Alexander Shula Kefi | LILONGWE UNIVERSITY OF AGRICULTURE AND NATURAL RESOURCES (LUANAR) (original) (raw)
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Papers by Alexander Shula Kefi
Second RUFORUM Biennial Regional Conference on "Building capacity for food security in Africa", Entebbe, Uganda, 20-24 September 2010., 2010
International Journal of Innovative Research in Multidisciplinary Education
A study was carried out at the National Aquaculture Research and Development Centre, Fish Farm, t... more A study was carried out at the National Aquaculture Research and Development Centre, Fish Farm, to evaluate the effect of 17α-Methyltestosterone on the growth performance of fry of Oreochromis andersonii, Oreochromis macrochir and Oreochromis niloticus raised for a period of ninety day. The first 21 days, the fry (0.04g±0.001) across all treatments were fed on commercial feed incorporated with 17α-Methyltestosterone for the purpose of achieving sex reversal to all males and were held in 1m x 1m x 1.3 mhapas installed in a 400 m2 semi concrete pond, at a stocking density of 250 fry per hapa and replicated three times in a completely randomized design. There were no significant differences (P>0.05) in the final weight gain among the species of O. andersonii (1.8240±0.067g), O. macrochir (2.6830±0.3220g) and O. niloticus (2.3960±0.2230g). The Body weight gain (g), Specific growth rates (SGR) and Apparent feed conversion ratios didn’t significantly differ (P>0.05) among the treatm...
Fishes
The study investigated the management practices that contribute to disease outbreaks in farmed ti... more The study investigated the management practices that contribute to disease outbreaks in farmed tilapia in Lusaka and central and southern provinces in Zambia. It was a cross-sectional qualitative study undertaken from January to March 2021 in which questionnaires were administered to 49 farmers to assess their fish health management and biosecurity competence. Data were analysed using means, percentages, ratios, and logistical regression. The results showed that the majority of the farms had high stocking densities (>8 fish/m2, 44.4%), reared Nile tilapia (67.7%), and sourced water for farming from rivers and streams (45.7%). A few farmers measured water quality parameters daily (16.7%) and removed dead fish from ponds daily (20.8%). The stocking density (p = 0.013), fish species (p = 0.031), dead fish disposal methods (p = 0.023), and control of predator birds (p = 0.016) influenced the total mortality recorded on farms, while pond type (p = 0.031 and p = 0.045), water source (p...
Journal of Marine Science: Research & Development, 2014
A study was conducted using structured questionnaires and personal interviews to determine how im... more A study was conducted using structured questionnaires and personal interviews to determine how imported fish contributes towards reduction of fish deficit in Zambia. Data was collected from those involved in fish imports through two entry points into Zam-bia; namely Chirundu and Katima Mulilo, as well as the Department of Fisheries (DOF) headquarters in Chilanga. The site selection was based on the anticipated high level of fish imports coming from the Southern part of Zambia. This study has shown that the country imports up to 12% of all the fish consumed in Zambia, despite production from aquaculture having increased from 10 to 24%. The study further revealed that imported fish were of different preservation forms; Sun-died, Smoked, Salted, Frozen and chilled to prolong their shelf life. Frozen form constituted the largest amount, followed by salted and then chilled form. In terms of size preference , small fish of about 50g to 100g were mostly on demand in places of high populati...
Gender, Technology and Development, 2020
International Journal of Fisheries and Aquaculture, 2017
Sustainability, 2020
Few studies examine post-harvest fish losses using a gender lens or collect sex-disaggregated dat... more Few studies examine post-harvest fish losses using a gender lens or collect sex-disaggregated data. This mixed-methods study assessed fish losses experienced by female and male value chain actors in a fishery in western Zambia to determine who experiences losses, why, and to what extent. Results indicate that participation in the fishery value chain is gendered and most losses occur during post-harvest activities. Discussions with fishers, processors, and traders suggest the value chain is more fluid than often depicted, with people making calculated decisions to sell fresh or dried fish depending on certain conditions, and mostly driven by the need to avoid losses and attain higher prices. The study shows that gender norms shape the rewards and risks offered by the value chain. This could be the reason why a greater proportion of women than men experienced physical losses in our study sample. Female processors lost three times the mass of their fish consignments compared to male pr...
