Browsing by Author "Magana, Adiel"

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Characteristics of Waste Pickers in Nakuru and Thika Municipal Dumpsites in Kenya
(Journal of Applied Science and Technology, 2019-08-21) Kariuki, Joseph Maina; Bates, Margaret; Magana, Adiel
Dumpsite waste picking is prevalent in many developing countries of which Kenya is one. Waste pickers play an important role in waste recycling by recovering and providing materials to the waste recycling industry. Aim: The purpose of the study was to characterise the demographic and socio-economic factors of waste pickers in Nakuru and Thika municipal dumpsites. Study Design: The research design was a cross-sectional social survey and the sample size was 167. Place and Duration of Study: The study was carried out in the largest dumpsite in Nakuru and Thika towns found in Nakuru and Kiambu counties respectively. Methodology: The data was collected by use of structured questionnaire. The data was analysed using the Statistical Package for Social Sciences. Analysis was by frequency tables, χ2 test and ttest at 95% level of confidence. Results: The results show that there was parity by gender in Nakuru but in Thika the proportion of females was much higher than that of males. There was significant association between age and site of operation with waste pickers in Thika being on average younger than in Nakuru (χ = 12.605, d.f. = 3, p = 0.006). Waste pickers in Thika had on average attained a higher level of education than in Nakuru (χ2 = 12.352, d.f. = 3, p = 0.006). Most of the waste pickers (96%) only picked from exclusively from the dumpsite. Waste pickers in Thika spent an average of 10.26±0.23 hours daily in waste picking which was significantly higher (t=-3.709, n=160, p<.001) than at Nakuru (8.97±0.27 hours). The mean number of years of waste picking in Thika was significantly less than in Nakuru (t=4.627, d.f.=158, p<.001). Conclusion: In conclusion, waste pickers play an important role in waste recycling, with waste picking supporting hundreds of waste pickers in the study area, who are important in integrated waste management and need to be understood, appreciated and supported.
Modifying Surber sampling technique increases capture of freshwater crabs in African upland streams. Inland Waters. 2:11-15
(2017-04-03) Magana, Adiel; Dobson, Michael; Mathooko, Jude M.
We compared 2 methods for sampling the freshwater crab Potamonautes odhneri (Colosi) in Kenyan streams: standard Surber sampling, in which a sample is taken over a period of several minutes; and rapid Surber sampling, in which the process is reduced to around 10 seconds. Rapid Surber sampling caught more crabs than standard Surber sampling, This suggests that the crab species investigated is normally able to evade capture if sampling is carried out at an unhurried pace, but that if precision is sacrificed for speed, then capture efficiency increases. The size of crabs caught using the 2 techniques was similar, and use of baited traps set in the same locations showed that Surber sampling methods were not capturing larger individuals. Like all methods available to sample large benthic crustaceans, rapid Surber sampling has its limitations, but this study demonstrates that it can be used as a method for rapid assessment of crab presence and for comparative determination of population density, to significantly greater effect than the standard method of Surber sampling.
Performance of Nile Tilapia (Oreochromis niloticus) Fed Diets Containing Blood Meal as a Replacement of Fish Meal
(Canadian Center of Science and Education, 2016) Kirimi, James; Musalia, Levi; Magana, Adiel; Munguti, Jonathan
Abstract A 100 days experiment was conducted to determine the effect of feeding blood meal (BM) as a replacement of fish meal (FM), as the main source of animal protein, on growth rate and economic performance of Nile tilapia in fertilized pond. Three isonitrogenous diets (35% crude protein) were formulated using either FM as the main source of animal protein (Diet 1); 50% replacement of FM with blood meal (Diet 2); or 100% replacement of FM with BM (Diet 3). Three hundred Nile tilapia fingerlings (12±3 g) were randomly distributed into three groups of four replicates of 25 fingerlings per cage. The groups were randomly assigned the 3 diets which were fed at 2% of their biomass at 10 am and 4 pm every day. Percentage daily weight gain (DWG), relative growth rate (RGR), specific growth rate (SGR), survival rate and feed utilisation efficiency were measured. Fish fed diet 1 were larger (50.69 g) (P < 0.05) than those fed diet 2 (48.47 g) and 3 (40.37 g). Replacement of FM with 50% and 100% BM reduced the incidence cost (45.55, 37.83 and 31.88, respectively). The profit index was highest with 100% (9.42) replacement of FM, compared to 50% (7.95) and 0% (6.69). Although replacing FM with BM was associated with reduced growth, the economic return was better (P < 0.05). Based on the present results, it was economical to use BM as a major protein source instead of FM in formulating fish feed.
