Browsing by Author "Mugerwa, Swidiq"
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Item Comparison of the efficacy of crude methanolic extracts of Cassia occidentalis and Euphorbia hirta with levamisole-HCL against gastrointestinal nematodes of economic importance to goat production in Uganda(Tropical animal health and production, 2019) Nsereko, Godfrey; Emudong, Patrick; Omujal, Joseph; Acai, James; Kungu, Joseph M.; Kabi, Fredrick; Mugerwa, Swidiq; Bugeza, JamesNatural compounds from medicinal plants provide safe and sustainable alternatives to synthetic anthelmintics. In this study, we assessed in vitro and in vivo anthelmintic activity of Cassia occidentalis (NH-A) and Euphorbia hirta (NH-B) and compared it with levamisole-HCl. The shoots of NH-A and whole plant of NH-B were used to prepare extracts using 70% methanol which were used in the in vitro and in vivo assays. In vitro assays of crude methanolic extracts (CMEs) of NH-A and NH-B on larvae of mixed gastrointestinal nematodes (GINs) of goats revealed mortalities of 95.7%(at 100 mg ml−1) and 98.1%(at 50 mgml−1) 24 h postexposure. In vivo assays of NH-A administered orally at doses of 100, 300, 900, and 2700 mg kg−1 bwt revealed dose- and time-dependent anthelmintic effects in goats experimentally infected with mixed species of GINs. NH-B exhibited similar properties when administered at doses of 50, 100, 200, and 400 mg kg−1 bwt. Both NH-A (900 mg kg−1 bwt) and levamisole (7.5 mg kg−1 bwt) achieved a 100% reduction in fecal egg count per gram (EPG) on day 21 and day 14 respectively posttreatment. NH-B (400 mg kg−1 bwt) achieved 93.1% and 86.1% reduction in fecal EPG 7 and 14 days postexposure respectively compared with 88.2% and 82.3% reduction with levamisole-HCl 7 and 14 days postexposure. Our results show that extracts of both plants can disrupt helminth lifecycles by suppressing the egg-laying capacity in adult worms but also kill their infective larvae. Future studies should aim at establishing synergies or antagonisms between the two plant extracts and further development for control of helminths in goats.Item The Correlation between Subolesin-Reactive Epitopes and Vaccine Efficacy(Vaccines, 2022) Contreras, Marinela; Kasaija, Paul D.; Kabi, Fredrick; Mugerwa, Swidiq; De la Fuente, JoséVaccination is an environmentally-friendly alternative for tick control. The tick antigen Subolesin (SUB) has shown protection in vaccines for the control of multiple tick species in cattle. Additionally, recent approaches in quantum vaccinomics have predicted SUB-protective epitopes and the peptide sequences involved in protein–protein interactions in this tick antigen. Therefore, the identification of B-cell–reactive epitopes by epitope mapping using a SUB peptide array could be essential as a novel strategy for vaccine development. Subolesin can be used as a model to evaluate the effectiveness of these approaches for the identification of protective epitopes related to vaccine protection and efficacy. In this study, the mapping of B-cell linear epitopes of SUB from three different tick species common in Uganda (Rhipicephalus appendiculatus, R. decoloratus, and Amblyomma variegatum) was conducted using serum samples from two cattle breeds immunized with SUB-based vaccines. The results showed that in cattle immunized with SUB from R. appendiculatus (SUBra) all the reactive peptides (Z-score > 2) recognized by IgG were also significant (Z-ratio > 1.96) when compared to the control group. Additionally, some of the reactive peptides recognized by IgG from the control group were also recognized in SUB cocktail–immunized groups. As a significant result, cattle groups that showed the highest vaccine efficacy were Bos indicus immunized with a SUB cocktail (92%), and crossbred cattle were immunized with SUBra (90%) against R. appendiculatus ticks; the IgG from these groups recognized overlapping epitopes from the peptide SPTGLSPGLSPVRDQPLFTFRQVGLICERMMKERESQIRDEYDHVLSAKLAEQYDTFVKFTYDQKRFEGATPSYLS (Z-ratio > 1.96), which partially corresponded to a Q38 peptide and the SUB protein interaction domain. These identified epitopes could be related to the protection and efficacy of the SUB-based vaccines, and new chimeras containing these protective epitopes could be designed using this new approach.Item Genetic Diversity and Population Structure of Brachiaria (syn. Urochloa) Ecotypes from Uganda(MDPI AG, 