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Results 2881 to 2910 of 4099:

Ruminal degradability of dry matter and neutral detergent fibre of grasses

F. Jančík, V. Koukolová, P. Homolka

Czech J. Anim. Sci., 2010, 55(9):359-371 | DOI: 10.17221/211/2009-CJAS

A study was conducted (I) to determine rumen degradability (in sacco) of dry matter (DM) and neutral detergent fibre (NDF) of the most important grass species grown in the Czech Republic, (II) to compare grass species (n = 5) according to calculated degradation parameters, and (III) to establish prediction equations for degradation parameters from chemical composition. Forty samples of the most important grass species (Dactylis glomerata, Phleum pratense, Lolium perenne, Festuca arundinacea, Felina hybrid) were harvested in 2004 and 2005 and analyzed for chemical composition, and DM and NDF in sacco degradability. Results from the in sacco method were used to calculate DM and NDF degradation parameters. Linear and stepwise multiple regression analyses were used to develop prediction equations for DM and NDF degradation parameters from nutrient concentrations. The highest DM and NDF degradation parameters were found for Lolium perenne. DM and NDF rumen degradation parameters were successfully predicted from chemical composition, with a single predictor adequate for most parameters. For all parameters R2-values increased with addition of more predictors into regression equations. Effective degradability (ED) of DM calculated at a rumen outflow rate (k) of 0.05 h-1 was the best predicted by NDF (R2 = 0.878), and ED of NDF at k = 0.02 h-1 by crude protein (CP) (R2 = 0.653).

Dual infection of rabies virus and Babesia canis in a dog: a case report

J. Habus, Z. Stritof, V. Stevanovic, K. Martinkovic, Z. Milas, V. Staresina, N. Turk

Vet Med - Czech, 2010, 55(6):294-296 | DOI: 10.17221/2989-VETMED

A young adult labrador was presented for evaluation of hind leg weakness, depression, vomiting and severe icterus of skin and mucosa. Physical examination and laboratory findings suggested cerebral babesiosis. Unresponsiveness to treatment and unknown vaccinal status aroused suspicion of rabies which was confirmed post mortem.

The influence of Picea abies on herb vegetation in forest plant communities of the Veporské vrchy Mts.

F. Máliš, J. Vladovič, V. Čaboun, A. Vodálová

J. For. Sci., 2010, 56(2):58-67 | DOI: 10.17221/39/2009-JFS

Natural mixed beech-fir forests were quite widely replaced by spruce dominated stands in Slovakia. Given the demands on the assessment of the forest status as well as on stopping the biodiversity loss it is required to evaluate the influence of Picea abies (L.) Karst. on the species composition. In a case study from the Veporské vrchy Mts. natural beech dominated forests were compared to stands with different spruce proportion. Within three groups of relevés with no, less and more than a half proportion of Picea abies the species diversity and Ellenberg indicator values were compared. The response of particular species to the proportion of Picea abies was evaluated by partial relation in direct gradient analysis. The increasing spruce proportion causes particularly higher occurrence of acidophytes and a decrease in nitrophytes. Species with the highest positive response to spruce are mostly shallow-rooted or characteristic of natural spruce forests. Greater richness along with the highest diversity was found in mixed stands with less than a half proportion of Picea abies. The most significant difference in species composition was between natural and spruce dominated stands. However the proportion of Picea abies does not reduce the species diversity in general, it causes significant changes in the species composition. As the results show, to avoid the negative effect and loss of phytodiversity it is required not to grow spruce dominated stands out of the natural occurrence of Picea abies.

Soybean yield and yield component distribution across the main axis in response to light enrichment and shading under different densities

B. Liu, X.B. Liu, C. Wang, Y.S. Li, J. Jin, S.J. Herbert

Plant Soil Environ., 2010, 56(8):384-392 | DOI: 10.17221/189/2009-PSE

A 2-year field experiment was conducted under light enrichment and shading conditions to examine the responses of seed yield and yield components distribution across main axis in soybean. The results showed that the maximum increase in seed yield per plant by light enrichment occurred at 27 plants/m2, while the most significant reduction in seed yield per plant by shading occurred at 54 plants/m2. Light enrichment beginning at early flowering stage decreased seed size on average by 7% while shading increased seed size on average by 9% over densities and cultivars, resulting in a fewer extent compensation in seed yield decrement. Responses to light enrichment and shading occurred proportionately across the main axis node positions despite the differences in the time (15-20 days) of development of yield components between the high and low node positions. Variation intensity of seed size of three soybeans was dissimilar as a result of changes in the environment during the reproductive period. The small-seed cultivar had the greatest stability in single seed size across the main axis, followed by moderate-seed cultivar, while large-seed cultivar was the least stable. Although maximum seed size may be determined by genetic potential in soybean plants, our results suggested that seed size can still be modified by environmental conditions, and the impact can be expressed through some internal control moderating the final size of most seeds in main stem and in all pods. It indicates that, through redistributing the available resources across main stem to components, soybean plants showed the mechanism, in an attempt to maintain or improve yield in a constantly changing environment.

