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Microbiological status of bulk tank milk and different flavored gomolya cheeses produced by a milk producing and processing plant
73-78Views:581The microbiological quality of milk is important not only for food safety, but it can also influence the quality of dairy products. In this study, our aim was to assess the microbiological status of the bulk milk of a milk-producing farm, and some natural and flavored (garlic, dill, onion) gomolya cheeses made from pasteurized milk produced by their own processing plant. We determined the number of coliform bacteria, Escherichia coli, Staphylococcus aureus, and molds of three milk and eight cheese samples. The tests were conducted between July and September, 2017.
In bulk milk, the mean coliform count was 3.83±0.17 log10 CFU/ml; the mean E. coli count was 1.38±0.14 log10 CFU/ml; the mean mold count was 3.74±1.30 log10 CFU/ml; and the S. aureus count was <1.00 log10 CFU/ml, respectively. The mean coliform count in gomolya cheeses was 3.69±1.00 log10 CFU/g; the mean E. coli count was 2.63±0.58 log10 CFU/g; the mean S. aureus count was 3.69±1.35 log10 CFU/g and the mean mold count was 1.74±0.37 log10 CFU/g. The amount of coliforms detected in different flavored gomolya cheeses were significantly different (P<0.05). More than 10 CFU/g of E. coli was found only in the dill flavored cheeses, and S. aureus was found only in dill (3.66±1.86 log10 CFU/g) and onion (3.71±0.52 log10 CFU/g) flavored gomolya cheeses. Based on the obtained results, it was found that the amount of coliform bacteria and E. coli in bulk milk exceeded the limit set in regulation of the Hungarian Ministry of Health (MoH) 4/1998 (XI. 11.) and the amount of S. aureus was below the limit. For gomolya cheeses, the S. aureus count exceeded the limit. The amount of coliform bacteria remained above the limit in cheeses, except for the garlic flavored gomolya cheese. In cheeses, a larger E. coli count was detected than in the bulk milk, but there is no specific limit for cheeses in the regulation. The mold count exceeded the limit specified in the regulation in cheeses, but a lower value was detected relative to milk.
The results show that, in the case of bulk milk and gomolya cheeses, certain detected quantities exceeded the limit values set forth in regulation of MoH 4/1998 (XI. 11.). The results indicate an inadequate microbiological state of the raw material and the finished products. The reasons for these are due to reduced technological hygiene or the inappropriate handling of raw material and finished products. In this study, we have summarized the results of our preliminary studies, which can provide a basis for further hygiene studies.
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Effects of bioactive plant extracts on immune-related gene expression of common carp (Cyprinus carpio)
49-56Views:740In recent years, intensive fish farming has led to an outbreak of several diseases, and the health status of fish can affect the economy of aquaculture. Since fish health and intestinal health are in correlation, it may also have an impact on immunity. Accordingly, many natural feed additives are being used to improve immune functions. In our study, carotenoids, oligosaccharides, and anthocyanins were applied at 1 m/m% in feed to investigate their effects on cytokines, such as interleukin-1β (IL-1β), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and interferon regulatory factor-1 (IRF-1) in spleen and mid-intestine of 6 months old carp. Gene expression analysis was carried out to examine IL-1β, IL-8, TNF-α, and IRF-1 mRNA levels in fish spleen and mid-intestine. The gene expression level of pro-inflammatory IL-1β decreased in the mid-intestine of carotenoid-fed carp compared to anthocyanin supplemented group, but the effects of the bioactive plant extracts were not observed on the examined cytokines compared to control fish.