2020-08) Namazzi, Clementine; Sserumaga, Julius Pyton; Mugerwa, Swidiq; Kyalo, Martina; Mutai, Collins; Mwesigwa, Robert; Djikeng, Appolinaire; Ghimire, SitaBrachiaria (syn. Urochloa) grass is an important tropical forage of African origin that supports millions of livestock and wildlife in the tropics. Overgrazing, conversion of grasslands for crop production and non-agricultural uses, and the introduction of improved forages have threatened the natural diversity of Brachiaria grass in Uganda. This study established a national collection of Brachiaria ecotypes in Uganda and analyzed them for genetic diversity and population structure using 24 simple sequence repeats (SSR) markers. These markers had a high discriminating ability with an average polymorphism information content (PIC) of 0.89 and detected 584 alleles in 99 ecotypes. Analysis of molecular variance revealed a high within populations variance (98%) indicating a high gene exchange or low genetic differentiation (PhiPT = 00.016) among the ecotype populations. The Bayesian model based clustering algorithm showed three allelic pools in Ugandan ecotypes. The principal component analysis (PCA) of ecotypes, and Neighbor-joining (NJ) tree of ecotypes and six commercial cultivars showed three main groups with variable membership coefficients. About 95% of ecotype pairs had Rogers’ genetic distance above 0.75, suggesting most of them were distantly related. This study confirms the high value of these ecotypes in Brachiaria grass conservation and improvement programs in Uganda and elsewhere.Item Genome-wide diversity and structure variation among lablab [Lablab purpureus (L.) Sweet] accessions and their implication in a Forage breeding program(Genetic Resources and Crop Evolution, 2021) Sserumaga, Julius Pyton; Kayondo, Siraj Ismail; Kigozi, Abasi; Kiggundu, Muhammad; Namazzi, Clementine; Walusimbi, Kato; Bugeza, James; Molly, Allen; Mugerwa, SwidiqMost orphan crops have not been fully sequenced, hence we rely on genome sequences of related species to align markers to different chromosomes. This hinders their utilisation in plant population improvement programs. Utilising the advances in the science of sequencing technologies, the population structure, relatedness, and genetic diversity among accessions can be assessed quickly for better exploitation in forage breeding programs. Using DArTseq technology, we studied the genetic and structural variation in 65 Lablab purpureus (L.) Sweet conserved gene-bank accessions using 9320 DArTseqbased SNPs and 15,719 SilicoDart markers. These markers had a low discriminating ability with mean polymorphic information content (P.I.C.) of 0.14 with DArTseq-based SNPs and 0.13 with SilicoDart markers. However, the markers had a high mean call rate of 73% with DArTseq-based SNPs and 97% with SilicoDart markers. Analysis of molecular variance revealed a high within populations variance (99.4%), indicating a high gene exchange or low genetic differentiation (PhiPT = 0.0057) among the populations. Structure analysis showed three allelic pools in variable clusters of DK = 3 and 6. Phylogenetic tree of lablab accessions showed three main groups with variable membership coefficients. Most pairs of accessions (40.3%) had genetic distances between 0.10 and 0.15 for SilicoDart markers, while for DArTseq-based SNPs, (46.5%) had genetic distances between 0.20 and 0.25. Phylogenetic clustering and minimum spanning analysis divided the 65 accessions into three groups, irrespective of their origin. For the first time, this study produced high-density markers with good genom coverage. The utilisation of these accessions in a forage program will base on the information from molecular-based grouping. The outcomes uncovered the presence of noteworthy measure of variety in Uganda, CIAT and ILRI accessions, thus demonstrating an opportunity for further marker-trait-association studies.Item Inspiring Anti-Tick Vaccine Research, Development and Deployment in Tropical Africa for the Control of Cattle Ticks: Review and Insights(Vaccines, 2022) Kasaija, Paul D.; Kirunda, Halid; Nanteza, Ann; Kabi, Fredrick; Mugerwa, Swidiq; Fuente, José de laTicks are worldwide ectoparasites to humans and animals, and are associated with numerous health and economic effects. Threatening over 80% of the global cattle population, tick and tick-borne diseases (TTBDs) particularly constrain livestock production in the