Evaluation of Water Quality on TNF- α and IL- 1 Immune Genes in Oreochromis Niloticus Fish at El Manzala Lake in Egypt

Abstract

Lake Manzala is known to be from the most significant sources of inexpensive different fish species for human consumption in Egypt. The Lake receives pollution from various sources; domestic wastewater, industrial wastewater, and agricultural drainage directly without any treatments, which lead to many environmental disorders. The following research was conducted for lake water quality evaluation and how it impacts the expression of Tumor necrosis factor- α (TNF- α) and Interleukin-1 (IL- 1) immune genes. Sampling was done seasonally from October 2015 to September 2016, where water and fish samples were collected from 4 locations in El Manzala Lake after mixing with Bahr El Baqr drain (sampling points were 4 km apart from each other). Average values of dissolved oxygen, chemical oxygen, and biological oxygen demand were 6.7 mg O2/l, 139.4 mg O2/l, 92.8 mg O2/l, respectively. For the Nitrogen group, the average concentration of ammonia, nitrite, and nitrate was 0.7 mg/l, 0.38 mg/l, and 0.38 mg/l, respectively. The average records of total bacterial count and total and fecal coliform suggesting high loads of contaminants, particularly in sampling sites close to Bahr El Baqr drain. The relative occurrence of cyanobacteria in water samples was influenced by increasing lake water temperature. The expression of the immune genes for TNF- α and IL- 1 in Nile Tilapia fish liver was confirmed by RT-PCR. The results showed up-regulation of these genes in the liver of Nile Tilapia fish, especially in warm seasons (summer, late summer). TNF-α and IL- 1 level in Nile Tilapia fish could be used as early diagnostic indicators to different environmental events and also are helpful and reliable bioindicators in estimating pollutants of the aquatic environment. High levels of pollution in El Manzala Lake were recorded in this study that may proceed with health risks to a human. Therefore, the Lake needs proper policies to protect and preserve its ecological integrity and biodiversity.