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Climatic water balance in Hamelmalo, Eritrea
69-76Views:464Agricultural production is an important sector for peoples to live, but it is highly affected by climate change. To have a good production we need to understand the climatic parameters which adversely affect production. Hamelmalo, which is located in the semi-arid area of Eritrea, is vulnerable to climate change and this is realised in the total production loss. Nevertheless, there is no concrete reference about the climate of the region due to lack of data for a long time. Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water balance (CWB), are imminent effects of climate change. However, changes in the CWB, as a response to changes in P and ET, have not yet been analysed thoroughly enough in many parts of the world, including Eritrea. This study also explores the changes of the CWB in the Hamelmalo region, based on a wide range of climatic data (P, relative air humidity and evaporation pan necessary for computing potential evapotranspiration (PET) with the pan evaporation method) recorded at Hamelmalo from 2015-2019. This analysis shows that the annual cumulative CWB for Hamelmalo is negative in 67% of the years. The dry season without precipitation leads to negative CWB and the change in CWB only starts from the raining or crop season. Based on this recent study, 2015 had the highest PET and lowest P, and this resulted in the lowest CWB in the investigated period. Opposite to this, 2019 had lower PET and highest P, which led to the highest CWB. However, the monthly values of CWB did not correlate with the annual P or ET. On the base of our study, it can be concluded that PET and P were very variable in the investigated years and P was the most influential elements of CWB.
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Dnipropetrovsk National University named after Oles’ Gonchar
9-13Views:177The Dnipropetrovsk National University is a multi-profile educational and scientific complex, where 16 faculties, the faculty of continuing education, the faculty of correspondence and distance education, post-graduate courses, doctorate, three scientific research institutes, 107 sub-faculties (departments) function, where about 1300 teachers including 150 Doctors of Science, professors and about 700 Candidates of Science, associate professors. In Dnipropetrovsk National University 15,000 students study majoring in 64 fields of knowledge and also foreign students and post-graduate students from more than 20 countries of the world study there. The educational and scientific process at the university correspond to the highest levels of the home and world standards.
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The effect of dissolved oxygen on common carp (Cyprinus carpio) and basil (Ocimum basilicum) in the aquaponics system
89-96Views:1060Aquaponics is an integrated system that combines fish farming (aquaculture) and hydroponic plant production. The objective of this study was to examine how the level of dissolved oxygen with or without an air pump affects water quality, fish output and plant growth parameters for common carp (Cyprinus carpio) and basil (Ocimum basilicum).
Ebb – and flood aquaponics systems (with automatic syphon) was used. Two treatments were set in this experiment, one of which was the aquaponics system without air pump (unit I), where water of the plant bed was pumped two directions, one falling back to the fish tank oxygenating the water the other was pumped to the hydroponics unit. The other system (unit II) was designed with an air pump.
In the course of the study, water quality parameters, such as oxygen saturation, dissolved oxygen (DO), electrical conductivity (EC) and nitrite were significantly different (p<0.05). Total basil biomass was higher in unit II. (5367.41 g). The final biomass of common carp were
2829.45 g ± 79.24 and 2980.6 g ± 64.13 g in unit I and unit II respectively. Weight gain (WG) and specific growth rate (SGR) showed no significant differences (p>0.05) between the treatments. -
Evaluation some important microbiological parameters of the carbon cycle in chernozem soils profiles
33-39Views:410Some chemical and microbiological properties of the carbon cycle were investigated in three chernozem soil profiles. The soil profiles originated from a long term fertilization experiment (potato) of the University of Debrecen, Látókép, Kryvyi Rig Botanic Garden (grassland) and a large-scale farm (sunflower) of Ukraine. The results of the organic C-content, total number of bacteria, microscopical fungi, cellulose decomposing bacteria, CO2-production, microbial biomass carbon and saccharase and dehydrogenase activities were compared and evaluated with the help of correlation analyses. Close correlation was found between the organic carbon content and the number of microscopical fungi,, saccharase and dehydrogenase enzymes’ activities, as well as close correlation was found between the dehydrogenase activity and microbial biomass-C and saccharase activity.
