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The aim of this study is to investigate the effect of oregano (Origanum vulgare) by different levels (control,0.05, 0.10, 0.15 and 0.20% Origanum vulgare) in Oreochromis niloticus diets on Growth performanceparameters, histology and chemical analysis of sex reversed males of Nile tilapia O. niloticus. Ten concreteponds 3x7 x lm (2l m3 for each – semi intensive culture) were used in this study. The ten ponds represented 5treatments (with 2 replicates for each treatment), and each pond was stocked with lo fish / m3 (2l0 fish for each pond)with an initial weights average ranged between 4.90 and 5.02 ± 0.67gm for five treatments, respectively.Fingerlings were fed at a rate of 5% of the total fish mass until the end of experimental period (l6 weeks). All dietscontained 30% crude protein and about 360 Kcal/100 g digestible energy. fish fed these diets twice daily for sixdays a week. The duration of the experiment was l6 weeks. The results obtained from this experiments showedthat: -The highest rate of final body weight (FBW), daily weight gain (DWG), final body length (FBL), specific growth rate (SGR) and protein efficiency ratio (PER), were recorded for the third treatment (0.10% Origanum vulgare). while, the first treatment (control) was recorded the lowest growth parameters (FBW, DWG, FBL, SGR and PER).The chemical composition for the whole fish, the second treatment was recorded the highest rate of protein% and the third treatment recorded the highest rate of fat% and the first treatment recorded the highest rate of ash%. As for the edible part of the fish, the second treatment was recorded the highest rate of protein and ash % and the third treatment recorded the highest rate of fat%. With regard for the Blood components, the fifth treatment had the highest rate of hemoglobin and creatinine and the third treatment was recorded the highest rate of red blood cells and the first treatment recorded the highest rate of liver functions and cholesterol. The second treatment recorded the highest rate of total protein and albumin.Based on the results obtained in this study, it can be concluded that the use of 0.10% oregano extract was best for growth, liver function and chemical composition under semi-intensive culture. |