In situ conservation of fruit landraces

F. Paprštein, J. Sedlák, V. Holubec

Czech J. Genet. Plant Breed., 2010, 46(10):S57-S59 | DOI: 10.17221/695-CJGPB

In situ conservation is considered as conservation of wild biota in the natural habitat (locality). The authors extend the term to cultivated fruit species naturalised in the landscape, such as occasional spontaneous seedlings, and planted material such as old solitary trees among fields, old groves, avenues (country lanes), wind-breaks, and abandoned remnants of orchards. In situ conservation is also used to mark unique materials during collecting expeditions, before they will be taken as ex situ or proclaimed as permanent in situ. Important landraces found within 12 regions of the Czech Republic were registered, evaluated, and in situ localised by Global Positioning System (GPS). The following accessions were marked for in-situ conservation: apple (401), sweet cherry (263), pear (91), plum (42), sour cherry (27), and berry fruits (18).

Influence of the EU enlargement on the agrarian foreign trade development in member states

M. Svatoš, L. Smutka

Agric. Econ. - Czech, 2009, 55(5):233-249 | DOI: 10.17221/34/2009-AGRICECON

The paper analyses the development of agrarian foreign trade of the EC/EU states in the period 1961-2006. The aim of the analysis is to evaluate the influence of the EC/EU member base enlargement on the development of the value and territorial structure of the Community agrarian trade. Additionally, the paper analyses the impacts of the accession of the particular countries on their own and the total agrarian trade of the Community with the aim to clarify the development trends which preceded the accession to the EC/EU and which subsequently appear after the accession of the given state to the Community. Development trends recorded in the case of all joined countries in the period 1973-2006 are compared and in the final part of the paper, the impacts of the enlargement of the EC/EU on the development of internal (intra) and external (extra) trade are summarised.

Corn yield response to partial rootzone drying and deficit irrigation strategies applied with drip system

A. Yazar, F. Gökçel, M.S. Sezen

Plant Soil Environ., 2009, 55(11):494-503 | DOI: 10.17221/96/2009-PSE

This paper evaluates the effect of partial root zone drying (PRD) and deficit irrigation (DI) strategies on yield and water use efficiency of the drip-irrigated corn on clay soils under the Mediterranean climatic conditions in Southern Turkey. Four deficit (PRD-100; PRD-75; PRD-50; and DI-50) and one full irrigation (FI) strategies based on cumulative evaporation (E pan) from class A pan at 7-day interval were studied. Full (FI) and deficit irrigation (DI-50) treatments received 100 and 50% of Epan, respectively. PRD-100, PRD-75 and PRD-50 received 100, 75 and 50% Epan value, respectively. The highest water use was observed in FI as 677 mm, the lowest was found in PRD-50 as 375 mm. PRD-100 and DI-50 resulted in similar water use (438 and 445 mm). The maximum grain yield was obtained from the FI as 10.40 t/ha, while DI-50 and PRD-100 resulted in similar grain yields of 7.72 and 7.74 t/ha, respectively. There was a significant difference among the treatments with respect to grain yields (P < 0.01). The highest water use efficiency (WUE) was found in PRD-100 as 1.77 kg/m3, and the lowest one was found in FI as 1.54 kg/m3.

Effects of lead on seedling growth of spesia populnea

M. Kabir, M.Z. Iqbal, M. Shafiq, Z.R. Farooqi

Plant Soil Environ., 2010, 56(4):194-199 | DOI: 10.17221/147/2009-PSE

The effects of lead on root, shoot and seedling length, leaf area, number of leaves, plant circumference, seedling dry weight, root/shoot and leaf area ratios of Thespesia populnea L. were determined in greenhouse under natural environmental conditions with and without phytotoxic metal ions at 5, 10, 15, 20, and 25 µmol/l. Lead treatments have a strong influence on the growth and development of T. populnea by reducing significantly (P < 0.05) all the above parameters. Lead treatment at 5-25 µmol/l produced significant (P < 0.05) effects on seedling and root length, plant circumference and seedling dry weight of T. populnea, while lead treatment at 10-25 µmol/l produced significant (P < 0.05) effects on shoot length, number of leaves and leaf area as compared to control. Tolerance in T. populnea seedling at 25 µmol/l of lead treatment was lowest as compared to all other treatments.