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The current status, challenges and prospects of native pig production and large-scale farming in Laos
155-161Views:797This review aimed to investigate the potential native pig development and the trend that large-scale farming may influence native pig production in Laos. The review found that native pigs were estimated to be around 88% of the total pig population in Laos in 2023. Commercial pig farming was found only in the main cities, particularly the central and southern provinces, which increased from 578 in 2019 to 703 farms in 2022 and 737 farms in 2023. Due to the serious economic crisis starting in 2021, many Lao pig producers stopped their businesses, leading to the decline of the commercial pig population by almost 30% in 2023 compared to 2022. The average pork per capita consumption in Laos in 2021 was estimated at about 14.2 kg. Though not as high as the backyard, commercial farms still contribute essentially to the pork supply in Laos (12%), increasing the volume from 87,628 tonnes in 2015 to 137,775 tonnes in 2024. The main native pig producers are small-scale rural farmers who have not yet improved productivity or reproductive performance, and the main purpose of their production is household consumption rather than market orientation. However, farmers, mainly in the main cities, improved them by cross-breeding native pig sows with Duroc boar for better lean meat. The main challenges for native production in Laos include poor farm setup and management, high cost of commercial feed, and poor breeding and genetic management. Therefore, creating awareness of the benefits of setting up a pig farm and management, providing better option strategies for utilising locally available feeds, and providing better strategies on pig breeding could improve native pig production in Laos.
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The impact of cultivar and irrigation on yield, leaf surface temperature and SPAD readings of chili pepper
103-108Views:486Paprika is an extremely popular and widespread plant species in Hungary. Chili peppers belongs to paprika and it can be consumed fresh or processed. The production of peppers began with the cultivation and control of some parameters for good results of paprika production. The aim of this article is to compare the water supply of four chili pepper hybrids ("Habanero", "Hetényi Parázs", "Unikal" and "Unijol") by means of investigation on open field and to examine how different temperatures and water stress factors influence the yield of chili peppers. The experiment area consisted of four different hybrids in three different irrigation treatments (control, deficit- and regular irrigation). The chlorophyll content was estimated with SPAD and the leaf surface temperature with Raytek MX4 TD. Our research concluded that deficit irrigation produced the highest yields for all cultivars and the lowest yields for the highest water supply.
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Testing of Various Solvents for the Preparation of Lipid Samples for Use in Thin Layer Chromatography
49-50Views:172We analyzed the muscular tissue of 6 sheep. Lipid extraction was performed using the Handson and Olley method. TLC separation was performed using 4 separation systems and the best separation method was determined. Visualization was done using a mixture copper acetate and phosphoric acid, at 150 oC.
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The influence of the fertilizing system on the petroleum residues biodegradation on a preluvosoil under control polluted
251-254Views:222The paper presents the partial results of researches regarding the agrochemical melioration of soils under control polluted by petroleum residues that took place at the Agricultural and Research and Development Station in Oradea, Bihor County.
The experimental device was made out of 1 m2 microparcels, spread out in subdivided parcels, in four repetitions, having tree factors: A - the pollution by crude oil from Suplacu de Barcău, B – the mineral fertilization, and C – the organic fertilization.
The experience was set out on a preluvosoil în the year 1993 and the soil was cultivated with millet in the first 3 years and with spring wheat in the last 7 years of research.
The researches carried out in Oradea had the objective of establishing the effects of the fertilizing system on the petroleum residue biodegradation on a preluvosoil under control polluted with crude oil from Suplacu de Barcău, Bihor County. -
The potential use of Pediococcus spp. probiotic in aquaculture: A review
99-106Views:610Aquaculture production has significantly increased over the previous few decades. However, antibiotics have been implemented regularly and extensively to overcome outbreaks of pathogens in aquaculture to cover the human needs for animal protein, leading to the appearance of resistant strains that may cause serious damages in the environment and also human health. In the last few years, the implementation of probiotics as an alternative technique to antibiotics use in fish production has achieved promising results in aquaculture due to their beneficial impact on fish health and growth performance. Among different types of probiotics, the Pediococcus spp. bacteria stand out as a promising probiotic for their beneficial impact to aquaculture. Thus, the current study has been conducted to give an overview about the interactions between Pediococcus spp. and aquaculture. In addition, this review highlights the role of Pediococcus spp in promoting growth performance, improving feed conversion ratios and the intestinal architecture, enhancing the immune response and inhibiting fish pathogens, thereby preventing or at least reducing the use of antibiotics. Practical use of Pediococcus spp. probiotic in aquaculture as feed additives through selected case studies is also considered.
