Abstract:
This study was undertaken on-station at Magadu Research Farm, Sokoine University of Agriculture and on-farm at Changa and Kibwaya villages, Mkuyuni ward. The objective of the study was to evaluate growth performance of four tilapia species under culture conditions. The tilapia species used were Oreochromis niloticus, O. hornorum, O. ruvumae and O. jipe which were collected from Kingolwira Fish Farming Center, River Wami, River Ruvuma and Lake Jipe, respectively. Eight hapas (6m2 each) and six earthen ponds (50 to 200 m2) were used for the on-station and on-farm experiments respectively. Stocking density was 2 fish /m2 in both experiments. The experiment lasted for 90 days in both locations. Results from the present study indicated that, O. niloticus showed the highest final body weight (FBW) (67.6 ± 2.4g) and average daily gain (ADG) (0.7 ± 0.03g /day) in the on-farm experiment than in the on-station (27 ± 3.1g and 0.3 ± 0.04g /day). O. hornorum ranked second in both on-farm (41.2 ± 2.4 g, 0.4 ± 0.03 g/day) and on-station (26.4 g ± 3.8, 0.2 ± 0.04 g/day) experiments. O. ruvumae showed the lowest FBW and ADG in both on-farm (17.6 ± 2.4g, 0.15 g/day) and on-station (23.4 ± 3.3g, 0.2 ± 0.04 g/day) experiments. O. jipe showed the lowest FBW and ADG (16.3 ± 2.0g, 0.02g /day) among the species studied in the on-station experiment. The CP content in the fish body was highest (62.86 ± 2.5%) for O. niloticus reared on-station and lowest (52.23 ± 2.5%) for O. ruvumae reared on-farm. Ether extract (EE) was highest for O. hornorum in both experiments. Results from the present study proved the superiority of O. niloticus over other tilapia species followed by O. hornorum and O. ruvumae. O. jipe had the lowest growth performance, making the species unsuitable for aquaculture despite its highest survival rate.