The Balkan collections 1941-1942 of Hans Stubbe in the Gatersleben Gene Bank

H. Knüpffer

Czech J. Genet. Plant Breed., 2010, 46(10):S27-S33 | DOI: 10.17221/2675-CJGPB

The German Federal Gene Bank at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben comprises ca. 148 000 accessions of crop plants and their wild relatives. Among these, material from Albania and Greece is represented with ca. 1100 and more than 2700 accessions, respectively. IPK's collection of Albanian germplasm is the world's largest collection, while IPK's Greek germplasm collection is the third largest holding of Greek crops and their wild relatives. The largest part of this material (ca. 200 and 1600 accessions from Albania and Greece, respectively) originates from two collecting expeditions carried out by Hans Stubbe, the founder of the Institute for Cultivated Plant Research, and other German collectors during the Second World War, in 1941 (ca. 700 accessions) and 1942 (ca. 1100 accessions). Stubbe's expeditions are described with respect to the regions visited, species collected, plus a comparison between the original collections and their present state in the IPK Gene Bank is provided. A formal scientific report about the results of these expeditions had never been published before. The material from these expeditions can be freely requested from the IPK Gene Bank, after signing a Material Transfer Agreement.

In vitro effects of essential oils on potential pathogens and beneficial members of the normal microbiota

A.C. Ouwehand, K. Tiihonen, H. Kettunen, S. Peuranen, H. Schulze, N. Rautonen

Vet Med - Czech, 2010, 55(2):71-78 | DOI: 10.17221/152/2009-VETMED

The use of antimicrobial growth promoters has been banned in the EU. This has created an interest in alternative strategies to prevent an imbalance in the intestinal microbiota and the potential development of intestinal disorders in livestock. Essential oils (EOs) have been known to exhibit antimicrobial activity against specific microbial species and could therefore be considered one such alternative in controlling the intestinal microbial population. Under anaerobic conditions, the tested Clostridium perfringens strains were found to be sensitive (P < 0.05) to carvacrol, cinnamaldehyde, citral, limonene, thymol, particularly at the higher concentration tested (500 mg/l) and to oregano oil, rosemary oil and thyme oil. Streptococcus epidermis was sensitive (P < 0.05) to most EO's tested, also mainly at the higher concentration. The tested Salmonella serovars were found to be sensitive (P < 0.05) only to high (500 mg/l) concentrations of the tested EOs. Escherichia coli was sensitive (P < 0.05) to most of the tested EOs, also at lower concentrations (5 and 50 mg/l). Bifidobacterium longum, Bifidobacterium breve and Lactobacillus reuteri were less sensitive (P < 0.05) to most of the tested EOs, while Bifidobacterium animalis ssp. lactis and L. fermentum were relatively sensitive also at lower concentrations (5 and 50 mg/l), although growth reduction by EOs of these bacterial species was less then with the antimicrobial growth promoter avilamycin. With the exception of Salmonella and E. coli, all tested microbes were sensitive to avilamycin. Selected EOs seem to have the advantage of inhibiting the growth of potential pathogens while only moderately influencing beneficial members of the intestinal microbiota. This difference in sensitivity may strengthen the microbiota and contribute to improved animal health.

Effects of an aerobic training program on oxidative stress biomarkers in bulls

B.M. Escribano, I. Tunez, F. Requena, M.D. Rubio, R. De Miguel, P. Montilla, P. Tovar, E.I. Aguera

Vet Med - Czech, 2010, 55(9):422-428 | DOI: 10.17221/2979-VETMED

The aim of this study was to evaluate the effect of aerobic training (16 weeks - T1 and 24 weeks - T2) on oxidative stress biomarkers. To this end, GSH, GSH-peroxidase (GSH-Px) and catalase (CAT) activity were analysed in plasma. Nine bulls (3-4 years), were included in this work. The exercise training protocol was performed in a track ("taurodromo") three days per week for 24 weeks and consisted of 400 m warming up, 1200 m to 4-5 m/s, two minutes' resting, 1200 m to 4-5 m/s and, finally, 400 m walking. The results reflected that GSH-Px activity was higher at T1 (6.18 ± 0.45) than at baseline (T0; 2.31 ± 0.08) while the GSH level (2.98 ± 0.37) was lower vs. T0 (14.59 ± 3.40). Moreover, there were significant increases in GSH-Px (18.23 ± 1.36) and CAT (2.52 ± 0.04) activities and the recovery of basal values in GSH (11.75 ± 2.84) in T2. In conclusion, the type of training carried out in this study involved two well-defined stages: (i) a period of perturbation, followed by (ii) adaptation. The former stage was characterised by the induction of oxidative stress manifested as a decrease in the GSH, and the latter (T2) by the recovery of this non-enzymatic antioxidant.