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Modern methods to determine vitamin E in foods and feeds
53-58Views:266Highly specific and sensitive, the proposed fluorometric method for determining α-tocopherol is robust and fairly fast. It
has been tested in parallel with a conventional thin layer chromatographic method on foods and feeds. The only necessary
cleanup is the usual saponification. The unsaponificable fraction can be extracted with ethyl ether or, preferably, with
Extrelut columns. Reagents and their solvents are added to the isooctane solution before each successive reaction and are
then eliminated by partition with water. The α-tocopherol (α-T) derivative always remains in isooctane. The first step is
nitrosation and elimination of tocopherols and tocotrienols other than α-isomers. α-T is then oxidized to α-tocored (α-TR)
with a mixture of sulfuric acid, ferric chloride, and iodine bromide. Α-TR is then condensed to a new reagent: 4,5-dimethylo-
phenylenediamine. The phenazine formed is strongly fluorescent. Iodine and bromine add to the double bonds of α-
tocotrienol present and quench the fluorescence of its phenazine. -
Yield components of hairy vetch (Vicia villosa Roth.) in different sowing technologies on acidic sandy soil
83-88Views:849Nearly a quarter of the agricultural utilized area of our country is made up of sandy soils. Sandy soils are poor in nutrients, and, therefore, the effectiveness of farming is basically determined by the method of maintaining soil fertility and the fertilization practice.
The hairy vetch called Vicia villosa Roth (Sandy Roth.), also known as a sand pioneer, plays a significant role in the exploitation of sandy soils. Its cultivation was started in Hungary in the late 1800s. It is primarily used as green fodder, most recently as a green manure and as a soil protection plant. The lupine is grown mainly as a supportive plant, which was previously rye, and today it is triticale. The ratio of the two plants to each other and the spatial location of plants depend on the method of sowing.
The aim of our work was to present the yields of some of the grain grown in different sowing methods and some of its crops.
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Effect of anthocyanin-rich Hungarian tart cherry extract on blood antioxidant status in C57BL/6J mice
335-341Views:477In this study male C57BL/6J (B6) mice were used to determine the possible effects of our Hungarian tart cherry extract in a chronic obesity mouse model on antioxidant capacity.
The control group received standard mouse chow, the high fat control group was switched to high fat diet and tap water supplemented with 5% sucrose. The high fat+anthocyanin group received the high fat and sucrose diet, but dissolved in the drinking water they received anthocyanin-rich tart cherry extract. After six weeks, the antioxidant capacity and SOD activity were measured. Antioxidant capacity was decreased with a significant elevation of SOD activity. The tart cherry extract made a significant enhancement in antioxidant capacity and SOD activity. Our results show that chronic anthocyanin intake has a potential to enhance redox status associated with obesity.
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The effect of water-stress on the mineral nutrition of fruit plantations
187-192Views:379Besides agro-techniques the climatic conditions play an important role in agricultural production. Weather extremes are
significant hazards to many horticultural regions all over the word. It has a profound influence on the growth, development and yields of a
crop, incidence of pests and diseases, water needs and fertilizer requirements in terms of differences in nutrient mobilization due to water
stresses. Nowadays, the weather extremes cause more and more problems and significant hazards to many horticultural regions in Hungary.
The aim of this study is to explore the problems of nutrient uptake followed from climatic anomalies and response it. In this study
we focus on water supply problems (water-stress).
Reviewing the effects and nutrient disorders caused by climatic anomalies, the following statements can be taken:
· Nutrient demand of trees can be supplied only under even worse conditions.