International Journal of Fauna and Biological Studies, 2016
A study was conducted to determine sex – dependent index of preponderance and condition factor of... more A study was conducted to determine sex – dependent index of preponderance and condition factor of Oreochromis andersonii in fertilized fish ponds. Fish (0.52±0.093g; mean ± SD) were stocked in semi – concrete ponds at 4 fish/m2 and were allowed to grow for 281 days. There was a negative allometry for both sexes since the ‘b’ factor was lower than 3 although females’ (3.773±0.069) coefficient of condition (K) was significantly (P<0.05) lower than that of males (3.972±0.040). Oreochromis andersonii females showed a logarithmic relationship between the heart (y = 0.037ln(x) 0.0836; R2 = 0.407; P<0.05) and liver (y = 0.2214ln(x) 0.1756; R2 = 0.317; P<0.05) weights and body weight while in males there were linear relationship for both heart (y = 0.0213 + 0.0009x; R2= 0.406, P<0.05), and liver (y = 0.0459 + 0.0097x; R2= 0.40, P<0.05). A power relationship was observed between length – weight relationship for both sexes (female = y = 0.0001x2.7672; R2 = 0.943; P<0.05 and ...
Journal of Marine Science: Research & Development, 2013
ABSTRACT The aim of the study was to investigate the effect of 17 α-methyl testosterone (MT) on h... more ABSTRACT The aim of the study was to investigate the effect of 17 α-methyl testosterone (MT) on haematology and histology of liver and heart of Oreochromis andersonii subjected to varying levels of MT. Three different doses (40, 60 and 90 mgMT/kg feed) of MT were administered to O. andersonii. Final mean weight (g), gonadosomatic, cardiosomatic and hepatosomatic indices did not differ (P>0.05) among the treatments. Similarly, survival of the O. andersonii in all the treatments did not differ (P>0.05) significantly. Of the haematological and blood chemistry parameters determined, only haemoglobin (Hb), red blood cells (RBC), haematocrit and uric acid were significantly different (P<0.05), among the treatments with the control group having the highest of the latter two parameters. Haemoglobin (r=-0.743; P<0.05) and Red Blood Cells (RBC) (r=-0.726; P<0.05) showed significant association with MT levels. All the treatments did not show any histopathological differences in the liver and heart. However, all the liver samples showed haemosidrein (HE) and extra–hepatic pancreas (EH), while the heart exhibited the vacuolar degeneration (VD). The length–weight relationship coefficient differed (P<0.05) among the treatments with the fish fed with 40 mgMT/kg having the highest slope (2.642), although it only differed (P<0.05) with that of 90 mgMT/kg (1.547), which exhibited the worst condition. The study shows that the oral administration of MT for a short period of up to thirty (30) days does not affect the physiology of O. andersonii. Furthermore, the safety of MT to O. andersonii is, therefore, proved under the conditions of the current experiment. However, there are signs of condition deterioration in high levels of MT.
Ecology and Society, 2018
International Journal of Fisheries and Aquaculture, 2018
International Journal of Fisheries and Aquaculture, 2016
Experiments to investigate the use of activated carbon to remove ammonia in aquaculture were cond... more Experiments to investigate the use of activated carbon to remove ammonia in aquaculture were conducted at the National Aquacul-ture Research and Development Centre (NARDC), Kitwe, Zambia. The activated carbon was produced from the maize cob residue. The raw material was carbonized by partial combustion with limited amount of air. The carbonized material was then activated using steam at a pressure of 1.8 × 10 5 KPa and was later processed into powder and granular activated carbon. Each of the four 100 litre experimental water tanks were stocked with 10 fingerlings of an average weight of about 12g and fed with a 40% crude protein feed at 10% of body weight per day. Three (3) hours after stocking, water samples were taken and tested for ammonia. All the four tanks indicated positive results for the presence of ammonia with an average amount of 0.05mg/l. Twenty (20) grams of granular activated carbon was applied to the three treatment tanks after the first three hours, the fourth tank...
