Is the consumption of Tilapia zillii and Clarias gariepinus from Edku Lake — El Beheira Governorate —Egypt safe for humans: a physiological and biochemical study and determination of five trace elements

Abstract The Egyptian government seeks to develop the northern lakes, including Edku Lake in the El Beheira governorate, to enhance the physiological functions of fish, and thus, improve their quality and promote their products. Therefore, this study was performed on the two cheapest fish species T. zillii and C. gariepinus in the Egyptian market, by studying proximate body composition, antioxidant enzyme activity, and bioaccumulation of some trace elements. In this study, T. zillii showed the highest mean of carbohydrates (16.11± 0.67 mg/g), fats (24.21 ± 0.93mg/g), ash (7.33 ±1.00 %), and water content (78.33 ± 1.85 %) whereas, the highest mean of protein content was recorded in C. gariepinus (64.33 ±1.01 mg/g). Antioxidant activity GSH (41.66 ± 2.01mg/g), CAT (21.66 ± 2.6 U/g), GPx (36.5 ± 3.01 mU/L), and GR (41.16 ± 1.0 U/L) in the liver of T. zillii demonstrated insignificant decrease, except GSH and CAT was significant at (p < 0.05). SOD activity showed an insignificant decrease in T. zillii (47±3.5 U/g). Concerning trace element concentrations, C. gariepinus demonstrated an increase in five trace elements than T. zillii. The abundance of the elements is in the order as Hg< Al < Cd T. zillii and C. gariepinus muscles. The highest As was recorded in C. gariepinus (1.54 ± 0.08 μg/g), whereas, the lowest Hg was recorded in T.zillii (0.47 ± 0.08 μg/g). In this research, the concentrations of the trace element in the two studied fish species were above the limits permitted by EOSQC, FAO/WHO, and the EU'. The estimated weekly intake (EWI) of the elements concentrated in the two fish species was unsafe for young people (40 Kg), and children (15 Kg), whereas it was safe for consumption by adults (70 kg) with advice on safe levels of consumption for C. gariepinus for adults. So, this study recommended that the children should consume less than 16.12857 g/day or 112.90 g/week T.zillii muscle and 13.27 g/day or 92.92 g/week C. gariepinus muscle. Moreover, Youth should consume less than 43.01 g/day or 301.7g/ week T.zillii muscle and 35.39714 g/day or 247.78 g/week C. gariepinus muscle. Finally, adult should consume less than 23.1 g/day and 161.7 g/week T.zillii muscle, and 61.94286 g/day or 433.6 g/week C. gariepinus muscle to maintain their safety.