· The most effective weapon against damage of climatic anomalies is preventative action.
· Proper choice of cultivars, species and cultivation should provide further possibilities to avoid and moderate the effects of
climatic anomalies.
· Fruit growing technologies especially nutrition should be corrected and adjusted to the climatic events as modifier factors.
· The role of foliar spraying, mulching and fertigation/irrigation is increasing continuously.
· Urgent task of the near future is to correct and adjust the tested technologies of fruit growing according to these climatic events as
modifier factors.
Optimal nutrient supply of trees decreases the sensitivity for unexpected climatic events. To solve these problems supplementary, foliar
fertilization is recommended, which adjusted to phonological phases of trees. Moreover, mulching is regarded as an excellent water saving
method. -
Change of antioxidant compounds of spices during drying
77-81Views:445Spices and herbs have been used by humanity for thousands of years, so they are very important plants.
In this study, the change of dry matter content and antioxidant compounds of eight spices (basil, thyme, rosemary, mint, parsley, lemongrass, chives, coriander) have been examined the raw plants and in plants preserved by three different drying methods (an oven in 50–60°C; drying at room temperature; lyophilisation between -40 and -50°C, under pressure), because we wanted to see the change of the parameters.
The water content of raw plants was very high, i.e. the dry matter content was very low. By the application of the three drying methods nearly 100% of the water has left the plants, with the exception of the lyophilized basil and rosemary.
Based on the results related to the original material, lyophilized has proved to be the best treatment for the preservation of antioxidant compounds, however air drying also showed high results for some spices.
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The importance of chickpea (Cicer arietinum L.) and its cultivation in Hungary: A review
71-75Views:255Climate change today is no longer a question for the future. Climate change impacts not only human populations but also plant species, which are increasingly exposed to its negative effects. The increasing number of days of drought, the lack of precipitation and its unfavorable distribution are observed each year, which require adaptation. Chickpea (Cicer arietinum L.) is a drought-tolerant species characterized by deep root system that enables it to withstand prolonged periods without precipitation. Additionally, it is a thermophilic crop and tolerates moderate increases in average temperature." There is no great tradition of its cultivation and use in Hungary, but it has been cultivated by the Iregszemcse Research Institute since the 1970s. In addition to the positive aspects of its cultivation, it also has good nutritional values, outperforming in some parameters the beans (Phaseolus vulgaris L.) and peas (Pisum sativum L.) what are popular in Hungary. Its high protein and crude fibre content allows it to be used not only for human consumption but also for animal feed. The aim of this review is to describe the importance of chickpea and to identify the advantages and disadvantages of its cultivation.
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Analysis of sweet corn nutritional values using multivariate statistical methods
103-108Views:656Processing large amounts of data provided by automated analytical equipment requires carefulness. Most mathematical and statistical methods have strict application conditions. Most of these methods are based on eigenvalue calculations and require variables to be correlated in groups. If this condition is not met, the most popular multivariate methods cannot be used. The best procedure for such testing is the Kaiser-Meyer-Olkin test for Sampling Adequacy. Two databases were examined using the KMO test. One of them resulted from the sweet corn measured in the scone of the study, while the other from the 1979 book of János Sváb. For both databases, MSA (measures sampling adequacy) was well below the critical value, thus they are not suitable e.g. for principal component analysis. In both databases, the values of the partial correlation coefficients were much higher than Pearson’s correlation coefficients. Often the signs of partial coefficients did not match the signs of linear correlation coefficients. One of the main reasons for this is that the correlation between the variables is non-linear. Another reason is that control variables have a non-linear effect on a given variable. In such cases, classical methods should be disregarded and expert models better suited to the problem should be chosen in order to analyse the correlation system.
