Applied Biology and Biochemistry

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Activities of glutamate dehydrogenase and aspartate and alanine aminotransferases in freshwater snails Helisoma duryi and Lymnaea natalensis exposed to copper.
(Biomarkers, 2003) Masola, B.; Chibi, M.; Naik, Yogeshkumar S.; Kandere, E.; Zaranyika, M.F.
In this paper we investigate the potential of glutamate dehydrogenase (GDH) and aspartate and alanine aminotransferases (AST and ALT) as biomarkers of water pollution due to copper in the freshwater snails Helisoma duryi and Lymnaea natalensis. Snails were dosed with copper(II) ion concentrations of 0.01, 0.1 and 1 mg kg(-1) breeding water for a period of 96 h, after which those surviving were shelled. The copper content in the breeding water, in whole snail tissue and in the snail shells was determined at the end of the period of exposure. For enzyme determinations, whole snail tissue was first homogenized and fractionated by centrifugation at 500 g to remove the nuclei. The resulting supernatant was then centrifuged at 10,000 g to give a pellet fraction representing the mitochondrial fraction and a supernatant representing the cytosolic fraction. Copper was very toxic to both snail species at concentrations above 0.2 mg l(-1), with only 3% of the Helisoma and 12% of the Lymnaea surviving at concentrations of approximately 1 mg l(-1). The copper content in the shells and tissues of snails rose with increasing copper concentration in the breeding water, and was 2.1- to 4.9-fold in snails exposed to copper ion at a dose of 1 mg kg(-1) water compared with undosed snails. Similarly, the activities of GDH and AST rose by up to 4.7-fold in the homogenate and the mitochondrial and cytosolic fractions with increasing concentrations of copper. These activities, however, fell at copper concentrations of approximately 1 mg l(-1), which coincided with massive death of snails. Mitochondrial ALT disappeared at copper ion concentrations of approximately 0.2 mg l(-1) for Lymnaea and 1 mg l(-1) for Helisoma, possibly indicating mitochondrial degeneration. These results show that GDH, AST and ALT have the potential to be biomarkers of sublethal copper pollution in these two snail species, since their activities were significantly altered by low copper concentrations.
Aflatoxin Carryover during Large Scale Peanut Butter Production.
(Scientific Research, 2011-04) Siwela, Andrew H.; Mukaro, Kudzayishe J.; Nziramasanga, Nozipho
Peanut butter was monitored for aflatoxin contamination at different stages during its large-scale production starting from raw shelled peanuts up to the final product. Twenty five samples, weighing 2 kg each, were taken from each of the following stages: roasting at 160°C, blanching/de-skinning and grinding. The sub-samples were ground, thoroughly mixed and further reduced by the quartering technique until a 1 kg sub-sample was obtained. This was then analyzed for aflatoxins using reverse phase HPLC incorporating pre-column trifluoroacetic acid derivatization. The results showed a total aflatoxin percentage reduction of 51% after roasting, 27% after blanching/de-skinning followed by a further 11% after grinding to make peanut butter. This meant that there was a cumulative total reduction of 89% of aflatoxin concentration during the production process of peanut butter. These results show that there is a significant reduction of aflatoxin levels at the roasting and blanching stages in the process of producing peanut butter.
Aflatoxin Contamination of Stored Groundnuts in Zimbabwe.
(ICRISA T (International Crops Research Institute for the Semi-Arid Tropics)., 1989) Siwela, Andrew H.; Caley, A.D.
Aflatoxins were analyzed in groundnuts stored for either local or export sales in the period 1982/83 to 1986/87. Four hundred and forty-one samples of seven groundnut varieties were collected for analysis. Sixty-eight percent of the samples had total concentrations of aIlatoxin BJ and OJ of up to 25 JIg kg-J. In the 1986/87 groundnut crop, the Flamingo and Makulu Red varieties, which constitute the bulk of export sales, had up to 25 JIgkg-J aIlatoxin BJin 79%of the samples, plus aIlatoxin OJ in 67% of the samples. Overall, the Egret variety was the most susceptible to aIlatoxin contamination during this period.
