scholarly journals Determination of Some Heavy Metals in Cultured Nile Tilapia (Oreochromis niloticus) in Western Kordofan State, Sudan

Author(s):  
O. A. Idam ◽  
M. Rowaida S. Musa ◽  
Ramy A. Yousif

The current study was conducted in two different localities have been selected in Western Kordofan State (Elsonout and Abu-zabad Localities) to evaluate some heavy metals concentrations (Copper, Cadmium, Zinc, and Lead) in three parts (liver, gills and muscles) of Nile Tilapia (Oreochromis niloticus) cultured in Dams, also to evaluate the same heavy metals concentrations in Dams water where Nile Tilapia is cultured. The evaluation was included the correlation of heavy metals accumulation between fish organs and water samples were compared. Finally, the results were compared with recommended levels by FAO, WHO and other international organizations. A total of 54 samples has been taken from marketable size Nile Tilapia parts (gills; livers and muscles) and subjected to analysis of heavy metals accumulations. Also, a total of 18 water samples were taken from Dams (shallow, middle and deep water). The data was subjected to SPSS using ANOVA. The findings of this work were revealed that, there were a highly significant differences (P≤0.01) in all heavy metals among gills, liver and muscles of Nile Tilapia cultured in Dams. And there was a highly significant difference (P≤0.01) in all heavy metals among gills, liver and muscles of Nile Tilapia according to localities. Anyway, when compared fish organs; we found that, gills were recorded the maximum figures in all heavy metals followed by livers and the minimum figures were recorded by muscles. The results of this study were in the permissible levels recommended by international organizations.

Author(s):  
Ong’eta M. K Wamboka ◽  
Syprine A. Otieno ◽  
Jemimah A. Simbauni

The Nile tilapia, Oreochromis niloticus, is a tropical fish species of commercial importance in both aquaculture and in the wild. It plays a great role in human nutrition and food security. River Ruiru is one of the rivers faced with pollution from nearby industries. It is inhabited by various species of fish such as tilapia and common carp, which, may be harvested by surrounding communities for food. High levels of heavy metals disrupt normal reproductive process in fish. Besides, it has been reported that edible fish contaminated with heavy metals has deleterious effects on the health of humans and other animals that consume them. There is no documented information on the association between heavy metals and the reproductive biology of Oreochromis niloticus in River Ruiru. This study was aimed at assessing the level of heavy metals in fish ovaries and their association with selected reproductive parameters in the reproductive cycle of O. niloticus. Fish samples were collected monthly, for 8 months, from the downstream and upstream sections. Gonadosomatic index (GSI), serum 17β-estradiol (E2) levels and levels of heavy metals lead, cadmium, copper, iron and zinc in ovaries were determined. The levels of the heavy metals were measured using Atomic Absorption Spectrophotometer. The level of E2 was analyzed using Enzyme-Linked Immunosorbent Assay. There was no significant difference in the GSI between the upstream and the downstream sites (t=0.82, p=0.416). Similarly, there was no significant difference in the levels of E2 between the downstream and the upstream sampling sections. In the downstream, the levels of lead and iron in fish ovaries were significantly higher compared to the upstream (lead: t = 3.36, p = 0.002; iron: t = 4.920, p=0.001). The results showed that levels of heavy metals did not associate with the selected reproductive parameters in the Nile tilapia, along River Ruiru. Levels of lead and cadmium were above allowable concentrations for fish consumption when compared to WHO levels. The study recommends that the Ministry of Environment and Natural Resources should put measures in place to stop discharging raw effluents into River Ruiru.


2012 ◽  
Vol 64 (1) ◽  
pp. 192-197 ◽  
Author(s):  
R.M.R. Sousa ◽  
C.A. Agostinho ◽  
F.A. Oliveira ◽  
D. Argentim ◽  
P.K. Novelli ◽  
...  

The performance of Nile tilapia (Oreochromis niloticus) raised in cages furnished with an automatic dispenser, supplied at different frequencies (once per hour and once every two hours) and periods (daytime, nighttime and both) was evaluated. Eighteen 1.0m³ cages were placed into a 2000m² pond, two meters deep with a 5% water exchange. One hundred and seventy tilapias, with initial weight of 16.0±4.9g, were dispersed into each 1m³ cage and the feed ration was adjusted every 21 days with biometry. Data was collected from March to July (autumn and winter). Significant difference to final weight (P<0.05) among treatments was observed. The increase in feeding frequency improves the productive performance of Nile tilapias in cages and permitted better management of the food. The better feed conversion rate for high feeding frequency (24 times day-1) can result in saving up to 360kg of food for each ton of fish produced, increasing the economic sustenance for tilapia culture and suggesting less environmental pollution.


2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Nahid A.A. Siddig ◽  
Asma A. Ahmed ◽  
Sarra A.M. Saad ◽  
Faisal Hammad Mekky Koua

Municipal sewage sludge from wastewater treatment is an important nutritional source for sustainable agriculture. Here, we report on the assessment of the accumulation of heavy metals in Nile tilapia Oreochromis niloticus (Trewavas 1983) fed on earthworms Eisenia fetida reared on soil treated with different concentrations of sewage sludge (25% and 100%) during sludge-earthworm-fish short-term cycling. In this short-term cycling the Nile tilapia collected from the White Nile were chosen as final consumers, whereas the earthworms reared on loam soil mixed with different ratios of sludge were used as a feed for the final consumers. Our results indicate that the concentrations of Cd2+, Cr2+, Pb2+ and Zn2+ in the sludge treated soil are proportional to the sludge content in the soil. Importantly, the accumulation of these heavy metals was significantly low in the earthworms and the Nile tilapia in comparison with the treated soil and that these concentrations in the Nile tilapia were below the international limits recommended by the US Environmental Protection Agency (2014). Moreover, the growth and overall flesh quality of the fish were improved as indicated by the growth increase up to 146% when fed on earthworm reared in 100% sludge. Additionally, our physicochemical properties (i.e. pH, soil moisture, electric conductivity and organic matters) evaluation on the soil indicates an improvement of the soil quality when mixed with sewage sludge. These results suggest a sustainable application of sewage sludge in fish culture owing to its high nutritional values, low cost, and low risk of hazardous heavy metals when using primary consumers with heavy metals bioaccumulation capability such as E. fetida.


2017 ◽  
Vol 22 (1) ◽  
pp. 10-16
Author(s):  
Suraj Babu Ghimire ◽  
Rahul Ranjan

 This study was done to explore the effect of replacing mustard oilcake by linseed oilcake in feed on the growth performance of Nile Tilapia (Oreochromis niloticus). Mustard oilcake (MOC) was replaced by linseed oil cake (LOC) at three different level 0%, 50% and 100% to prepare three different types of diets. Diets were prepared with about 18% analyzed crude protein content. Fingerlings were kept in three happa with three replications for each diet in completely randomized design (CRD). Fish of average weight 5.31 g were stocked in happa having size 1.5m×1.5m×1.2m. The experimental fish were fed 3% of their body weight per day, once in the morning for five months continuously. No significant difference (p>0.05) in final mean weight, final total weight, average daily weight gain (DWG), survival rate, extrapolated gross fish yield (GFY), extrapolated net fish yield (NFY) and apparent feed conversion ratio (AFCR) among different treatments were observed. Hence, linseed oilcake can be used as the substitute in the feed of tilapia, if it is locally available.  Journal of Institute of Science and Technology, 2017, 22 (1): 10-16 


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