Rodent-caused damage to forest trees from the viewpoint of forestry practice

J. Kamler, K. Turek, M. Homolka, E. Bukor

J. For. Sci., 2010, 56(6):265-270 | DOI: 10.17221/70/2009-JFS

Small mammals cause serious damage to forests but there is only little knowledge of their ecology and possibilities of plantation protection. The objective of our study was to collect information on the damage caused by rodents to plantations of forest tree species. Data were obtained from a survey conducted in 2008 that was aimed at damage caused by small mammals. Questionnaires were sent mostly to foresters engaged in the Lesy CR state enterprise. We obtained usable data from 316 foresters. The response rate was 81%. It was confirmed that rodents cause significant damage all over the Czech Republic and that the occurrence of damage cannot be easily predicted with certainty as significant damage may appear perhaps in a small part of the threatened plantations where the key conditions for small mammals have been fulfilled. The main factors which affected probability of damage include: presence of a woody species attractive to rodents; suitable structure of ground vegetation enabling the pest species to breed sufficiently during the vegetation period; and also long-lasting snow cover. The current approach of forestry practice to damage by small mammals is considerably passive and we are missing an alert system of threat to stands and a methodology of dealing with problematic situations. Most of the foresters are uninterested in small mammals and many have only very smattering knowledge of the dangerousness of individual species and their ecological requirements. The use of rodenticides is expensive and the most effective and economic measure to lower damage by small mammals is to support forest management favouring natural regeneration of forest stands.

The scenario of microfinance in Latin America against the international financial crisis

Gutierrez Ramirez Enver DALAN, Karel SRNEC

Agric. Econ. - Czech, 2010, 56(12):583-590 | DOI: 10.17221/49/2010-AGRICECON

Latin America has very good conditions for microfinance; the macroeconomic growth which Latin America had shown in the recent years created favourable conditions for the microfinance institutions' favorable conditions and its development. Profitability of the microfinance sector presents an attractive market for the financial institutions which already have a have strong position in the market. The purpose of this work is to focus on the current situation and performance of the microfinance sector while identifying some of the reasons that affect the microfinance institutions in this region. The work also provides a view on the microfinance industry development to get a better description of the sector. The microfinance institutions are earning an undeniable importance in the process of the regional development and represent an important factor in the alleviation of poverty and insecurity for large segments of the population. The work is based on information from relevant sources that allow us to identify the current status of microfinance in Latin America, especially in these times when the crisis affects also the region's economic dynamism.

Communities of oribatid mites and heavy metal accumulation in oribatid species in agricultural soils in Egypt impacted by waste water

Hamdy Mahmoud EL-SHARABASY, Ahmed IBRAHIM

Plant Protect. Sci., 2010, 46(4):159-170 | DOI: 10.17221/31/2010-PPS

The continued use of waste water for irrigation of agricultural fields in Egypt may lead to accumulation of heavy metals in soils and adverse effects on soil-living communities. We investigated responses of oribatid communities to heavy metal contamination in mango plantations irrigated by the Ismailia canal in the Suez region. Mean concentrations of heavy metals determined in irrigation water were considerably above the recommended levels. Concentrations of metals in agricultural soil were however below the permissible levels. A comparison with concentrations of a typical uncontaminated soil in this area revealed that the Ismailia water canal used for irrigation of agricultural land has elevated levels of heavy metals. The results of our ecological survey showed that the abundance and structure of the soil oribatid communities were not influenced by levels of heavy metals in the soil. We also showed that the diversity index can be a valuable tool for assessing the possible impact of pollutants on different species of oribatid mites. The oribatid species appeared to be accumulating different amounts of heavy metals when characterised by their bioconcentration factors. Most species were poor zinc accumulators. The accumulation of heavy metals in the body of oribatids was not strictly determined by their body size or by the trophic level. In conclusion, our study showed that mango plantations impacted by waste water from the Ismailia canal are accumulating heavy metals in their soils above the background concentrations, but ecological effects on soil-living communities are not apparent yet.

Effect of heavy metals on soil respiration during decomposition of sugarcane (Saccharum officinarum L.) trash in different soils

R.K. Verma, D.V. Yadav, C.P. Singh, A. Suman, A. Gaur

Plant Soil Environ., 2010, 56(2):76-81 | DOI: 10.17221/1773-PSE

An experiment was conducted to study the effect of heavy metals (Cd, Cr and Pb), soil texture (sandy, loam and clay) and incubation periods (7, 15, 30, 60, 90 and 120 days) on soil respiration (CO2 evolution) during sugarcane trash decomposition in laboratory conditions of the Indian Institute of Sugarcane Research, Lucknow, India. Surface soils (0-15 cm) were collected from agricultural fields and crop residue of sugarcane trash (Saccharum officinarum L.) was taken in the institute farm. Crop residue (10 t/ha) and heavy metals (10, 50, 100, 1000 μg/g) were mixed and incubated at 30°C ± 2°C in an incubator. The rate of soil respiration (CO2 evolution) decreased with increasing heavy metals concentration. During the 120 days, the toxicity decreased but still remained significant. Maximum soil respiration was recorded at 7 days of incubation period; further, it decreased with increasing incubation period. The highest drop of soil respiration rate was caused by addition of 1000 μg/g Cd, Cr and Pb levels. Clay soils evolved maximum CO2 followed by loam and sandy soil.

