile Tilapia (Oreochromis niloticus Linnaeus, 1758) In The Batang Arau River, Padang City

Abstract

The Batang Arau River is one of the main rivers in Padang City which is used intensively for various domestic, industrial and transportation activities, so it has the potential to experience a decline in water quality. Water pollution can have a direct impact on aquatic organisms, especially fish, which can be demonstrated through changes in vital organ tissue. Gills and liver are organs that are sensitive to environmental changes. This study aims to determine the histological profile of the gills and liver of tilapia (Oreochromis niloticus) that live in the Batang Arau River. This research uses descriptive methods with qualitative and quantitative approaches. Tilapia fish samples were taken from three different locations on the Batang Arau River, namely agricultural areas (T1), rubber factory industrial areas (T2), and densely populated areas (T3). Gills and liver were prepared using the paraffin method with Hematoxylin Eosin (HE) staining. Histological observations were carried out using a light microscope, then the level of tissue damage was analyzed using a scoring method based on the percentage of cell damage. The water quality parameters measured are temperature and pH. The results showed that there were histological changes in the gills in the form of primary lamella hyperplasia, secondary lamella distortion, lamella fusion, edema, epithelial lifting, congestion and necrosis, as well as in the liver in the form of sinusoid dilatation, congestion, vacuole degradation, sinusoid congestion, karyorrhexis and karyolysis. The highest level of histological damage was found at the T3 location, while lower damage was found at T1 and T2. Keywords: Histology, gills, liver, Nile tilapia (Oreochromis niloticus), Batang Arau River.