Alteration of some Hepatic Enzyme Activities by Gastrointestinal Helminth Parasites in Domesticated Ostritches.
(Society of Education, 2013-05-05) Siwela, Andrew H.; Motsi, Leonah R.; Dube, S.
Using the conventional methods for parasitological examinations of the salt floatation and direct smear, ten ostriches infected with internal parasites were identified. Ten birds that were without internal parasites were used as the controls. The metabolizing enzymes glutathione peroxidase (GPX), DT -diaphorase (DTD) and succinate dehydrogenase (SDH) were assayed accordingly using liver samples from the control and infected birds. Malondialdehyde (MDA), a marker of lipid peroxdation, was also assayed. Results showed that cestode eggs occurred at twice the amount of nematode eggs in the faeces of infected ostriches. Infected birds showed significantly higher DTD activity when compared to non-infected birds (Student’s t test, p < 0.05) whilst the activities of SDH and GPX were statistically not altered (Student’s t test p > 0.05). MDA levels were significantly elevated in infected birds compared to controls (Student’s t test, p < 0.001). These results suggest that infected birds are under oxidative stress due to the parasitic infection . Key words: Cestodes, nematodes, glutathione peroxidase, DT-diaphorase, Succinate dehydrogenase, malodialdehyde
Altered Esterase Activity Due To Pesticide Exposure In The Aquatic Snail Physa Acuta.
(2013-03-14) Maredza, Alice; Naik, Yogeshkumar S.
The effect ofpesticides on the xenobiotic metabolising enzymes of the aquatic snail Physa acuta was studied. Adult snails reared in the laboratory were exposed daily for three days to the following pesticides: 2,4-dichlorophenoxyacetic acid, deltamethrin, endosulphan, malathion and pirimiphos-methyl. Cytosolic fractions prepared from the snails showed that pesticide exposure had no effect on the glutathione or glutathione dependent enzyme activities. General esterase activity using two different substrates was reduced significantly by exposure to the organophosphate pesticides malathion and pirimiphos. Exposure to the other pesticides did not cause any substantial changes in the esterases activities. The nature of this inhibition is not yet apparent. It is likely, however, that the changes are due to a competitive type inhibition by the pesticides for the active site of the enzyme.
Altered esterase activity due to pesticide exposure in the aquatic snail Physa acuta.
(2013-09-24) Maredza, Alice; Naik, Yogeshkumar S.
The effect of pesticides on the xenobiotic metabolising enzymes of the aquatic snail Physa acuta was studied. Adult snails reared in the laboratory were exposed daily for three days to the following pesticides: 2,4-dichlorophenoxyacetic acid, deltamethrin, endosulphan,malathion and pirimiphos-methyl, Cytosolic fractions prepared from the snails showed that pesticide exposure had no effect on the glutathione or glutathione dependent enzyme activities. General esterase activity using two different substrates was reduced significantly by exposure to the organophosphate pesticides malathion and pirimiphos. Exposure to the other pesticides did not cause any substantial changes in the esterases activities. The nature of this inhibition is not yet apparent. It is likely, however, that the changes are due to a competitive type inhibition by the pesticides for the active site of the enzyme.