Protein Quality of Rations for Nile Tilapia (Oreochromis niloticus) Containing Oilseed Meals
(Canadian Center of Science and Education, 2020-01-15) G. Kirimi, James; M. Musalia, Levi; Magana, Adiel; M. Munguti, Jonathan
Considering price as the main limiting factor in the use of animal proteins, this study evaluated the protein quality of diets for Nile tilapia containing oilseed meals as replacements of fishmeal. A control diet (FMBD) (30% crude protein and 2900Kcal DE/kg) was formulated using fishmeal (FM), soybean meal (SBM), canola meal (CM) and sunflower meal (SFM). The test diets SBBD, CMBD and SFBD were formulated by replacing 10% CP of FM by SBM, CM and SFM, respectively. The amino acid profile was determined by MPA FT-NIR spectrometer (Bruker, Germany). Fishmeal recorded higher levels (p < 0.05) of lysine (7.81 mg/100 g), methionine (2.89 mg/100 g), arginine (5.87 mg/100 g), threonine (4.28 mg/100 g) and isoleucine (4.55 mg/100 g). The chemical score for all essential amino acid in fishmeal were higher than 100. Sunflower meal was a superior (p < 0.05) protein source with an essential amino acid index (EAAI) of 1.14 compared to CM (0.80) and SBM (0.70). Substituting FM with SBM, CM or SFM, reduced (p < 0.05) the levels of all amino acids apart from methionine which was increased (p < 0.05) in the diet with SBM substitute. In all diets, methionine and isoleucine were the first and second limiting amino acids, respectively. Though the diet containing FM exhibited higher (p < 0.05) EAAI (0.97), it was not satisfactory because it was limiting in methionine. The EAAI reduced (p < 0.05) with replacement of fishmeal by SBM (0.78), CM (0.77) and SFM (0.76). The study showed that the control diet had good quality protein and substitution with SBM, CM and SFM gave useful protein diets.
Synergistic Evaluation of Selected Plant Extracts on Potency of Pyrethrins against the Maize Weevil, Sitophilus zea-mais (MOTSCH.)
(Merit Res. J. Agric. Sci. Soil Sci., 2020) Michura, Anne Jerotich Garry; Magana, Adiel; Ochieng, Ombaka; Gachoka, Kennedy
The interest in utilization of botanical insecticides, particularly essential oils have become increasingly relevant in the control of insect pests. Many plant products and their bioactive compounds with repellent, antifeeding or insecticidal activity against stored product insect pests have been reported however, their levels of control are still wanting. The major issue is that the oil yields obtained are low, unstable and high costs involved in production to use on a commercial scale. Use of these oils in combinations or in formulations with botanical actives as synergists or stabilizers, may make them economically viable insecticides. The present study focussed on evaluating plant extracts (Black pepper seeds, Nutmeg seeds, coriander leaves and roots) as potential synergists in formulations with pyrethrins for possible use in protection of stored grains against Sitophilus zea-mais. Full dose response and synergism experiments were carried out on S. zea-mais at four concentrations of synergists at ratio 1:1 (synergist: pyrethrins) Topical application of synergist/ formulation on S. zea-mais was done in triplicate using Factorial Design in a completely Randomized Design layout. Experiments were conducted under controlled laboratory conditions of 27 ± 2OC and 60 ± 5%RH with normal day light hours. Probit analysis was used to determine the lethal concentration (LC) of pyrethrins and ANOVA was used to obtain the mean mortality differences of S. zea-mais at P ≤ 0.05. LC20 value for pyrethrins was found to be 2,200 ppm. In formulations of synergist: pyrethrins, coriander leaves extract (CLHE), Nutmeg seed extract (NMHE) and Black pepper seed methanol extract (BPSME) were statistically significant (P ≤ 0.05) 24 h after exposure. PBO registered higher percentage (83.33 ± 12.02%) mortality followed by CLHE (46.67 ± 3.33%), BPSME (43.33 ± 6.67%). BPSME and NMHE co-toxicity values were below 20 and -20 respectively while in PBO, BPSHE and CLHE values were above 20. Plant extracts BPSHE and CLHE and PBO synergized the toxicity of pyrethrins in all concentrations over 72 h exposure duration with co-toxicity factors above 100. BPSME was shown to be an additive in the formulation and only a synergist at 20,000ppm while NMHE was antagonistic to pyrethrins. Increasing the concentration of a plant extract did not correspond to increased efficacy of the formulation. Efficacy of the synergist- pyrethrins formulations at lower concentrations can be economically viable since average percentage mortalities will not be different from that of higher concentrations when time of interaction is prolonged. It is recommended that BPSHE and CLHE can be synergists to pyrethrins when formulations are exposed to insects for 72 h duration