خيارات البحث
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Mitochondrial DNA variation of indigenous goat populations from Peste-des-petits-ruminants outbreak in South Kivu, Democratic Republic of the Congo
2018
Bwihangane, B.A. | Gitao, G.C. | Bebora, L.C. | Tarekegn, M.G. | Nicholas, S. | Bacigale, Samy B. | Svitek, Nicholas
This study was conducted to investigate the genetic diversity at d-loop of mitochondrial DNA and establish the possible maternal lineages of indigenous goat breeds in Democratic Republic of Congo (DRCongo). Phylogenetic relationships among and within 111 goats from three indigenous populations from a peste-des-petits ruminants outbreak in South Kivu, Eastern of Democratic Republic of the Congo and 22 goats sequences from the gene bank were analysed using mitochondrial control region sequences (d-loop region). The results show that a total of 120 segregating sites, 56 haplotypes and 124 mutations were found in a 1220-bp sequence. The mean haplotype diversity and nucleotide diversity were 0.971±0.007 and 0.011±0.002, respectively with the overall number of nucleotide differences of 10.73. The phylogenetic analysis showed that all goat sequences were clustered into two haplogroups (A and B), of which haplogroup A was the commonest. The global analysis of molecular variance (AMOVA), incorporating all the three populations independent of any hierarchical clustering, indicated that 83.22% of the total genetic variation present in studied goats was explained by genetic differences between individuals (pv= 0.327), 11.18% among groups (pv=0.000*) and only 5.60% of the variation was attributed to genetic differences between populations (pv=0.003*). These results conclude that there are high levels of intrapopulation diversity in Mwenga-Shabunda, Fizi and Kalehe goats and the weak phylogeographic structuring, thus, suggested that there existed strong gene flow among goat populations probably caused by extensive trans-border movement of goats in the past
اظهر المزيد [+] اقل [-]In vitro methane production and ruminal fermentation parameters of tropical grasses and grass-legume associations commonly used for cattle feeding in the tropics
2022
Uribe, Xiomara Gaviria | Bolívar Vergara, Diana M. | Chirinda, Ngonidzashe | Molina Botero, Isabel Cristina | Mazabel, Johanna | Rosales, Rolando Barahona | Arango, Jacobo
In vitro study was carried out to measure methane (CH4) production and ruminal fermentation parameters of tropical forages either commonly used and with a potential for inclusion in Colombian livestock systems. The forages evaluated wereUrochloa hybrid cv. Cayman, Leucaena leucocephala, Leucaena diversifolia, Megathyrsus maximus cv. Mombaza, Urochloa brizantha cv. Toledo, Canavalia brasiliensis,Urochloa decumbens, Tithonia diversifolia and Dichantium aristatum. which were incubated using the in vitro gas technique for 96 h. Treatments with higher neutral detergent fiber (NDF) and crude protein (PC) contents had higher gas production, dry matter (DM) degradability and the highest CH4 production (ml/g DMd) at 24 hours. Methane at 24 hours of incubation varied between 4.69 and 8.10 ml and increased by 43% on average at 48 hours. In all treatments, the highest proportion of volatile fatty acid (VFAs) corresponded to acetate, which was more than 50% of the total VFAs produced. Treatments with Urochloa hybrid cv. Cayman and their associations with Leucaena diversifolia had the lowest CH4 production values at 24 h. Similarly, treatments with Cayman grass, its associations with Leucaena and Toledo grass alone showed the highest DM degradability values. In conclusion, the inclusion of Leucaena and Tithonia diversifolia on a diet based on forage grass (Cayman or Toledo) had a positive effect on nutrient content and degradability and the group of treatments that included Cayman grass and its associations had lower CH4 production values and higher degradability than the rest of the treatments.
اظهر المزيد [+] اقل [-]From taboo to commodity: history and current situation of cavy culture in the Democratic Republic of the Congo
2014
Maass, Brigitte L. | Metre, TK | Tsongo, F | Mugisho, AB | Kampemba, FM | Ayagirwe, R.B.B. | Azine, PC | Bindelle, J. | Chiuri, Wanjiku L.