Antibiotic Resistance Patterns and Virulence Factors of Coagulase Negative Staphylococcus Associated with Urinary Tract Infections in Bulawayo Province, Zimbabwe
(SCIENCEDOMAIN international, 2016) Mbanga, Joshua; Masuku, Sithabile; Luphahla, Silence
Aims: To determine the antibiotic resistance patterns and virulence factors of coagulase negative Staphylococcus (CoNS) associated with urinary tract infections (UTIs). The virulence factors assayed for were the atl E and ica AB genes. The prevalence of the antibiotic resistance gene, mec A, was also determined. Place and Duration of Study: Southern Pathology Clinical Laboratories and the National University of Science and Technology microbiology department, between December 2012 and March 2015. Methods: A total of 754 urine samples were analyzed for bacteria by standard procedures. Fromthese, 126 isolates were positively identified as CoNS. Antimicrobial susceptibility testing of the isolated CoNS was done using the disc diffusion method.The polymerase chain reaction (PCR) was also carried out to detect the presence of the mec A, ica AB and atl E genes. Results: Antibiogram profiles showed that CoNS had high prevalences of resistance to nalidixic acid (88.1%), cotrimoxazole (72.2%) and oxacillin (69.8%).There were however high prevalences of sensitivity to nitrofurantoin (79.4%) and gentamycin (68.3%). A total of 106 (84%) isolates were resistant to three or more antibiotics and 12 multi-drug resistance patterns were observed. The most common pattern (resistance to nalidixic acid, ampicillin, oxacillin, tetracycline and cotrimoxazole) was exhibited by 33 isolates. A total of 40 CoNS isolates were then used to determine the prevalence of the mec A, ica AB and atl E genes. PCR results showed that most isolates 25/40 (62.5%) were positive for the mec A gene. The ica AB and atl E were detected in 32.5% and 25% of the isolates respectively. All isolates which were positive for both the mec A and ica AB genes showed resistance to multiple antibiotics. Conclusion: There is emerging antibiotic resistance in CoNS that cause UTI’s. The occurrence of both the mec A and ica AB genes in CoNS isolates may lead to an increase in antibiotic resistance
Antimicrobial resistance of Escherichia coli isolated from chickens with Colibacillosis in and around Harare, Zimbabwe.
(American Association of Avian Pathologists, 2012-11-14) Saidi, Bamusi; Mafirakureva, Prettimore; Mbanga, Joshua
Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC),can lead to great economic losses in the poultry industry. The aim of this study was to determine the prevalance of antibiotic resistance and antibiotic resistance and antibiotic resistance patterns in APEC in Zimbabwe. From 503 chickens diagnosed with Colibacillosis, 103 E. coli isolates were obtained. Isolation and identification of E. coli were carried out using microscopy and boichemical tests. The disc diffusion method was used to determine antibiotic susceptibility of the isolates to 8 commercial antibiotics. Many isolates exhibited resistance to more than one antibiotic. Antibiogram profiles indicated maximum resistance to tetracycline (100%), bacitracin(100%), and cloxacillin (100%) and a high prevalence of resistance to ampicillin(94.1%0. However; there were high prevalences of sensitivity to ciprofloxacin (100%) and gentamycin (97.1%). The isolates showed moderate rates of sensitivity to chloramphenicol and neomycin.All isolatesin this study showed multidrug resistance because they were all resistant to 3 or more antibiotics. Seven multidrug resistance patterns were observed. The most common pattern (resistance to ampicillin, bacitracin,cloxacillin and tetracycline) was exhibited by 30 isolates.Our findings show that there is emerging drug resistance in APEC associated with colibacillosis in Zimbabwe. The observed high level of multidrug resistance could hamper the treatment of colibacillosis in Zimbabwe.
Antioxidant enzyme profiles in a species of ornamental fish (koi)
(2013-03-11) Naik, Yogeshkumar S.
The aim of this work was to determine whether, and at what levels, antioxidant enzymes are expressed in the various organs of the koi. The activity of the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX), NAD(P)H: :' quinone oxidoreductase (NQOR) and malondialdehyde (MDA) content were determined in tissue homogenates of liver, kidney, pectoral muscle, gills, eggs, blood, heart and intestine. There was a marked variability (up to tenfold difference) in enzyme activity in the various organs, but much less individual variability ( - three fold difference). NQOR activity was highest in eggs (- 5.56(A/min/mg). Catalase activity also found heterogeneously in all organs had its highest activity in the liver ( - 5.02(A/min/mg). GPX (selenium dependent) activity was highest in the liver (5.14(A/min/mg). Thiobarbituric acid reactive substances (MDA) content, a measure of lipid peroxidation was, significantly low in all organs and tissues with an A535/mg of 0.00145(0.0027. The results suggest that antioxidant enzymes are expressed in most organs of the koi and that this species of fish is likely to be protected when exposed to compounds that either undergo redox cycling or that exerl a direct oxidative stress.