Journal of Aquaculture Research & Development, 2012
![Research paper thumbnail of Effect of Dietary Soyabean [Glycine max (L.) Merr.] Protein Level on Growth and Feed Utilization of Oreochromis andersonii (Castelnau, 1861)](https://attachments.academia-assets.com/84892148/thumbnails/1.jpg)
](Pakistan Journal of Nutrition, 2013
Second RUFORUM Biennial Regional Conference on "Building capacity for food security in Africa", Entebbe, Uganda, 20-24 September 2010., 2010
International Journal of Innovative Research in Multidisciplinary Education
A study was carried out at the National Aquaculture Research and Development Centre, Fish Farm, t... more A study was carried out at the National Aquaculture Research and Development Centre, Fish Farm, to evaluate the effect of 17α-Methyltestosterone on the growth performance of fry of Oreochromis andersonii, Oreochromis macrochir and Oreochromis niloticus raised for a period of ninety day. The first 21 days, the fry (0.04g±0.001) across all treatments were fed on commercial feed incorporated with 17α-Methyltestosterone for the purpose of achieving sex reversal to all males and were held in 1m x 1m x 1.3 mhapas installed in a 400 m2 semi concrete pond, at a stocking density of 250 fry per hapa and replicated three times in a completely randomized design. There were no significant differences (P>0.05) in the final weight gain among the species of O. andersonii (1.8240±0.067g), O. macrochir (2.6830±0.3220g) and O. niloticus (2.3960±0.2230g). The Body weight gain (g), Specific growth rates (SGR) and Apparent feed conversion ratios didn’t significantly differ (P>0.05) among the treatm...
Fishes
The study investigated the management practices that contribute to disease outbreaks in farmed ti... more The study investigated the management practices that contribute to disease outbreaks in farmed tilapia in Lusaka and central and southern provinces in Zambia. It was a cross-sectional qualitative study undertaken from January to March 2021 in which questionnaires were administered to 49 farmers to assess their fish health management and biosecurity competence. Data were analysed using means, percentages, ratios, and logistical regression. The results showed that the majority of the farms had high stocking densities (>8 fish/m2, 44.4%), reared Nile tilapia (67.7%), and sourced water for farming from rivers and streams (45.7%). A few farmers measured water quality parameters daily (16.7%) and removed dead fish from ponds daily (20.8%). The stocking density (p = 0.013), fish species (p = 0.031), dead fish disposal methods (p = 0.023), and control of predator birds (p = 0.016) influenced the total mortality recorded on farms, while pond type (p = 0.031 and p = 0.045), water source (p...
Journal of Marine Science: Research & Development, 2014
A study was conducted using structured questionnaires and personal interviews to determine how im... more A study was conducted using structured questionnaires and personal interviews to determine how imported fish contributes towards reduction of fish deficit in Zambia. Data was collected from those involved in fish imports through two entry points into Zam-bia; namely Chirundu and Katima Mulilo, as well as the Department of Fisheries (DOF) headquarters in Chilanga. The site selection was based on the anticipated high level of fish imports coming from the Southern part of Zambia. This study has shown that the country imports up to 12% of all the fish consumed in Zambia, despite production from aquaculture having increased from 10 to 24%. The study further revealed that imported fish were of different preservation forms; Sun-died, Smoked, Salted, Frozen and chilled to prolong their shelf life. Frozen form constituted the largest amount, followed by salted and then chilled form. In terms of size preference , small fish of about 50g to 100g were mostly on demand in places of high populati...
Gender, Technology and Development, 2020
International Journal of Fisheries and Aquaculture, 2017
Sustainability, 2020
Few studies examine post-harvest fish losses using a gender lens or collect sex-disaggregated dat... more Few studies examine post-harvest fish losses using a gender lens or collect sex-disaggregated data. This mixed-methods study assessed fish losses experienced by female and male value chain actors in a fishery in western Zambia to determine who experiences losses, why, and to what extent. Results indicate that participation in the fishery value chain is gendered and most losses occur during post-harvest activities. Discussions with fishers, processors, and traders suggest the value chain is more fluid than often depicted, with people making calculated decisions to sell fresh or dried fish depending on certain conditions, and mostly driven by the need to avoid losses and attain higher prices. The study shows that gender norms shape the rewards and risks offered by the value chain. This could be the reason why a greater proportion of women than men experienced physical losses in our study sample. Female processors lost three times the mass of their fish consignments compared to male pr...