Analysis of soil degradation in the Czech Republic: GIS approachOriginal Paper

Bořivoj ŠARAPATKA, Marek BEDNÁŘ, Pavel NOVÁK

Soil & Water Res., 2010, 5(3):108-112 | DOI: 10.17221/487-SWR

In our work, we have evaluated the available data on the individual types of soil damage, which has been processed in the Czech Republic in recent decades. The individual types of degradation (water erosion, wind erosion, soil compaction, extreme soils (clay soils), loss of organic matter, acidification, dryness impact, and intoxication) were classified in one of three groups: physical degradation, desertification and chemical degradation. Each type of degradation was assigned a specific weight reflecting the importance of this kind of soil degradation. The maps of individual areas of degradation were processed by overlay and assigning weighting techniques in ArcView Spatial Analyst GIS environment to create the final maps for each class of the degradation threat. The same technique was used to create the final map showing the most troubled areas in the Czech Republic, threatened by soil damage.

Isolation of Rhodotorula mucilaginosa from skin lesions in a Southern sea lion (Otaria flavescens): a case report

S. Alvarez-Perez, A. Mateos, L. Dominguez, E. Martinez-Nevado, J.L. Blanco, M.E. Garcia

Vet Med - Czech, 2010, 55(6):297-301 | DOI: 10.17221/2988-VETMED

This paper reports the isolation of Rhodotorula mucilaginosa from skin lesions in a Southern sea lion (Otaria flavescens). The microorganism was isolated from cutaneous lesions, identified by the commercial API 20 C AUX system, and confirmed by sequencing. Topical treatment with sertaconazol resulted in complete clinical recovery of the animal and repeat testing did not result in the recovery of the yeast from the healed lesion sites.

Image vision technology for the characterisation of shape and geometrical properties of two varieties of lentil grown in Turkey

Ebru Firatligil-Durmuş, Evžen Šárka, Zdeněk Bubník

Czech J. Food Sci., 2008, 26(2):109-116 | DOI: 10.17221/1/2008-CJFS

Geometrical features of lentil seeds (Lens culinaris Medik) were analysed using the image analysis LUCIA system Ver. 3.52. The values of the weight of 1000 kernels, kernel density, specific volume, specific surface area, and surface area of 1000 kernels of red and green lentils were determined as 66.61 and 138.56 g, 1504.5 and 1376.4 kg/m3, 0.6647 and 0.7265 cm3/g, 0.594 and 0.579 m2/kg, 395.4 and 801.9 cm2,, respectively. The lentil volume was simulated by an oblate spheroid and two sphere segments and the volumes obtained with both models were compared with that obtained by pycnometric method. Percentage differences of the two sphere segment approximation for red and green lentils were 4.4% and 4.2%, respectively. The height (thickness) of lentils was constant and practically the same with both varieties (2.6 mm) and therefore it was possible to simplify the geometrical models. Thus, 2D image analysis is suitable for a quick evaluation of the specific volume and surface area of grains on the basis of the projected area (equivalent diameter) without the measurement of the height. Image processing provides a simple, rapid, and non-invasive methodology to estimate lentil geometric features and engineering parameters.

Authenticity evaluation of tea-based products

H. Čížková, M. Voldřich, J. Mlejnecká, F. Kvasnička

Czech J. Food Sci., 2008, 26(4):259-267 | DOI: 10.17221/10/2008-CJFS

This study proposes a method for estimating the content of tea in tea-based products. Broadly, this methodology is based on selecting chemical markers of the quality and authenticity of tea (and, therefore, of tea-based products), optimising the relevant analytical methods, and determining variations (type, origin, quality) among samples of green and black leaf teas. The contents of the selected markers (theobromine, caffeine, theanine, and total polyphenols) in tea-based products (iced teas, instant teas) were determined. Then, the dry tea content in these products, expressed as the equivalent amount of dry tea leaves, was calculated on the basis of two sets of mean data for these analytes: average literature data, and the mean experimental data obtained with our samples of leaf tea. With regards to the latter, we propose to use of the following averages for caffeine, theobromine, theanine, and polyphenols: for 100 g of black tea-based products 1.9 g, 0.13 g, 1.3 g, and 9.1 g, respectively; for 100 g of green tea-based products 1.9 g, 0.16, 1.7 g, and 14.7 g, respectively. Using this method, we found that approximately one third of the analysed samples failed to meet the tea extract levels required by German and Austrian legislations, while about 10% did not comply with the less demanding Czech legislative requirements.