“Appropriate Technology for the 21st Century: Technological Innovation to Empower Africa”
(2014-11-25) Dube, Donatus; Parekh, Champaklal T.; Siangwata, Sherpherd; Nyathi, Makhosazana
Low-income earners in Zimbabwe’s rural areas currently depend, to a very large extent, on water from rivers, wells, dams and boreholes. Water from all these sources is contaminated in one form or the other by the anthropogenic as well as natural pollutants and in many cases is unsuitable for human consumption. Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of point – of – use (POU) treatment measures in reducing waterborne diseases. However for poor communities in rural areas of Zimbabwe such interventions have remained largely ineffective due to availability and application challenges, lack of support, resistance due to cultural stigmas and mere ignorance. The aim of this research was to provide a simple POU solution to water quality problems in the rural communities of Zimbabwe. Thermally converted magnetite particle material with nanoporosity was used to construct rudimentary filters for use by villagers. Both laboratory and village scale tests were conducted. Results revealed that filters constructed using nano-porous magnetite material were very effective for microbiological and chemical pollution control in water and can be used successfully and sustainably by poor communities in the rural areas.
Assessing the impact of coal mining activities on soils and terrestrial organisms using land snail Achatina fulica as a bioindicator
(2022) Ndebele, D.
A lack of evaluation of soil quality in Zimbabwe's coal mining regions threatens the soil's ability to support biological productivity. Reports from the Environmental Management Agency of Zimbabwe and the Centre for Natural Resources Governance showed that the river (Deka) that flows through the study area was polluted. Pollutants in the Deka River were possibly emanating from land, but there was no scientific evidence. Hence it was important to evaluate pollution on land in the coal mining area. The biochemical response of the land snail Achatina fulica, exposed to soils collected from the coal mining area, was used to assess soil health. The level of selected heavy metals and polyaromatic hydrocarbon (PAH) levels were determined in soil samples obtained from 7 different sites at a coal mining area over a 2-year period (2018 to 2019). Soils obtained from the coal mining area were used to expose land snails acquired from a comparatively pure environment and acclimated to laboratory settings (for 1 year). The coal mining region's soils were determined to be mildly acidic (pH 5.53). Solubility of some metal elements increases when soils are acidic thus making such metals bioavailable and possibly increasing metal toxicity. The concentrations of heavy metals in soil samples from the coal mining area were significantly higher than in control soils (p < 0.05). The concentrations of zinc and cadmium were found to be above the World Health Organisation maximum permissible limits of 50 and 0.8 mg/kg respectively in the study period. Zinc and cadmium had mean concentrations of 164.40±81.82 and 0.97±0.27 mg/kg respectively. Results of regression analysis indicated that cadmium, lead and zinc were highly bioaccumulated with regression coefficients of 0.90, 0.94 and 0.95 respectively. Metallothionein induction in snail tissue often happen upon exposure of snails to certain metals such as cadmium. The highest levels of metallothioneins were observed in snail tissue exposed to soils with the highest concentration of heavy metal levels. The concentrations of naphthalene, acenaphthene, phenanthrene, anthracene, flouranthene, pyrene, benzo(k)fluoranthene, benzo(a)pyrene and indeno(1,2,3-c,d)pyrene in soils from the thermal power plant area were higher compared to soil from the control site (p < 0.05). High molecular weight (HMW) polycyclic aromatic hydrocarbons were predominant in soil samples from the coal mining area compared to low molecular weight polyaromatic hydrocarbons. High molecular weight polyaromatic hydrocarbons are carcinogenic and benzo(a)pyrene is the most potent. The thermal power plant area had the highest proportion of HMW polyaromatic hydrocarbons thus organisms around the area were likely to be at high risk of cancer and mutations. The sum of 14 polyaromatic hydrocarbons (Σ14 PAHs) at all sites was significantly higher than the 1000 µg/kg allowable in soil by United States Environmental Protection Agency. The ratio of anthracene to the sum of anthracene and phenanthrene was above 1 in soils from the disused coal processing area (Site C), active coal processing area (Site E) and thermal power plant area (Site F). This indicated that polyaromatic hydrocarbons in soils from