East, Central and Southern Africa. This, therefore, makes their control critical to the sustainability of the animal industry in the region. Since ticks are developing resistance against acaricides, anti-tick vaccines (ATVs) have been proposed as an environmentally friendly control alternative. Whereas they have been used in Latin America and Australia to reduce tick populations, pathogenic infections and number of acaricide treatments, commercially registered ATVs have not been adopted in tropical Africa for tick control. This is majorly due to their limited protection against economically important tick species of Africa and lack of research. Recent advances in various omics technologies and reverse vaccinology have enabled the identification of many candidate anti-tick antigens (ATAs), and are likely to usher in the next generation of vaccines, for which Africa should prepare to embrace. Herein, we highlight some scientific principles and approaches that have been used to identify ATAs, outline characteristics of a desirable ATA for vaccine design and propose the need for African governments to investment in ATV research to develop vaccines relevant to local tick species (personalized vaccines). We have also discussed the prospect of incorporating anti-tick vaccines into the integrated TTBDs control strategies in the sub-Saharan Africa, citing the case of Uganda.Item Monitoring the Subolesin Vaccine Field Trial for Safer Control of Cattle Ticks Amidst Increasing Acaricide Resistance in Uganda(Vaccines, 2022) Kabi, Fredrick; Dhikusooka, Moses; Matovu, Moses; Mugerwa, Swidiq; Kasaija, Paul; Emudong, Patrick; Kirunda, Halid; Contreras, Marinela; Gortazar, Christian; De la Fuente, JoseA collaboration program was established between the group of Health and Biotechnology (SaBio) of the IREC Institute of Game and Wildlife Research (CSIC-UCLM-JCCM, Spain) and the National Agricultural Research Organization of Uganda (NARO) for the development of vaccines for the control of cattle ticks in Uganda. Controlled pen trials identified a tick protective antigen, Rhipicephalus appendiculatus Subolesin, and a cross-species-effective vaccine formulation. As the next step, a controlled vaccine field trial has been approved by Ugandan state regulatory authorities, the Uganda National Council for Science and Technology (UNCST) and the National Drug Authority (NDA), to evaluate the efficacy and effectiveness of the vaccine formulation for the control of cattle tick infestations under field conditions. The results of this trial may lead to the approval of the vaccine for application in Uganda to improve cattle health and production while reducing the use of acaricides.Item Optimizing bio-physical conditions and pre-treatment options for breaking lignin barrier of maize stover feed using white rot fungi(Animal Nutrition, 2016) Atuhaire, Andrew M.; Kabi, Fred; Okello, Samuel; Mugerwa, Swidiq; Ebong, CyprianThe greatest limitation to utilization of maize stover by ruminants as a feed is the high concentration of lignin, which limits fibre digestibility.However, ruminants can effectively utilize maize stover if its nutritive value is improved using white rot fungal species. This study was designed to determine optimal biophysical conditions for mycelial growth and select the most ideal fungal species and pre-treatment options for improving nutritive value of maize stover. Four popular edible Pleurotus fungal species (viz. Pleurotus florida, Pleurotus ostreatus, Pleurotus sajor caju and Pleurotus pulmonarius) were subjected to varying temperatures, pH levels, hydrogen peroxide (H2O2) concentration and illumination to establish the extent ofmycelial growth rate. Inclusion of H2O2was used to determine optimal levels for preservation and prevention of contamination from other indigenous microbiota. Effects of pre-treatment options on chemical composition and nutritive value of maize stover were also examined. Mycelial growth rate of Pleurotus species on potato dextrose agar (PDA) varied (P < 0.05) with temperature, pH level and H2O2 concentration following a quadratic trend. Optimal temperature, pH and H2O2 concentration for mycelial growth on PDA were 25 C, 5 and 0.01 mL/L, respectively. Under the different bio-physical conditions, P. sajor caju had the highest mycelia density and growth rate. Chemical composition of solid-state fermented maize stover differed (P < 0.05) among the Pleurotus