Browsing by Author "Mnembuka, Berno V"

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Develop feeding strategies for moringa oleifera and leucaena leucocephala as protein sources in tilapia diets
(2011) Lochmann, Rebecca; Engle, Carole; Kasiga, Tom; Chenyambuga, Sebastian W; Shighulu, Hegi; Madalla, Nazael; Mnembuka, Berno V; Quagrainie, Kwamena
Digestibility and feeding trials were performed to evaluate Moringa oleifera and Leucaena leucocephala leaf meals as protein sources (compared to soybean meal) in Nile tilapia diets. Both leaf meals were obtained from Tanzania. The leaf meals were soaked in water to reduce anti-nutritional factors, dried, and ground to a small particle size before incorporation into diets. Five diets were made for both trials: the control diet contained 50% soybean meal (SOY), and diets 15 MOR and 30 MOR were made by substituting 15 and 30% of the soybean protein with Moringa protein. Diets 15 LEU and 30 LEU were made by substituting 15 and 30% of the soybean protein with Leucaena protein. For the digestibility trial, diets containing 32% crude protein were used. Diets with 36% protein were used for the feeding trial due to the small initial fish size. The digestibility trial was carried out using mixed sex Nile tilapia of 200-400 g in 150-L indoor tanks in a recirculating system with dechlorinated municipal water maintained at 28 0 C. Other water quality parameters were kept at optimum levels for Nile tilapia. Fish were conditioned to the experimental diets and the fecal removal process (fresh, floating feces were collected with a net) for 1 week. Fecal collection was conducted 8-10 hours after the last meal in the evening, as well as the next morning before feeding. The fecal samples were dried at 50 0 C for 12 hours and then frozen until analysis. The apparent protein digestibility (APD, mean+SE, %) of the SOY diet (86.35±0.87) was higher than all others. The APD of the 15 MOR (84.69±0.59) and 30 MOR (83.34±1.10) diets were similar to each other and higher than the APD of the 15 LEU (78.49±0.91) and 30 LEU (74.70±0.52) diets. The APD of 30 LEU was also lower than that of the 15 LEU diet. Overall, leaf meals reduced protein digestibility compared to soybean meal, but diets containing Moringa were digested better than those containing Leucaena. There was no difference in the apparent lipid digestibility (%) of the SOY (95.83±0.34) and 15 MOR (95.19±0.62) diets. Lipid digestibility of the SOY diet was higher than that of 30 MOR (92.99±1.17), 15 LEU (94.46±0.06), and 30 LEU (92.98±0.24) diets. Lipid digestibility of the 30 MOR and 30 LEU diets was lower than that of the other diets. Both protein and lipid digestibility were inversely related to concentration of dietary fiber. For the feeding trial, 100 mixed-sex Nile tilapia, averaging 5.16 g individually were stocked in 1500-L outdoor circular plastic tanks supplied with reservoir water. The tanks were maintained as static systems except for periodic flushing when water quality parameters fell below the optimum for Nile tilapia. Subsamples of 30-50 fish were weighed every two weeks and water quality parameters were monitored weekly. The trial was terminated after 60 days. There were no differences in growth, feed conversion, survival, lysozyme, or proteolytic enzyme activity among treatments. Proximate and fatty acid composition of whole fish is still in progress.