Site C, E and F mostly emanated from wood, grass and coal combustion. There was a general increase in heavy metal and PAH levels from 2018 to 2019. This was probably because the study area is semi-arid hence leaching and runoff was minimal in soils from the coal mining area. Antioxidant enzyme (superoxide dismutase, catalase, glutathione peroxidase and NAD(P)H quinone reductase) and xenobiotic metabolising enzyme (glutathione S-transferase and ethoxyresorufin O-deethylase) activities were significantly increased in snails exposed to soils from the coal mining area compared to the control soil (p < 0.05). The high antioxidant enzyme activities showed that the snails were adapting to the effects of reactive oxygen species or experiencing oxidative stress. The highest xenobiotic metabolising enzyme activities were observed in snails exposed to soil from the coal tailing and power plant area. Persistent exposure (45 days) of land snails to contaminated soils markedly increased biomarker responses in land snails. Results showed ii that land snails are sensitive bioindicators and may be used to monitor pollution on land. Further more, results showed that combining biomarker measurements and chemical analysis can be a useful approach in evaluating the health of invertebrates in terrestrial ecosystems and the soil quality. The data obtained in this study can be included in soil ecotoxicological data and used in formulating soil quality management frameworks of the area.
An Assessment of the Extent of Bovine Milk Pollution by DDT used in Public Health in Zimbabwe
(Scientia Research Library, 2016) Basopo, N.; Brock, Gerome; Mnkandla, Sanele
Indoor residual spraying of dichlorodiphenyltrichloroethane (DDT) has been widely used in the control of malaria, and has been appreciated for its low cost and high effectiveness. Prolonged use, however, has adverse effects as DDT and its metabolites persist for long in the environment, resulting in human and animal contamination. Contamination in animals such as cattle may result from consuming contaminated water, feed and fodder. The aim of the study was to evaluate the extent of contamination of DDT and its metabolites in cow’s milk from five towns in Zimbabwe. Samples were collected from farms around Bulawayo, Chiredzi, Esigodini, Harare and Mutare with a total of n=24 samples. The pesticide residues were extracted using the quick, easy, cheap, rugged and safe (Quechers®) method and solid phase extraction and analysed using gas chromatography with electron capture detector. Total DDT was detected in all samples at levels higher than the maximum allowable residue limit. Harare and Mutare samples had the highest DDT levels of 0.38 μg/ml and 0.26 μg/ml respectively, as compared with samples from other regions (0.08-0.13 μg/ml). The DDT metabolite residues,1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 1,1-dichloro- 2,2-bis(p-dichlorodiphenyl)ethylene (DDE), were also detected at varying levels in the samples. The results show the presence of DDT and its metabolite contaminants in bovine milk, posing a serious health risk to consumers. Alternatives to DDT may therefore need to be employed in the control of the malaria vector.
Biological and physical features of sisal (Agave sp.) varieties growing in Matebeleland region
(Academy Journals, 2010-10-26) Dube, S.; Chiyaka, Christinah
Five varieties of sisal growing around Matebeleland were studied to determine their biological properties. Morphometric data for Agave deserti are mean of full grown leaf dimensions were, length 64cm, width 9cm, thickness 4mm and fiber yield of 0.0359%. The average fiber length was 50cm and the breaking tensile strain of single ultimate fiber 161.84MPa. For Agave sisalana mean of full grown leaf dimensions were, length 170cm, width 14cm, thickness 5mm and fiber yield of 0.0303%. Average fiber length was 150cm. The breaking tensile strain of single ultimate fiber 88.42MPa. For Agave Americana(variety C) mean of full grown leaf dimensions were, length 215cm, width 22cm, thickness 10cm and fiber yield of 0.0030%. Average fiber length was 200cm. Breaking tensile strain of single ultimate fiber 26.98MPa. For Agave americana (variety D) mean full grown leaf dimensions were, length 200cm, width 22cm, thickness 9mm and fiber yield of 0.0037%. The breaking tensile strain of single ultimate fiber was 54.59MPa. For variety E mean full grown leaf dimensions, length 212cm, width 22cm, thickness 8mm and fiber yield of 0.026%. The terminal spine was absent. The breaking tensile strain of single ultimate fiber 171.16MPa. All the varieties attain full maturity in 5-20 years. Propagation is by bulbils and offsets. Cross sections of the fibres are horse shoe shaped for A, B and E and are lunar shaped for C and D.
