الفهرس 
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Abstract
Fish isconsidered the most important and cheapest sources of animal protein in tropical and subtropical countries that suffer from lack of animal protein , so most people directed to consumption of it due to its low cost and its highest nutritive values.
In recent years, hormones and hormone–like compounds have been frequently used in fish farms toenhance the growth in a shorter period of timefor increasing the profits but the consumption of fish meat containing hormone residues especially synthetic hormones (17 alpha Methyltestosterone and Trenbolone acetate) may be potentially hazardous to human consumers.
So the aim of this study was planned out to estimate the MT and TBA residues in 100 samples of Tilapiawhich were collected randomly from different localities at Cairo and Giza markets, Egypt.
Samples were extracted and analyzed using Enzyme-linked immuno sorbent Assay (ELISA) method then confirmed using LC/MS/MS. The results show no significant variation between the two methods.
The results that obtained by ELISA in the case of MT revealed that the mean value in fish muscle was 2.06±0.20 ppb with minimum and maximum values of 1.4 and 3.1ppb.These result was confirmed by LC/MS/MS that revealed the mean value of MT 2.78±0.18ppb with minimum and maximum values of1.54 and 3.34ppb.
While the results that obtained by ELISA in the case of TBA revealed that themean value was 0.23±0.01 ppb with minimum and maximum values 0.1 and 0.4 ppb. These result was confirmed by LC/MS/MS which revealed that the mean value of TB 0.37±0.03 ppb with minimum and maximum values of0.26 and 0.52 ppb.
This study also detected the effect of different cooking methods(frying and grilling) on the level of the hormonal residues in fish samples and found that by frying and grilling the methyltestosterone and trenbolone acetate hormones were slightly decreased.
The level of MT hormone before frying with mean, minimum and maximum values of2.75±0.16 ,1.68 and 3.1ppb , respectively. But after frying the hormone residues slightly decreased with reduction percent 2.9% to became with mean, minimum and maximum values of2.67±0.15 , 1.56 and 2.92 ppb , respectively.There were significant difference (P<0.05) between MT residues before and after frying.
While the level of TBA hormone before fryingwith mean, minimum and maximum values of0.34±0.016 , 0.23 and 0.40 ppb, respectively. but after frying, the hormone residues slightly decreased with reduction percent of5.88% to become with mean, minimum and maximum values of0.32±0.015, 0.22 and 0.38 ppb, respectively. There were no significant difference (P<0.05) between TBA residues before and after frying.
By grilling, the level of MT hormone slightly decreased with reduction percent of2.54% to became with mean, minimum and maximum valuesof 2.68±0.15 , 1.65 and 3.04 ppb , respectively, but there was no significant difference (P<0.05) between MT residues before and after grilling.
While by grilling, the level of TBA hormoneslightly decreased with reduction percent 2.94% to became with mean, minimum and maximum values of 0.33 ±0.015, 0.23 and 0.39 ppb , respectively but there were no significant with any means.
Our results showed no evidence for the illegal use of hormones, but these results do not exclude the possibility of misuse of these potentially harmful hormones. Therefore, there is need to monitor these hormones as a food quality and health control measure.