Development of winter wheat blotches depending on fungicide treatment schemes and nitrogen rates
2020
Svarta, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Bimsteine, G., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Stanka, T., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Daugavina, L., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Pluduma-Paunina, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
One of the factors affecting winter wheat grain yields are leaf blotches. The two-factorial trial was conducted in the Research and Study farm ‘Pēterlauki’ in 2017/2018 and 2018/2019 (Latvia). Four nitrogen rates and five fungicide treatment schemes were used. The aim was to clarify the impact of leaf blotches on the winter wheat yield. In winter wheat plots, the tan spot (caused by Pyrenophora tritici-repentis) dominated but also Septoria leaf blotch (caused by Zymoseptoria tritici) was found. The severity of leaf blotches in winter wheat was low in both years due to dry and warm weather. The development of leaf blotches was influenced by fungicide application schemes, but not by nitrogen fertilizer rate. The total disease impact during the vegetation period was estimated by calculation the area under the disease progress curve (AUDPC). AUDPC for both diseases were significantly higher in the variant without fungicides (F0) and in the variant, where half of dose of fungicides at the growth stage (GS) 55–59 (F1) was used. The using of full dose of fungicide at the GS 55–59 (F2) as well as using of fungicides two (F3) or three (F4) times in growing season significantly decreased the values of AUDPC for both diseases, but differences among AUDPC values in mentioned three variants were not significant. Results showed that the nitrogen fertilization significantly increased the average per both years grain yield until the nitrogen rate N180. Fungicide treatment schemes had no significant effect on the average grain yield.
اظهر المزيد [+] اقل [-]Occurrence of genetic lineages of Puccinia striiformis in Latvia
2020
Feodorova-Fedotova, L., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Inst. of Soil and Plant Sciences;Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Research Inst. of Plant Protection | Bankina, B., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Inst. of Soil and Plant Sciences
Puccinia striiformis is a biotrophic pathogen able to cause broad scale epidemics in wheat growing regions. P. striiformis is genetically highly variable pathogen. New, aggressive genetic lineages, adapted to warm temperatures have been observed in the last decades worldwide. The study aimed to ascertain the structure of genetic lineages of P. striiformis in Latvia. Forty one wheat leaf samples with yellow rust symptoms were collected in 2017–2019. Fenotyping and genotyping methods were used for identification of genetic lineages in Global Rust Reference Center, Denmark. Assessments of leaf diseases on winter wheat differentials – ‘Ambition’, ‘Mariboss’, ‘Moro’, ‘Compair’, ‘Rendezvous’, ‘Spalding Prolific’ and local variety ’Fredis’ were made during the research. Five genetic lineages of P. striiformis – PstS4, PstS7, PstS10, PstS13 and PstS14 were found. 56% from the samples belonged to PstS14, 17.1% PstS10, 12.2% PstS4 and PstS7, 2.4% PstS13. Genetic lineages identified from Latvian wheat samples are found in the biggest cereal growing regions in Europe and are able to cause epidemics on wheat. Genetic lineages of P. striiformis from Latvian samples have not been identified before. All differential varieties were infected with P. striiformis in 2017, ‘Ambition’ and ‘Moro’ in 2018, no infection was observed on differentials in 2019 despite the presence of P. striiformis on winter wheat variety ‘Fredis’. The identification of genetic lineages of P. striiformis on wheat in Latvia is necessary to continue.
اظهر المزيد [+] اقل [-]Open geo-spatial data for sustainable forest management: Lithuanian case
2020
Tiskute-Memgaudiene, D., Vytautas Magnus Univ., Kaunas (Lithuania) | Mozgeris, G., Vytautas Magnus Univ., Kaunas (Lithuania) | Gaizutis, A., Forest Owners Association of Lithuania, Vilnius (Lithuania);Vilnius University (Lithuania)
In Lithuania, forests are managed by Lithuanian State Forest Enterprise, municipalities, ministries, etc. and private forest owners. About 50% of all forest land is State importance, privately owned forests cover 40% of forest land, and about 10% of forest land belongs to forests reserved for restitution. Forest management of private ownership force many challenges, because private forest owners are people, who have purchased or received the property after restitution, and often lacks knowledge about forest resources, its dynamics and sustainable forest management. As remote sensing is a valuable source for forest monitoring, because it provides periodic data on forest resource and condition status, these methods are gaining increased attention worldwide. In this context, more scientific efforts are made at developing remote sensing derived geo-spatial data services for sustainable forest management through a web service platform, which would integrate geo-information into daily decision making processes and operation for private forest owners. This article presents a review of privately owned forests’ statistics, questionnaire-based survey about GIS usage and demand for forest owners in Lithuania and links available sources of open geo-spatial data useful for sustainable forest management.