species. Maize stover fermented with P. sajor caju had the highest crude protein (CP) of 86.6 g/kg DM, in-vitro dry matter digestibility (IVDMD) of 731 g/ kg DM, in-vitro organic matter digestibility (IVOMD) of 670.4 g/kg DM and metabolizable energy (ME) of 10.0 MJ/kg DM but with the lowest lignin (sa) of 50 g/kg DM. At 25 C, P. sajor caju had the highestmycelial growth rate on PDA and highest lignin (sa) breakdown in the maize stover substrate. It was, therefore, selected as the most ideal fungal species for improving nutritive value of maize stover. Pre-treatment of maize stover with Lactobacillus plantarum and molasses under anaerobic condition for 7 days before inoculation with P. sajor caju resulted into a substratewith the highest (P < 0.05) CP (96.6 g/kg DM), IVDMD (752.3 g/kg DM), IVOMD (687.2 g/kg DM) and ME (10.2 MJ/kg DM). However, neutral detergent fiber exclusive of residual ash (NDFom) and lignin (sa) fractions decreased (P < 0.05) as a result of subjecting maize stover to pre-treatment with L. plantarum and molasses prior to fermentation with P. sajor caju.Item Prioritization of Agro-industrial By-products for Improved Productivity on Smallholder Dairy Farms in the Lake Victoria Crescent, Uganda(Frontiers in Science, 2014) Atuhaire, Andrew M.; Mugerwa, Swidiq; Okello, Samuel; Lapenga, Kenneth; Kabi, Fred; Lukwago, GeorgeLivestock feed fluctuations in quality and quantity is a major constraint to dairy cattle production in Uganda, particularly, in smallholder dairy cattle production. Studies on prioritizing agro-industrial by-products in dairy cattle feeding are central to formulation of sustainable feed management strategies. This study was thus conducted to investigate farmers’ knowledge of agro-industrial by-product management as dairy cattle feed to build logical ideology required in development of appropriate feed management strategies. Focus group discussion and individual interviews were conducted in Lake Victoria Crescent agro-ecological zone to capture information on farmers’ knowledge of the factors enhancing agro-industrial by-products utilization, temporal and spatial variability, and limitations to utilization in smallholder dairy farming system. Chi-square test at p<0.01, df = 3 showed a significant difference among farmers rankings of utilization and factors limiting utilization (p<0.01, df = 4) of agro-industrial by-products across all the study districts. There was no significant difference (p>0.05) in spatial and temporal variability of agro-industrial by-products. The study provided basic information about farmers’ knowledge on importance of agro-industrial by-products that could aid the development of sustainable and socially acceptable dairy cattle feed management strategies.Item Prioritization of Crop Residues for Improving Productivity on Smallholder Dairy Farming Households in the Lake Victoria Crescent, Uganda(Open Journal of Animal Sciences, 2014) Mwebaze Atuhaire, Andrew; Mugerwa, Swidiq; Okello, Samuel; Okello Lapenga, Kenneth; Kabi, Fred; Kabirizi, Jolly MaryPoor nutrition has been identified as a major constraint to productivity in smallholder dairy farming households in Uganda, particularly in Lake Victoria Crescent Agro-ecological Zone (LVZ). Clarification on nutritional potential of crop residues is central to formulation of sustainable dairy cattle nutrition strategies. Data were collected from 126 randomly selected respondents using structured and semi-structured questionnaires. Farmers’ responses on crop residues utilization, handling, limitations, spatial and temporal variability were collected. Kruskal-Wallis test showed significant differences on utilization of available crop residues (X2 = 50.4, df = 4, p = 0.0001) among farmer’s rankings. It was established that maize stovers were major crop residues utilized and inadequate knowledge to process crop residues was ranked as a major limitation. The study provided basic information on the importance of crop residues. Further research studies should focus on improving the nutritive value of maize stover.Item The Role of Bentonite Clays in Aflatoxin-Decontamination, Assimilation and Metabolism in Commercial Poultry(Biomedical Journal of Scientific & Technical Research, 2022) Nviiri, Geofrey; Kigozi, Abasi R.; Turyagyenda, Laban; Mugerwa, SwidiqMost of the poultry feeds in Uganda are highly contaminated with aflatoxins (65-1000 ppb) far beyond the