School of Natural Resources and Environmental Studies
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Item Assessment of Growth Performance of Monosex Nile Tilapia (Oreochromis Niloticus) in Cages Using Low-Cost, Locally Produced Supplemental Feeds and Training Fish Farmers on Best Management Practices in Kenya(2018) Bundi, James M.; Ngugi, Charles C.; Fitzsimmons, Kevin; Manyala, Julius; Kimotho, Ann N.; Amadiva, Judith M.; Ndogoni, Julius N.; Munguti, JonathanChanging technology in aquaculture has been the major driving force for increasing aquaculture production in the phase of dwindling open water stocks. The choice of technologies and their adoption still remain a focus to increase production, productivity and farm incomes. We assessed the growth of Nile tilapia using locally available materials that included cages and low cost feeds to increased tilapia production in ponds. Various interventions were used among them experimental trials where we formulated low cost diets replacing expensive fish meal. A series of four workshops were also conducted over the course of this project period under this intervention. The first workshop on the development and use of best management practices in aquaculture was held in August 2014. This workshop targeting women in aquaculture had 18 women in attendance. There were two subsequent workshops, held in March and August 2015, and attended by fish farmers from Kirinyaga County. The fourth workshop was held for two days between 2nd and 3rd October 2015. This workshop specifically targeted the youth in aquaculture aimed at training the youth on integrated cage and pond culture focusing on development of cage culture in reservoirs located in the county of Kirinyaga that are presently underutilized by the communities. Graduate support covered three female students who selected because of their previous linkage with AquaFish CRSP and excellent role they continue to play in development of aquaculture in this region. Among them two have submitted their theses for examination. We submitted five peer reviewed publications during this project period with two being specific on low cost feed and fish meal replacement. AquaFish provided funds for HCPIs and graduate students to attend National, Regional and WAS Meetings and Conferences as well. We note that farmers adopted feed technology very well and in their survey feed formulation and fish breeding were their priority. Under lesson learned, we noted that farmers required frequent visits, simple materials for reading and constant communication. They also require strategies on fish marketing such as use of cell phones applications and Aquashops.Item Characterization of the nutritional quality of amaranth leaf protein concentrates and suitability of fish meal replacement in Nile tilapia feeds(Elsevier, 2017) Okoth, Elijah Oyoo; Ngugi, Charles C.; Manyala, Julius O.; Fitzsimmons, Kevin; Kimotho, AnnA number of leafy vegetables,their protein concentrates and hydrolasates are under evaluation as alternative protein ingredients to fish meal(FM)in aqua feeds. This study evaluated the nutritional characteristics and suitability of replacing FM with the amaranth (Amaranthus hybridus)leaf protein concentrates (ALPC) as a protein ingredient in the diet of Nile tilapia (Oreochromis niloticus). Experimental diets were formulated, where 100%, 75%, 50%, 40%, 20% and 0% FM protein was substituted by protein from ALPC. The six dietary treatments were tested in triplicate in static flow-through tanks. The substitution effects were compared in terms of fish growth performance, nutrient utilization, whole body composition and apparent nutrient digestibility. After 160 days of feeding, the growth, nutrient utilization and Feed Conversion Ratio (FCR) in fish fed diets containing 100%, 75%, 50%, 40% and 20% FM were better (P < 0.05) than those fed diet with 0% FM. The Apparent nutrient digestibility was high for protein, lipid and energy and differed significantly among the dietary treatments (P < 0.05). Protein digestibility in fish was highest in feed formulated with 100%, 75%, 50% and 40% FM, which were significantly (P < 0.05) higher than at 25% and 0% FM. Lipid digestibility was comparable for all the diets except fish fed 0% FM. Digestible carbohydrates and dry matter were similar for all dietary treatments (P < 0.05). We demonstrate that it is possible to replace up to 80% of fish meal with ALPC without compromising the performance O. niloticus. These results demonstrate that although it is possible to replace large part of fish meal with ALPC, it is not possible to eliminate it in Nile tilapia diet as alternative protein ingredient