Evaluation of performance of different tilapia species
(University of Arkansas, 2011) Chenyambuga, Sebastian W; Meiluidie, Ester; Madalla, Nazael; Mnembuka, Berno V; Lochmann, Rebecca
A growth trial was carried out for 90 days to compare the growth performance and survival rate of Nile tilapia (Oreochromis niloticus) and Jipe tilapia (Oreochromis jipe), Wami tilapia (Oreochromis urolepis hornorum) and Ruvuma tilapia (Oreochromis ruvumae).. The study was conducted on-station at Sokoine University of Agriculture (SUA) and on-farm in ponds of small-scale fish farmers at Mkuyuni, Morogoro, Tanzania. In the on-farm experiment, the mean final weight, weight gain, growth rate, final length and final width differed significantly (P<0.001) among the species. Nile tilapia (O. niloticus) gained more weight (61.3g) than O. hornorum (35.3g) and O. ruvumae (13.8g). The final weight, length and width of O. niloticus exceeded that of O. hornorum by 26.2g, 2.4cm and 0.7cm, respectively. The mean final weight, length and width of O. hornorum were higher than those of O. ruvumae by 23.6g, 2.7cm and 1cm, respectively. The results from the on-station experiment showed that there was no significant (P>0.05) difference between O. niloticus and O. hornorum, but the two species differed significantly (P<0.01) from O. ruvumae and O. jipe. The O. niloticus had the highest weight gain (24.2 g), growth rate (0.3g/d), final length (11.5cm) and final width (3.3cm) and it was followed by O. hornorum. The O. ruvumae and O. jipe showed poor performance in all parameters. The growth performances of O. niloticus and O. hornorum were significantly (P<0.05) higher in the on-farm experiment than in the on-station experiment, but that of O. ruvumae were not significantly (P≥0.05) different between the two locations. The highest survival rates (85.6% (on-farm) and 100% (on-station)) were observed on O. niloticus, followed by O. ruvumae. Oreochromis urolepis hornorum had the lowest survival rate (63.5 – 66.7%) in both experiments. For all species, fish reared at the on-station showed higher survival rate (66.7 – 100%) compared to those reared in farmers’ ponds (63.5 – 85.6%). The results for chemical composition of the fish bodies indicated that the species did not differ significantly in dry matter (DM) and ash contents, but differed significantly (P<0.05) in crude protein (CP) and fat (EE) contents for the on-farm experiment. Oreochromis urolepis hornorum had the highest CP content (58.09%) and EE (30.12%) while O. niloticus had the lowest values (52.23% CP and 16.83% EE). For the on-station experiment, the DM, CP and ash contents of the species were not significantly (P≥0.05) different. It is concluded that Oreochromis niloticus is superior to Oreochromis urolepis hornorum, Oreochromis jipe, and Oreochromis ruvumae in terms of growth performance and survival rate.
Management and value chain of nile tilapia cultured in ponds of Small-scale farmers in Morogoro region, Tanzania
(2012) Chenyambuga, Sebastian W; Madalla, Nazael A; Mnembuka, Berno V
A study was carried out to assess production performance and value chain of Nile tilapia grown in ponds of small-scale farmers in Morogoro region, Tanzania. Information was collected through individual interviews of 30 fish farmers. The main reasons for culturing fish were provision of animal protein food for home consumption (66.7%) and generation of income (23.3%). Fish farming contributed 10.6% of household annual income and was ranked second to crop production (50%). The majority of the farmers were fertilizing their ponds with chicken manure (30.0%) and cattle manure (23.3%). Most farmers (73.3%) cultured pure stand of Nile tilapia and only few (26.7%) practiced polyculture of Nile tilapia and African catfish. All farmers depended on natural food as a source of feed for their fish. Moreover, the farmers were feeding maize bran (96.7%), vegetables (66.7%), and kitchen leftovers (13.3%) as supplementary feeds. Men were responsible for purchasing and stocking fingerlings (60.0%), feeding (40.0%), pond maintenance (53.3%), harvesting (60.0%) and selling (43.3%). Women were mainly involved in fish processing (76.7%). The average period from stocking to harvesting was 5.75 ± 0.18 months for Nile tilapia and the mean yield was 6,946.2 kg/ha per year. About 22.2% of the harvested fish were consumed at home and the remaining (77.8%) were sold. The main actors in the value chain of cultured Nile Tilapia were fingerling producers, fish farmers and consumers. Most farmers sold fresh fish directly to neighbours (70.0%) and consumers in the local market within the village (30.0%). It is concluded that small-scale fish farming is important for provision of animal protein food and income and is done mostly by men, and it is characterized by low productivity due to improper pond fertilization and feeding. The major problems to Nile tilapia farming under small-scale fish farming is lack of funds, stunted growth of stocked fish, inadequate knowledge on fish farming and unavailability of concentrate feeds.