اظهر المزيد [+] اقل [-]Carbon stock in litter and organic soil in drained and naturally wet forest lands in Latvia
2020
Butlers, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The aim of the study is to evaluate carbon stock in litter and organic forest soils in Latvia as well as to characterize accumulation of carbon in litter in afforested lands. The study is providing empirically valid information about soil and litter carbon changes for the National greenhouse gas (GHG) inventory by using data from National forest inventory (NFI), forest soil monitoring demonstration project BioSoil and other studies. The study proves significance of organic forest soil carbon pool in Latvia and demonstrates necessity to extend NFI incorporated forest soil monitoring program to improve data on soil density in wet organic soils, as well as to integrate data characterizing water regime in forests. The acquired data also proves that the conservative approach of calculation of carbon stock changes in litter in afforested lands applied in the Latvia’s National GHG inventory avoids overestimation of CO2 removals. The data on litter carbon stock collected in this study is sufficient to estimate total carbon stock for stands dominated by most common tree species and long term impact of changes of species composition. Measurements of organic soil and litter thickness should be continued by NFI and integrated with more detailed soil monitoring to increase accuracy of carbon stock estimates and gather data necessary for verification of modelling data, particularly in afforested lands and due to change of dominant species.
اظهر المزيد [+] اقل [-]Evaluation of productivity and costs of Malwa forest machine in sanitary fellings in Latvia
2020
Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Kaleja, S., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Ariko, S., Belarusian State Technological Univ., Minsk (Belarus)
The topicality of the study is determined by the increasing demand for sanitary felling services currently mainly provided by manual work. Harvesting using hand-held motor instruments is a physically hard work whose costs are increasing rapidly, but labour availability is declining. In sanitary cuttings, additional complications are caused by the use of conventional machinery in harvesting, which necessitates the creation of wide (4 m) technological corridors and significantly increases the proportion of damaged remaining trees in a stand (according to past studies, a set of middle-class forest machines in thinning of spruce stands results in 4–5% of damaged trees, but in pine stands – in approximately twice less damaged trees than in spruce stands). The compact class forest machines in thinnings result in mechanical damage to not more than 1% of remaining trees. During field trials in sanitary felling 9329 trees were felled. The average productivity, working in one shift, is 5.35 m**3 hE−1 with average stands 10 cm. The cost of harvester’s productive hour is 92 € but of a forwarder it is 78. The compact class forwarder creates significantly smaller impact on the soil by reducing ruts depth and soil compaction, which is especially important in sanitary fellings and extraction of seed trees in regenerated areas.
اظهر المزيد [+] اقل [-]Pyrolysis and acid hydrolysis of lignocellulosic biomass as a tool for monosaccharide obtaining
2020
Godina, D., Latvian State Inst. of Wood Chemistry, Riga (Latvia);University of Latvia, Riga (Latvia) | Pomilovskis, R., Latvian State Inst. of Wood Chemistry, Riga (Latvia) | Iljina, N., Latvian State Inst. of Wood Chemistry, Riga (Latvia));University of Latvia, Riga (Latvia) | Meile, K., Latvian State Inst. of Wood Chemistry, Riga (Latvia
Due to the ever increasing demand for energy resources, more and more attention is being paid to renewable energy resources. One such potential resource is lignocellulosic biomass that can be treated to acquire a carbohydrate rich substrate for further use in producing biofuels such as bioethanol or biobutanol. In this study, birch (Betula pendula) chips were used in fast pyrolysis to acquire bio-oil. This bio-oil was further hydrolyzed in pressurized reactor Parr 4554 to produce a carbohydrate rich feedstock. Hydrolysis conditions were optimized. Several conditions − three different temperatures (111, 121, 131 °C) and four different sulfuric acid concentrations (0.05, 0.1, 0.2, 0.5 M) were tested. The optimal conditions were 121 °C with 0.2 M sulfuric acid as a catalyst that allowed to acquire a solution with the total glucose concentration being 6.6% that can be further used as a feedstock for biofuel acquiring.
اظهر المزيد [+] اقل [-]The comparison of the spray-drying and freeze-drying techniques for camel milk: a review
2020
Tastemirova, U., Almaty Technological Univ. (Kazakhstan) | Ciprovica, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Shingisov, A., M. Auezov South-Kazakhstan State Univ., Shymkent (Kazakhstan)
The aim of the present study was to analyse and compare camel milk powder quality and functional properties produced with spray-drying and freeze-drying techniques. Freeze-drying is recognized as an advanced method for the production of high-quality dried products, but it has been a costly process for production of camel milk powder. Spray-drying and freeze-drying of camel’s milk demonstrated that the nutritional characteristics of this product basically remained unchanged compared to fresh milk. The differences were found analysing flowability, solubility and hygroscopicity of camel milk powder samples obtained with freeze-drying and spray-drying technique. Analysed quality indices of camel milk demonstrated that spray-drying has lower impact on camel milk powder physical properties in comparison with freeze-drying.
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