International Journal of Fauna and Biological Studies, 2016
A study was conducted to determine sex – dependent index of preponderance and condition factor of... more A study was conducted to determine sex – dependent index of preponderance and condition factor of Oreochromis andersonii in fertilized fish ponds. Fish (0.52±0.093g; mean ± SD) were stocked in semi – concrete ponds at 4 fish/m2 and were allowed to grow for 281 days. There was a negative allometry for both sexes since the ‘b’ factor was lower than 3 although females’ (3.773±0.069) coefficient of condition (K) was significantly (P<0.05) lower than that of males (3.972±0.040). Oreochromis andersonii females showed a logarithmic relationship between the heart (y = 0.037ln(x) 0.0836; R2 = 0.407; P<0.05) and liver (y = 0.2214ln(x) 0.1756; R2 = 0.317; P<0.05) weights and body weight while in males there were linear relationship for both heart (y = 0.0213 + 0.0009x; R2= 0.406, P<0.05), and liver (y = 0.0459 + 0.0097x; R2= 0.40, P<0.05). A power relationship was observed between length – weight relationship for both sexes (female = y = 0.0001x2.7672; R2 = 0.943; P<0.05 and ...
Journal of Marine Science: Research & Development, 2013
ABSTRACT The aim of the study was to investigate the effect of 17 α-methyl testosterone (MT) on h... more ABSTRACT The aim of the study was to investigate the effect of 17 α-methyl testosterone (MT) on haematology and histology of liver and heart of Oreochromis andersonii subjected to varying levels of MT. Three different doses (40, 60 and 90 mgMT/kg feed) of MT were administered to O. andersonii. Final mean weight (g), gonadosomatic, cardiosomatic and hepatosomatic indices did not differ (P>0.05) among the treatments. Similarly, survival of the O. andersonii in all the treatments did not differ (P>0.05) significantly. Of the haematological and blood chemistry parameters determined, only haemoglobin (Hb), red blood cells (RBC), haematocrit and uric acid were significantly different (P<0.05), among the treatments with the control group having the highest of the latter two parameters. Haemoglobin (r=-0.743; P<0.05) and Red Blood Cells (RBC) (r=-0.726; P<0.05) showed significant association with MT levels. All the treatments did not show any histopathological differences in the liver and heart. However, all the liver samples showed haemosidrein (HE) and extra–hepatic pancreas (EH), while the heart exhibited the vacuolar degeneration (VD). The length–weight relationship coefficient differed (P<0.05) among the treatments with the fish fed with 40 mgMT/kg having the highest slope (2.642), although it only differed (P<0.05) with that of 90 mgMT/kg (1.547), which exhibited the worst condition. The study shows that the oral administration of MT for a short period of up to thirty (30) days does not affect the physiology of O. andersonii. Furthermore, the safety of MT to O. andersonii is, therefore, proved under the conditions of the current experiment. However, there are signs of condition deterioration in high levels of MT.
Ecology and Society, 2018
International Journal of Fisheries and Aquaculture, 2018
International Journal of Fisheries and Aquaculture, 2016
Experiments to investigate the use of activated carbon to remove ammonia in aquaculture were cond... more Experiments to investigate the use of activated carbon to remove ammonia in aquaculture were conducted at the National Aquacul-ture Research and Development Centre (NARDC), Kitwe, Zambia. The activated carbon was produced from the maize cob residue. The raw material was carbonized by partial combustion with limited amount of air. The carbonized material was then activated using steam at a pressure of 1.8 × 10 5 KPa and was later processed into powder and granular activated carbon. Each of the four 100 litre experimental water tanks were stocked with 10 fingerlings of an average weight of about 12g and fed with a 40% crude protein feed at 10% of body weight per day. Three (3) hours after stocking, water samples were taken and tested for ammonia. All the four tanks indicated positive results for the presence of ammonia with an average amount of 0.05mg/l. Twenty (20) grams of granular activated carbon was applied to the three treatment tanks after the first three hours, the fourth tank...
Journal of Aquaculture Research & Development, 2012
Pakistan Journal of Nutrition, 2013