Ecological and biological studies on the Nile tilapia Oreochromis niloticus along different sites of lake Burullus

Abstract

ABSTRACTake Burullus represents an economically important lake in Egypt , due to its rich fishery resources. Unfortunately, the lake is exposed to many kinds of chemical and biological pollutants in addition to the remains of agricultural and wastes that are disposed into it. So, the aim of the present study was compare the quality of water samples collected from three different sites along lake Burullus; a site of the lake in contact with the Mediterranean sea called ElBoughaz inlet, western sector of the lake where agricultural drainage discharged and eastern sector where agricultural and industrial effluents.Water quality of samples collected from the different studied sites along the lake showed highly significant (P< 0.01) differences with the highest values in the dissolved oxygen content and salinity at El-Boughaz inlet. However, water samples collected from the eastern and western sectors of the lake showed highly significant (P< 0.01) increase in ammonia, nitrite, Cu, Zn and Mn but insignificant (P> 0.05) Pb concentration. Bioaccumulation of either of the studied heavy metals in gills, liver, kidneys and muscles of the Nile tilapia; Oreochromis niloticus collected from the eastern and western sectors of the lake was much higher than that of fish collected from El-Boughaz inlet. Moreover, histopathological sections showed clear damage of gills, liver and kidney of fish collected from eastern and western sectors of the lake.Furthermore, Oreochromis niloticus collected from eastern and western sectors of the lake had lower condition factor values, hepatosomatic index, RBCs, Hb, Ht, serum total protein and total lipids but higher liver water contents, WBCs, MCV, MCH, serum glucose, AST, ALT, creatinine and uric acid.The obtained results also revealed that the meat quality of the collected fish from El-Boughaz inlet was more superior than those of fish collected from the eastern and western sectors of the lake.

Biochemical and histological assessment of some heavy metals on Biomphalaria alexandrina snails and Oreochromis niloticus fish in Lake Burullus, Egypt.

“…The histopathological changes observed in the liver of O. niloticus are similar to that recorded by Zaghloul et al (2007) and Abdel-Aziz et al (2011), which confirmed the present study biochemical change in the liver enzymes; AST and ALP and in agreement with Ajani and Akpoilih (2010) who found that the liver tissue necrosis was associated with the elevation of the activates of ALT and AST. The kidney is a major organ involved in fluid and ionic balance of fish.…”

“…The present kidney pathological alterations included vacuolization, dilation in renal cells, necrosis, glomerular shrinkage and vacuolar degeneration in the epithelium of renal tubules and separation from the basement membrane resulting from edema. These symptoms are similar with that observed by Zaghloul (2000) and Zaghloul et al (2007) and similar to those found in Mugil sp. and C. carpio that exposed to lindane (Ortiz et al, 2003); O. mykiss infected with Micrococcus luteus (Aydin et al, 2005) O. niloticus exposed to ammonia (Benli et al, 2008); Dicentrarchus labrax exposed to mercury (Giari et al, 2007) and O. niloticus exposed to Cu and Pb (Osman et al, 2009).…”

“…This increase may be attributed to the changes in hepatic protein synthesis (Saad et al, 1984) and Mahmoud et al, 2002) or due to the stress of the polluted habitat. The increase in the serum total protein level was also reported by ElNaggar et al (1998) for O. niloticus collected from a polluted area along the River Nile at the industrial zone of Helwan and by Zaghloul et al (2000) for Nile tilapia collected from fish ponds irrigated by agricultural drainage water. In addition, increased values of protein and albumin in fish blood was reported by Authman et al (2013) in Clarias gariepinus collected from El-Rahawy drain and by El-Khayat et al (2016) in fish samples collected from Lake Manzala.…”

“…Among the studied sites in Lake Burullus, Khashaa and Shakhloba sites showed the least values of DO this may be attributed to these sites are near to the discharge points of drains station 7 & station 8, respectively, while ElBughaz Intel site showed the highest DO value suggesting the dilution role of seawater in the improvement of lake water quality in this site. These findings are in consequence with that of Zaghloul et al (2007) who recorded higher value of DO content at El-Boughaz inlet than that observed in eastern and western sectors, the much suffered from the industrial and agricultural discharge causing high levels of organic, inorganic salts and heavy metals that lead to fish hypoxia. The present pH values were slightly lie on alkaline side, this is may be related to the photosynthetic activity of phytoplankton and other aquatic plants, (Emara et al, 2016, Tayel et al, 2014and Gohera et al, 2017.…”

“…Lake Burullus has received a great attention because of its economic importance for being a significant source of fish production in Egypt. The lake water quality is affected by discharge of seven agricultural drains containing agricultural, industrial, and domestic wastewaters without any pre-treatment, (Zaghloul et al, 2007;Nafea and Zyad, 2015;Emara et al, 2016 andEl-Batrawy et al, 2018). Several authors studied O. niloticus fish and B. alexandrina snails as bio-indicators for water pollution (Abd El-Aziz et al, 2011;Abdel-Moneim et al, 2012;El-Khayat et al, 2015aand El-Batrawy et al, 2018.…”