The effect of oviposition time and genotype on egg quality characteristics in egg type hens

E. Tůmová, L. Zita, M. Hubený, M. Skřivan, Z. Ledvinka

Czech J. Anim. Sci., 2007, 52(1):26-30 | DOI: 10.17221/2326-CJAS

In an experiment with three strains of Dominant genotype the effect of oviposition on egg quality characteristics was investigated. Laying hens of the Blue strain (group 1), Plymouth Rock (group 2) and their F1 cross (group 3) from 20 to 64 weeks of age were housed on litter (9 birds per m2). The collection time was at 6.00, 10.00 and 14.00 h. Eggs were gathered in a 28-day interval, every two days all produced eggs (720 eggs in total). The time of oviposition was influenced by genotype. The highest number of eggs was collected in the Plymouth Rock strain at 6.00 (53.5%) and the lowest in the Blue strain at 14.00 (11.1%). There were interactions between the time of oviposition and genotype in egg weight. Eggs laid in the morning at 6.00 were significantly heavier (60.5 g, 64.9 g and 62.1 g) in comparison with eggs laid in the afternoon (59.3 g, 62.4 g and 62.7 g). The heaviest eggs were produced by the Plymouth Rock strain. Significant interactions were observed in eggshell weight when the heaviest eggshell was in afternoon eggs (5.6 g, 5.8 and 5.9 g) and F1 genotype. The egg shape index was also affected by the genotype and time of oviposition. Among the albumen quality characteristics only Haugh Units were influenced by genotype and significantly higher numbers were determined in the Plymouth Rock strain (85.0, 85.3 and 84.7). The genotype significantly affected also the yolk index which was the highest in F1 genotype (45.4%, 45.4% and 44.5%).

Fractionation and identification of some phenolics extracted from evening primrose seed meal

Lucia Zahradníková, Štefan Schmidt, Zuzana Sékelyová, Stanislav Sekretár

Czech J. Food Sci., 2008, 26(1):58-64 | DOI: 10.17221/1135-CJFS

Crude ethanol and ethyl acetate extracts of evening primrose (Oenothera biennis L.) seed meal were separated into fractions using Silicagel L 100/200 column chromatography and methanol as the mobile phase. Six fractions were obtained from the ethanol extract and five fractions from the ethyl acetate extract and their contents of total phenolics were determined. By means of HPLC, the active compounds were identified as catechin, gallic acid, caffeic acid, syringic acid, and ferulic acid.

Functional bioactive compounds and biological activities of Spirulina platensis lipids

Mohamed Fawzy Ramadan, Mohsen Mohamed Selim Asker, Zeinab K. Ibrahim

Czech J. Food Sci., 2008, 26(3):211-222 | DOI: 10.17221/2567-CJFS

The compositions and concentrations of lipid classes, fatty acids, tocopherols were determined in the lipids from blue-green microalga Spirulina platensis. Total lipids (TL) recovered using chloroform: methanol (2:1, v/v) were found to be 163.5 g/kg (on dry weight basis). The level of neutral lipids was the highest, followed by glycolipids and phospholipids, respectively. Among TL and lipid classes, palmitic, γ-linolenic and linoleic acids were the dominating fatty acids. Compared to the neutral lipids, the polar fractions were generally characterised by higher percentages of saturated fatty acids. The recovered lipids were characterised by high percentage of tocopherols, wherein γ-tocopherol constitutes about 73% of total tocopherols present, the rest being γ-tocopherol. Spirulina platensis lipids exhibited a strong radical scavenging activity towards stable DPPH free radicals, whereas 27% of DPPH radicals were quenched after 2 h incubation. TL and lipid classes inhibited the growth of different microorganisms except gram-negative bacteria. At high concentrations, the tested lipids appeared more effective against A. niger (28.3 ± 1.53 mm). The information obtained in the present investigation is useful for lipid characterisation and further chemical and nutritional investigations of Spirulina platensis.

Nondestructive identification of tea (Camellia sinensis L.) varieties using FT-NIR spectroscopy and pattern recognition

Quansheng Chen, Jiewen Zhao, Muhua Liu, Jianrong Cai

Czech J. Food Sci., 2008, 26(5):360-367 | DOI: 10.17221/1125-CJFS

Due to more and more tea varieties in the current tea market, rapid and accurate identification of tea (Camellia sinensis L.) varieties is crucial to the tea quality control. Fourier Transform Near-Infrared (FT-NIR) spectroscopy coupled with the pattern recognition was used to identify individual tea varieties as a rapid and non-invasive analytical tool in this work. Seven varieties of Chinese tea were studied in the experiment. Linear Discriminant Analysis (LDA) and Artificial Neural Network (ANN) were compared to construct the identification models based on Principal Component Analysis (PCA). The number of principal components factors (PCs) was optimised in the constructing model. The experimental results showed that the performance of ANN model was better than LDA models. The optimal ANN model was achieved when four PCs were used, identification rates being all 100% in the training and prediction sets. The overall results demonstrated that FT-NIR spectroscopy technology with ANN pattern recognition method can be successfully applied as a rapid method to identify tea varieties.

