Adding natural product such as Humic acid (Humabol) and Yucca schidigera extract to enhance water quality under scarce water exchange regiment; has numerus effects on both fish environment and health. Yucca showed significant reduction on NH 3 and NO 2 levels, while humic acid showed significant reduction on orthophosphate and total phosphorus compared to negative control; in addition to maintaining acceptable growth rate under designed experimental conditions. Furthermore, the hematological study showed that, Yucca and humic had positive effect on Red cell indices values such as, HCT, MCV, MCH, MCHC as well as WBCs total count and the proportion of the NEU, MONO, ESO and LYM of the treated treatments. Also, the histological study of gills, liver, stomach and intestine highlighted the tissue protective effect manifested by Yucca and humic.

The study was planned out to estimate the ractopamine (RAC) residues in frozen beef as well as the effect of different cooking on (RAC) in beef samples. The mean value of RAC in meat was 3.43±0.43 ppb. The obtained results showed no evidence for the illegal use of ractopamine, but these results do not exclude the possibility of misuse of these potentially harmful Substance. Regarding the effect of cooking on RAC residues in different cooking processes (boiling, microwaving and grilling), results showed that the degradation of RAC after boiling was 19.24%. Whereas after microwaving and grilling they were 11.66, 47.52%. The results were statistically evaluated and the public health significances were discussed.