Biological oxidants and antioxidants
(2013) Naik, Yogeshkumar S.
The generation of reactive oxygen species, such as the supcroxideanionradical and hydroxyl radical, is known to lead to a variety of pathological conditions. Antioxidants such as vitamins A, C, Eand antioxidant enzymes are known to prevent the deleterious elfects of these toxic radicals. THe role of free radicals in disease may be most familiar to readers of the literature on postischacmic organ reperfusion injury. However, recent studies have shown that these radicals may also play a role in the ageing process, artherosclerosis, carcinogenesisa and even Diabetes mellitus
Biomarkers of Environmental Pollution
(2013-03-14) Naik, Yogeshkumar S.
The threat to our environment due to human activity continues as the need for increased agricultural and industrial output continues. Agrochemicals currently used include pesticides such as organochlorines, organophosphates (OP's), neonicotinoids and pyrethroids. Industrial activity continues to generate an increasing diversity and volume of chemicals, such as PCB's and dioxins, that find their way into our natural and manmade water bodies. Metals such as lead, chromium and cadmium are either mined or are discharged as by-products of human activity. When used safely or disposed of properly these compounds are not always hazardous. However, their improper disposal or use poses a hazard to the health of humans, wildlife and the ecosystem as a whole. They are known to cause a variety of toxic effects such as genetic damage, organ toxicity and several physiological changes such as endocrine disruption. There is.a need to identify such toxic compounds and also to monitor their presence particularly in water bodies of Southern Africa where freshwater is scarce. Some of the methods, currently available to detect such toxins, include the measurement of parameters such as esterase activity (or its inhibition) for OP's, the extent of DNA damage (using the COMET assay) and induction/inhibition of detoxication enzymes (cytochrome P-450, glutathione S-transferase, antioxidant enzymes etc.) and induction of vitellogin synthesis (in fish). However, all these methods are not reliable or sufficiently sensitive. A summary of the data presented in the literature as well as that generated in our own laboratory will be presented.
Carbaryl and Dimethoate Induced Alterations of the Antioxidant Defense System in Two Freshwater Pulmonate Snails Helisoma Duryi and Lymnaea Natalensis
(Scholars Research Library, 2016) Basopo, N.; Naik, Yogeshkumar S.
Organophosphates and carbamates are extensively used to increase the quality and quantity of field crops. These pesticides may indirectly enter water bodies where they affect aquatic organisms. Once absorbed by aquatic organisms the pesticides are metabolised and normal metabolic processes may produce reactive oxygen species that have adverse effects on the aquatic organisms. The effects of exposure to carbaryl and dimethoate pesticides on antioxidant enzymes of two freshwater snail species Helisoma duryi and Lymanea natalensis were evaluated. Groups of snails were exposed to 25 ppb of carbaryl and/or dimethoate for 72 hours. After the exposure duration they were then analysed for their effects on the oxidative defense systems of the snails. Increased thiobarbituric acid reactive substances levels and activities of catalase, superoxide dismutase, glutathione peroxidase and glutathione S-transferase in both snail species were observed, probably as a means of combating oxidative stress due to pesticide poisoning. Increased lipid peroxidation, coupled with altered levels of oxygen free radical scavenging enzymes in snail homogenates are discussed in relation to oxidative stress.
Ceylonocotyle, Bothriophoron, and Calicophoron species Parasitic in some Nigerian Cattle
(Society of Education, 2013-06) Dube, S.; Onyedineke, N.E.; Aisien, M.S.O.