The effect of growth and development intensity in replacement heifers on economically important traits of Holstein cattle in the Czech Republic

J. Bouška, M. Štípková, M. Krejčová, L. Bartoň

Czech J. Anim. Sci., 2007, 52(9):277-283 | DOI: 10.17221/2263-CJAS

The objective of the study was to determine the effect of growth and development intensity in Holstein replacement heifers on economically important animal traits. The intensity of growth was assessed by the average live weight gain until 14 months of age. In addition, live weight and height at the sacrum at 14 months of age were analysed as indicators of growth and development when evaluating the length of productive life. The milk yield of first-calvers increased as the average daily live weight gain in the rearing period increased. An opposite tendency was recorded for cows in their second and third lactation and the total production also decreased with a higher growth rate of heifers. The analysis of the relationship between growth rate and the following reproduction traits revealed that the increased average daily live weight gain to 14 months was subsequently associated with reduced reproduction efficiency in cows. The differences between the groups with the lowest and the highest average live weight gains in the number of days open in the first and second calving interval were 26.78 and 17.47 days, respectively. This tendency was also confirmed in the other reproduction traits analysed. Productive life was significantly longer in animals with the lowest intensity of growth and development compared to the other groups (2.17 to 5.49 months, P < 0.01).

Influence of Alcalase and transglutaminase on immunoreactivity of cow milk whey proteins

Barbara WRÓBLEWSKA, Lucjan JĘDRYCHOWSKI, Gyongyi HAJÓS, Erzsebet SZABÓ

Czech J. Food Sci., 2008, 26(1):15-23 | DOI: 10.17221/1141-CJFS

The aim of the research was to determine the changes in the immunoreactivity of whey protein concentrate (WPC) modified by two enzymes: proteinase, Alcalase 2.4L FG (Novo Nordisk), and cross-linked transglutaminase (EC 2.3.2.13, ActivaTM P, m-TG, Ajinomoto). The new products were characterised by 2D electrophoresis, immunoblotting, and ELISA methods. The WPC hydrolysate obtained with Alcalase contained proteins and peptides characterised mostly by low molecular weight peptides (MW < 14.4 kDa) in the pH range of 3-10. Immunoblotting showed strong immunoreactive properties of the hydrolysate with α-la and β-lg polyclonal rabbit antibodies. The 2D electrophoretic patterns of WPC and its modified product obtained with m-TG did no differ significantly. However, the immunoblot analysis demonstrated that WPC showed a stronger reactivity towards IgE of allergic patients as compared to WPC with m-TG. ELISA methods showed that two-step hydrolysis with Alcalase followed by m-TG significantly reduced the immunoreactive properties of whey proteins. No cross reactions were observed with α-la and only about 0.6% cross-reactivity with β-lg.

Antioxidant activity, β-glucan and lipid contents of oat varieties

Lucia Brindzová, Milan Čertík, Peter RAPTA, Michal Zalibera, Anna Mikulajová, Mária Takácsová

Czech J. Food Sci., 2008, 26(3):163-173 | DOI: 10.17221/2564-CJFS

The antioxidant activity, total phenolic and β-glucans contents, and the fatty acid profile of total lipids in covered (black and yellow) and naked oats were studied. Oats with black hulls showed a significantly higher antioxidant activity in 2,2'-azino-di-[3-ethylbenzthiazoline sulphonate] (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) based tests in comparison to the grains with yellow hulls and those of the naked varieties. Radical scavenging activity of oats determined by electron paramagnetic resonance (EPR)/spin-trapping test did not depend on the colour of the grain hulls, but the naked grains showed a lower ability in scavenging reactive radicals. A positive correlation between the content of β-glucans in covered oat grains and the amount of reactive radicals scavenged was observed. Total phenolic content in the black oats was significantly higher than in the yellow and naked oat varieties. However, no significant differences in the fatty acid profile between the naked and covered oats were found, and the common fatty acids being linoleic, oleic, and palmitic acids.

