Browsing by Author "Kirimi, J. G."

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Carcass Fatty Acid Composition and Sensory Properties of Nile Tilapia (Oreochromis Niloticus) Fed on Oilseed Meals With Crude Papain Enzyme
(East African Journal of Science, Technology and Innovation, 2022) Kirimi, J. G.; Musalia, L. M.; Munguti, J. M.; Magana, A.
In this study, proximate body composition, fillets fatty acid and sensory properties of Nile tilapia fed on oilseed meals with crude papain enzyme were determined. A control diet (D1) of 300g/kg crude protein (CP) and (2900Kcal/kg) was formulated using fishmeal (Rastrionaebola argentea) (FM) and test diets by replacing 10% CP of FM by soybean meal (SBM) (D2), canola meal (CM) (D3) and sunflower meal (SFM) (D4). One hundred and one days feeding trial was conducted in a 4x2 factorial design on 4 diets (D1, D2, D3 and D4) with (0.06%) and (0%) enzyme using 720 Nile tilapia fingerlings (7±3g). Fish were fed twice daily at 5% of their biomass at 10am and 4pm in two equal meals. At the end of feeding trial, fish were starved for 24 hrs and weighed. A sample of ten fish representing the average weight of each replicated group was used. The fillets fatty acid profiles were determined by MPA FT-NIR spectrometer. Organoleptic tests of both fresh and steamed fish were carried out by eight semi trained panellists using 5-point hedonic scale. There was increase (p<0.05) in carcass proximate composition in all the treatments. Fillets fatty acid levels were influenced by the crude papain enzyme (p<0.05). Palmitic acid (C16:0), linoleic acid (C18:2n-6) and oleic acid (C18:1n-9) were the most abundant fatty acids in the fillets. Fish fed on fishmeal based diet recorded higher percentage (22.56) of polyunsaturated fatty acids (PUFA). There was significant difference among the treatments (p<0.05) for general appearance. Fish fed on crude papain enzyme treated diets were less preferred. It is recommended that more research be done on the effect of papain enzyme on the carcass fatty acid and sensory properties of farmed fish.
Effect of Substituting Fishmeal with Oilseed Meals on Diets Fatty Acid and Proximate Composition for Nile tilapia (Oreochromis niloticus)
(Journal of Agriculture and Veterinary Science, 2021) Kirimi, J. G.; Musalia, L. M.; Munguti, J. M.; Magana, A.
The study aimed to evaluate the fatty acid and proximate composition of diets for Nile tilapia containing soybean meal (SBM), canola meal (CM) and sunflower meal (SFM) as replacements of fishmeal (FM). A control diet (D1) of 30% crude protein (CP) was formulated using fishmeal as main protein source. The test diets (D2, D3 and D4) were formulated by replacing 10% CP of FM by SBM, CM and SFM, respectively. The fatty acid profile of ingredients and diets were determined by MPA FT-NIR spectrometer. FM displayed higher CP content (62.60%) followed by SBM (47.38%), CM (34.39%) and SFM (24.81%). SFM had highest crude fibre content (p<0.05) while CM displayed higher figure for ether extracts (p<0.05). Substituting FM with SBM, CM and SFM increased the levels of crude fibre (p<0.05). Diet 4 recorded highest crude fibre (16.03%) content (p<0.05), while CM based diet recorded highest ether extract content (10.75%), (p<0.05). Diet 1 had lowest concentration (21.85mg/100g) of total saturated fatty acid and D2 lowest concentration of polyunsaturated fatty acid (29.90mg/100g). The study revealed that 10% CP substitution of FM with SBM, CM and SFM in Nile tilapia diets is possible without much negative change in diets proximate and fatty acid composition.
Nile Tilapia (Oreochromis Niloticus Linnaeus, 1758) Culture in Kenya: Emerging Production Technologies and Socio-Economic Impacts on Local Livelihoods
(John Wiley & Sons Ltd., 2022) Munguti, J. M.; Nairuti, R.; Iteba, J. O.; Obiero, K. O.; Kyule, D.; Opiyo, M. A.; Abwao, J.; Kirimi, J. G.; Outa, N.; Muthoka, M.; Ogello, E. O.
Nile tilapia (Oreochromis niloticus) is one of the most farmed fish globally, with a signif- icant contribution improving local livelihoods, especially in developing countries. Nile tilapia was first cultured in Kenya in 1924 and is the most cultured fish species. Annu- ally, O. niloticus accounts for 62% (∼15,000 tonnes) of total aquaculture production. Although O. niloticus is the most preferred cultured fish, its culture faces challenges, for example, early maturation due to prolific breeding behaviour leading to stunted growth that limits its culture and profitability among smallholder farmers. With the surging demand for locally farmed fish, innovative technologies have emerged to boost aqua- culture production. Donor and public research-funded projects, for instance, the Kenya Climate Smart Agriculture Project, are validating various aquaculture technologies, innovations and management practices (TIMPs) to achieve ‘triple wins’ of increased fish production, improved resilience and reduced greenhouse gas emissions. In addi- tion, the International Fund for Agricultural Development (IFAD)-funded Aquaculture Business Development Programme aims at commercialising aquaculture to improve local livelihoods. In this study, we adopt a scoping review methodology to review and synthesise published literature on tilapia culture in Kenya to explore current and emerging tilapia production technologies and document their socio-economic impacts on farmers’ livelihoods. These emerging innovative technologies range from culture systems, for example, biofloc, periphyton, fingerpond technology, integrated aquacul- ture, breeding and genetics (selective breeding), fish health and biosecurity measures, to post-harvest loss reduction, value addition and marketing. The study findings reveal that the technologies have great potential to increase tilapia production and prof- itability and positively impact the local livelihoods of smallholder fish farmers through employment creation, economic growth and better nutrition.