The following genera Ceylonocotyle, Bothriophoron and Calicophoron were recovered from the inner walls of stomachs of cattle slaughtered in abattoirs in the North and South of Nigeria. Some parasites were flattened and diagnostic features taken while some were sectioned in the median saggital plane from where the histology and morphology of the pharynx, genital atrium, acetabulum and testis were analysed for identification. Ceylonocotyle dicranocoelium. Bothriophoron bothriophoron, Calicophoron calicophorum, and Calicophoron microbothrioides were identified. Photomicrographs of the features used in identifications were made and are here presented. Damage to host tissues of the reticulum and rumen was in the majority of cases severe when Ceylonocotyle dicranocoelium was present but the other species did less damage to rumens and reticulum. Parasite loads ranged between 20 and 200 parasites in the infected animals and frequencies of occurrence in cattle were 10% for Ceylonocotyle dicranocoelium, 2 % for B. bothriophoron, 15% for C. calicophorum, and 5 % for C. microbothrides. All the described parasites are being reported in Nigeria for the first time.
Characterization of Fasciola gigantica isolates from cattle from South-western Zimbabwe using RAPD-PCR
(International Organization Of Scientific Research (IOSR)., 2014) Chauke, E.; Dhlamini, Zephaniah; Mbanga, Joshua; Dube, S.
The study sought to characterize Fasciola gigantica isolates from cattle in different localities using RAPD-PCR. Adult flukes morphologically identified as F. gigantica were collected from slaughtered infected animals during meat hygiene inspections. DNA was extracted from single flukes and subjected to RAPD-PCR analysis. In the RAPD-PCR analysis, genomic DNA isolated from the conical anterior end of the worms was amplified by the polymerase chain reaction using 10 random oligonucleotide primers. Depending upon the Fasciola gigantica isolate-primer combination, 1-13 DNA fragments in the range of 75-2000bp were amplified. It was observed that all the 10 primers directing amplification of DNA were of potential interest in the generation of polymorphic DNA. The percentage polymorphic loci ranged from 33.33-100%. Polymorphic bands were scored and used to calculate Nei’s 1978 genetic distance. The genetic distance values ranged between 0.0690 (isolate 5 and 6 from Gwanda and 0.6109 (isolate 6 from Gwanda and isolate 14 from Matopo). The mean Nei’s gene diversity was 0.2839. The study showed the variability of Fasciola gigantica isolates from the same host, using RAPD markers could be applied as a low cost way of identification
Chemical composition and physical characteristics of cowpea haulms as forage for ruminants
(South African Society of Animal Science, 2000) Mokoboki, H.K.; Ayisi, K.K.; Ndlovu, Lindela R
Cowpea ( Vigna unguiculata) is a major grain legume grown by small- scale farmers in the Northern Province of South Africa. The crop is indigenous to Africa and is used extensively in many cropping systems throughout Africa (Eaglesham et al., 1981). Cowpea straws are potential supplementary feed for ruminants in the dry season. Cowpea straws are likely to have higher crude protein than cereal straws and may thus improve digestibility of cereal straws if used together. However, cowpea straws may contain anti-nutritional factors such as tannins and total phenols which affect animal performance. The protein and tannin content of cowpea straws is likely to be affected by variety and growth environment. Straws of varieties adapted to Northern Province have not been evaluated for their content of these constituents. Whilst animal intake and utilisation are the ultimate test of forage suitability, the procedures are unsuitable when large number of forage germ-plasm are to be screened. Chemical and physical characteristics that are known to affect intake and utilisation are often used in such circumstances. The main aim of this research was to determine the effect of variety on physical and chemical characteristics of straws of long season cowpeas and also to determine if haulms of varieties that retain greenness longer will have a better nutritional value than those that dry early.
Combined use of phenyl-bonded phase clean-up and HPLC for the determination of aflatoxins
(Tropical Science, 1996) Siwela, Andrew H.
Phenyl·bonded phase clean-up and HPLC were used to measure aflatoxins in groundnuts, peanut butter, beans, cowpeas and maize meant for human consumption. Of 277 samples, 84% were al or bleow the 20 pp.b. limil. Of 100 animal feed samples, 28% were at or below 5 p.p.b., the proposed limit infeedfor milk-producing animals.

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