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The effect of crop rotation and fertilization on wheat and maize in the pedoclimatic conditions of the Banat Plain
14-18Views:178The simplification of the plant cultures range and the yields in the last 10-15 years brings into the actuality the role of crop rotation and
of fertilization on the yield level and stability for wheat and maize even on the soils with a high natural fertility. The results of the researches
performed between the years 2006 – 2009 on a cambic low gleyed chernozem from the Banat Plain showed that the wheat cultivated in
monoculture gives productions with 59-81% lower than that cultivated in crop rotation with other plants during 2-4 years. In maize, the yield
obtained in monoculture is situated behind that obtained in crop rotation with 11-21%. The most favorable crop rotations for wheat were
rape-wheat in a 4 years rotation and soybean-wheat in simple rotation of 2 years. In maize, the most favorable was the 2 years rotation
(wheat-maize). The mineral fertilization was very efficient both in wheat (11-36%) and maize (9-31%). The organic fertilization with manure
was very efficient for maize, the yields being superior with a mean value by 34% for a 60 t/ha dose and with 16% for 30t/ha. The fertilization
compensates the negative effect expressed by the monocultivation only in a small measure -
Comparison of alveohraph and extensigraph properties of winter wheat samples
27-30Views:453The rheological properties of dough are determined by the amount and proportion of gliadin and glutenin proteins. Extensibility and resistance to the extension of doughs which can be measured using the extensigraph or alveograph allow good assesment of the baking behavior under realistic conditions. In our study, we compared the extensigraph and alveograph parameters of 87 flour samples. The results showed that the alveograph parameters were different from the extensigraph parameters. The classification of wheat varieties was different, and the order of varieties, as well. The alveograph properties were affected by other factors than the extensigraph properties, except the W value. The two rheological tests did not give similar results, therefor neither test are replaceable.
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Investigating the above-ground biomass values of sweet potatoes (Ipomoea batatas)
35-39Views:393The role of sweet potato tubers in human nutrition is not new. The above-ground biomass of sweet potatoes is not used for nutritional purposes in most countries, but it has a high biological value. Therefore, the aim of the present study is to investigate the production of press fibre from above ground biomass by wet fractionation. Two sweet potato varieties (purple- and white-fleshed sweet potato) and two types of irrigation system were used: bubbling water flow system (BWS) and continuous water flow system (CWS). Glucan, xylan, arabinan were analysed by HPLC and elemental content was measured by ICP-OES. Our results show that the total carbohydrate content in the pressed fibre of the leaf blades (27.64–29.88 %w/w) is lower than in the stem with petiole (51.14–57.36 %w/w). No significant difference in glucan, xylan and arabinan content was observed in the leaf blade. In the stem with petiole, significant differences were observed for xylan and arabinan contents. For elemental content, generally higher values were measured in the leaf blade than in the stem with petiole. This information may be relevant for the selection of the appropriate variety and treatment, even for the production of functional food.
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Essential oil extraction from herbs and their use in the food industry
59-74Views:588Essential oil extraction of wild caraway and thyme was performed using a classical (HD) and microwave hydro-distillation (MWHD) and a laboratory supercritical fluid extraction (SFE) with a carbon dioxide as solvent. Our experiments demonstrated that the extraction yield of the essential oil performed in same conditions was influenced by the location of growth area; the maximum extraction yield of 10 ml 100 g-1 caraway was obtained from dried seeds collected from Csíkmadaras. This quantity far exceeded the yield of the Újtusnád samples. In the case of wild caraway (Carum carvi L.), the extraction method influenced thecomposition of the essential oil (carvone/limonene ratio), the highest limonene content being achieved by classical hydro-distillation. In the case of thyme, this effect was not detected, the thymol/carvacrol ratio was independent from the given extraction method. The obtained thyme essential oil possesses high antimicrobial activity demonstrated by agar diffusion test. The thyme extract provides a good protection against microorganisms collected on the surface of fresh vegetables following bacterial stains: Citrobacter portucalensis, Pseudomonas hunanensis, Pseudomonas baetica, Pseudomonas parafulva, Bacillus mojavensis and Enterobacter cloacae. Protective effect was also detected on the vegetable surface of by chitosan-based edible film coating during a 6-day-long storage period at a temperature of 4 °C. The caraway essential oil used as soft cheese seasoning with a direct, dilution-free method, proved to be unsuitable because the uneven distribution and confer a strong, unpleasant taste to the product in comparison with the ground wild caraway seed-dressed cheese.