acceptable limits of 20 ppb. Due to the dependence on such feeds, commercial poultry in Uganda is highly susceptible to aflatoxicosis, which is reflected in the reduced growth and health performance. As a result, severe losses due to poor poultry productive performance and health defects are common due to the consumption of aflatoxin-contaminated feeds. The purpose of this review, therefore, is to bring to attention the dangers of aflatoxicosis in the Uganda poultry industry, human-related consequences, and the possible mitigation opportunities. As a consequence of reviewing 105 research articles, it is observed that consumption of aflatoxin-contaminated feeds poses vast aflatoxicosis-related production deficits as well as contamination of poultry products. The resultant aflatoxicosis, which is associated with compromised feed conversion efficiency, reduced vaccine efficacy, and histological organ deterioration, becomes a key production challenge. Such challenges not only increase the cost of production but also the risk of losing birds due to highly infectious diseases like Newcastle and infectious bursal disease, which are known to cause up to 100% chicken mortality. For that reason, poultry productivity and aflatoxicosis-associated risks in human populations cannot be improved without embracing aflatoxin-decontamination technologies from the feeds. The use of high affinity non-nutritive adsorbents like bentonite clays is one of the most promising decontamination techniques that can be used to combat the toxic effects of aflatoxins on feed utilization, organ health, and toxin carry-over in poultry products. Moreover, according to several authors, feed intake (DMI), weight gain, and organ health are key in assessing broiler response to aflatoxin decontamination. Whereas Uganda is well endowed with a diversity of such clays in the Albertine region, there is inconsistent and insufficient information about the inclusion levels of the different bentonite clay in poultry diets. In addition, none of the previous studies has compared commercial aflatoxin binders with other bentonite clays as well as established the optimum inclusion levels of Albertine bentonite clays. Yet, beyond certain optima, bentonite clays are hypothesized to hinder nutrient utilization alongside the negative effects of excess calcium in the case of calcium bentonite. Furthermore, due to the transfer of aflatoxins and their metabolites to poultry edible products and their effect on human health.Item Vaccination with Recombinant Subolesin Antigens Provides Cross-Tick Species Protection in Bos indicus and Crossbred Cattle in Uganda(Vaccines, 2020) Kasaija, Paul D.; Contreras, Marinela; Kabi, Fredrick; Mugerwa, Swidiq; Fuente, José de laCattle tick infestations and transmitted pathogens a ect animal health, production and welfare with an impact on cattle industry in tropical and subtropical countries. Anti-tick vaccines constitute an e ective and sustainable alternative to the traditional methods for the control of tick infestations. Subolesin (SUB)-based vaccines have shown e cacy for the control of multiple tick species, but several factors a ect the development of new and more e ective vaccines for the control of tick infestations. To address this challenge, herein we used a regional and host/tick species driven approach for vaccine design and implementation. The objective of the study was to develop SUB-based vaccines for the control of the most important tick species (Rhipicephalus appendiculatus, R. decoloratus and Amblyomma variegatum) a ecting production of common cattle breeds (Bos indicus and B. indicus x B. taurus crossbred) in Uganda. In this way, we addressed the development of anti-tick vaccines as an intervention to prevent the economic losses caused by ticks and tick-borne diseases in the cattle industry in Uganda. The results showed the possibility of using SUB antigens for the control of multiple tick species in B. indicus and crossbred cattle and suggested the use of R. appendiculatus SUB to continue research on vaccine design and formulation for the control of cattle ticks in Uganda. Future directions would include quantum vaccinology approaches based on the characterization of the SUB protective epitopes, modeling of the vaccine E under Ugandan ecological and epidemiological conditions and optimization of vaccine formulation including the possibility of oral administration.