Biofilms and hygiene on dairy farms and in the dairy industry: sanitation chemical products and their effectiveness on biofilms - a review

Hana Vlková, Vladimír Babák, Růžena Seydlová, Ivo Pavlík, Jarmila Schlegelová

Czech J. Food Sci., 2008, 26(5):309-323 | DOI: 10.17221/1128-CJFS

Microbial biofilms which form on all types of surfaces of technological systems in the dairy industry and on dairy farms adversely affect the quality and safety of final products, i.e. both foodstuffs and raw materials used for their production. The fact that a number of microorganisms are alimentary pathogens, e.g. Staphylococcus aureus or Listeria monocytogenes, makes a serious problem directly affecting human health. Biofilms are usually formed by various species of microorganism, which protect each other against the effects of biocidal (antibacterial) agents and are resistant to these agents. The colonisation of surfaces of the open and closed piping systems, floors, waste, walls and ceilings of the production halls becomes a major problem in the selection of effective sanitation agents for their control. Based on the existing model studies, practical methods for testing the effectiveness of sanitation procedures should be evaluated, including the selection of biocides and comparison of the physical parameters of the sanitation procedures. Testing the effectiveness of the sanitation agents should be performed with the use of standardised tests, which consider microbial, structural, and chemical characteristics of the living microbial communities on specific contact surfaces in the food-processing industry.

Mushrooms of genus Pleurotus as a source of dietary fibres and glucans for food supplements

Andriy Synytsya, Kateřina Míčková, Ivan Jablonský, Marcela SLUKOVÁ, Jana Čopíková

Czech J. Food Sci., 2008, 26(6):441-446 | DOI: 10.17221/1361-CJFS

Fruit bodies (separately pilei and stems) of mushrooms Pleurotus ostreatus (four strains) and Pleurotus eryngii were characterised as a source of polysaccharides. The contents of glucans and dietary fibres were determined with using the respective Megazyme enzymatic kits. Enzymatic analysis of the fruit bodies confirmed significant differences in the contents of these components among the species and strains. The stems contained more insoluble dietary fibres than the pilei in all the cases and more β-glucans in most cases. However, relatively high contents of β-glucan (20-50% of dry matter) could be a result of incomplete enzymatic hydrolysis of insoluble α-1,3-glucans. Nevertheless, low food quality stems of mushrooms Pleurotus sp. could be a valuable source of cell wall glucans for the preparation of food supplements.

Formation of carboxylic acids during degradation of monosaccharides

Ondřej Novotný, Karel Cejpek, Jan Velíšek

Czech J. Food Sci., 2008, 26(2):113-131 | DOI: 10.17221/2465-CJFS

The formation of low molecular carboxylic and hydroxycarboxylic acids as well as sugar and deoxysugar acids from monosaccharides (D-glucose, D-fructose, D-arabinose, DL-glyceraldehyde, and 1,3-dihydroxyacetone) was studied in three different model systems: aqueous and alkaline solutions of potassium peroxodisulfate (K2S2O8), and sodium hydroxide solution. In total, 3 low molecular carboxylic acids (formic, acetic and propionic), 24 hydroxycarboxylic acids, and 12 corresponding lactones were identified and quantified by GC/MS. Formic, acetic, and propionic acids were isolated by extraction with diethyl ether and directly analysed by GC/MS; hydroxycarboxylic acids and their lactones were monitored as their trimethylsilylated derivatives using the same method. Formic, acetic, L-lactic, glycollic, DL-2,4-dihydroxybutanoic acids and aldonic acids derived from the parent sugars were the most abundant compounds in all model systems. Within the models investigated, the yield of carboxylic acids and hydroxycarboxylic acids (together with their lactones) ranged between 9.3-22.2% (n/n) and between 3.6-116.9% (n/n), respectively. The amount of acids was significantly lower in aqueous solutions of K2S2O8 than in the alkaline solutions. The data obtained indicate that lower carboxylic acids are formed by both subsequent reactions (oxidation and/or intramolecular Cannizzaro reaction) of the sugar fragmentation products and direct decomposition of some intermediates such as uloses or hydroperoxides derived from the parent sugars. The acids possessing the original sugar skeleton are formed as a result of sugar oxidation or benzilic acid type rearrangement of deoxyuloses. Lower acids may also be formed by a recombination of free radicals.

Extraction of carrot (Daucus carota L.) carotenes under different conditions

Martina Fikselová, Stanislav Šilhár, Ján Mareček, Helena Frančáková

Czech J. Food Sci., 2008, 26(4):268-274 | DOI: 10.17221/9/2008-CJFS

This paper describes carotenes extraction from carrot under different conditions involving different temperatures, treatment of samples, and solvents (ethanol, 2-propanol). Carrot roots (Daucus carota L. cv. Nevis F1) were tested for the extraction yields of carotenes at temperatures 20°C, 40°C, and 60°C, the samples having been examined after harvest, after cold storage (stored at 5°C), and after freezing (-18°C). In connection with the technology of the carotenoid concentrate production from carrots, it was found that the solubility and yield of carotene from carrot depend on the temperature and the time of extraction as well as the treatment of the sample. It was revealed that the best extraction efficiency was achieved with the samples treated by freezing and using the extraction 60°C for 2-4 hours. Higher temperatures caused an increase in the carotenoid concentrations. The carrot variety Nevis F1 and the extraction at 60°C were used for the model production of carotenoid concentrate.

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