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Examination of the efficacy of different fungicides against Macrophomina phaseolina and Sclerotinia sclerotiorum in laboratory conditions
21-24Views:586Macrophomina phaseolina and Sclerotinia sclerotiorum are two significant fungal pathogens of sunflower. M. phaseolina causes charcoal rot and ashy stem blight in several important crop species. Sclerotinia sclerotiorum causes white mold disease which can occur as middle stalk rot, head rot and premature plant death. Due to the wide host range of the two pathogens and their survival structures, crop rotation cannot provide sufficient protection against them. In our experiment, we selected two fungicides, Mirage and Prosaro, which are widely used in practice, and we tested their efficacy against the two pathogens. The efficiency of these fungicides was tested at a concentration of 10; 20; 50; 100 and 500 ppm. The Prosaro totally inhibited the mycelial growth of both pathogens at a concentration of 50 ppm, 100 ppm and 500 ppm. The Mirage caused total mycelial growth inhibition in all treatments against both pathogens.
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The presence of the undertaken social and economic role in the university's strategy-making
93-96Views:257It is vital to examine the strategic plans and leadership insights of the university, the faculties, the departments and the institutions in the research of the „third mission” of the universities. Because of the undertaken social-economic role in the region it is indispensable to know the turbulently changing environment (hazards – opportunities), to map the competencies available in the university (strengths – weaknesses) and to recognize the relations between the external and internal environment. It is an important factor to define the strategic directions of the departments, examining them in direction dimension (pro-active – adaptive) and in role dimension (top-down – bottom-up). The main objective of this research is to recognize the formal and informal strategic visions of the institutes and departments in the Centre for Agricultural and Applied Economic Sciences of the University of Debrecen, and to examine how these visions are related to the university's role in the regional innovation system.
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Preliminary results of the combined production of duckweed Spirodela polyrhiza and common carp (Cyprinus carpio) in an aquaponic system
83-89Views:423As a result of population growth, increasin amount of food is needed, and agriculture is under an increasing burden to meet these needs. Traditional agriculture is often attacked due to its environmental impact. We must find alternative, environmentally friendly ways to produce more food. Aquaponics is a closed system in which we can produce both fish and plants at the same time. Duckweed species are small, aquatic, floating plants belonging to angiosperms. It can potentially be an alternative protein source, due to its high protein content, good amino acid supply, and rapid growth. Under suitable conditions, it doubles its weight in 2–4 days, and can reach a yield of 30 t ha-1 year-1in dry matter. It forms a carpet on top of the water and can be found in slow-moving or still waters. Since they are resistant to a wide range of nutrient concentrations, they are also suitable for cleaning wastewater (such as eutrophicated lakes, sewage reservoirs, liquid manure storage). Fish feed is the primary nutrient source for aquaponic systems, which usually contains fishmeal. If duckweed can be used as an alternative for fishmeal in the feed, it could improve the sustainability of the aquaponic and aquaculture systems. In this study, the aim was to develop an optimal harvesting protocol for duckweed Spirodela polyrhiza under aquaponic conditions. In a four weeks experiments, four harvesting protocols were set up, a control where only biomass measurements were made, a 25% group where 25% of the biomass at the time of measurement was harvested, and a 50% and a 75% group where at the time of measurement 50% and 75% of the biomass was harvested. Three replicates were used per treatment. We weighed the biomass every week and removed the amount corresponding to the group. Based on the preliminary results, it can be said that more biomass was obtained in the groups with the 25% harvesting protocol and the control group.