The experiment was conducted at the Misamfu Aquaculture Research Station in Kasama, Zambia. Fifteen (15) concrete tanks measuring 2 m2 each were used. There were four (4) treatments: Diet + Rosemary (DR), Diet + Garlic (DG), Diet + Turmeric (DT), and Diet with no additives (control) were fed to tilapia, Oreochromis machrochir , and each treatment was replicated three times.
The final mean weight, weight gain, and SGR of juveniles of O. machrochir fed on different diets ranged from 24.25 0.10g to 27.88 0.2g, 16.95 0.22g to 20.44 0.4g, and 2.00 0.21% per day to 2.2 0.11% per day, respectively. Lower final mean weight, weight gain and SGR were recorded in treatment where O. machrochir was fed on a diet without any feed additives, which differed significantly from diets supplemented with rosemary, garlic, and turmeric, which did not differ from each other. There was no significant difference in the FCR of O. machrochir fed on Diet + Rosemary, Diet + Garlic, and Diet + Turmeric. The survival rate varied from 90% to 93%, with a significantly (P<0.05) higher rate in fish fed on rosemary and garlic supplements, followed by a diet supplemented with turmeric, which did not significantly differ (P>0.05) from each but from fish fed on a diet without additives. Water quality parameters revealed to have no significant different among the treatments