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Evaluation of a headspace solid–phase microextraction with different fibres for volatile compound determination in specialty coffee brews 全文
2019
Laukaleja, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Kruma, Z., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
The aroma of coffee is the main quality factor. Compounds with floral, fruity, citrus and sometimes fermented aroma notes are defined as high quality characteristics for the specialty coffee brew. Commercial coffees mostly are at medium roast and the aroma profile is focused on balanced chocolate, caramel, toasted bread and almond bitterness aroma notes. These sensory characteristics set the focus for volatile compound profile analysis by Headspace solidphase microextraction (HS-SPME). The most popular fibres for commercial coffee aroma profile analysis are DVB/ CAR/PDMS, CAR/PDMS, PDMS/DVB and PA. There is limited research done about specialty coffee aroma profile and evaluation of more suitable fibres for solid-phase microextraction. The aim of the research is to evaluate the aroma composition of specialty coffee brews using different SPME fibres. Results demonstrated that CAR/PDMS fibre, compared to other fibres, can extract significantly more volatile compounds with higher peak areas in all chemical compound groups, except phenols. The CAR/PDMS was the only fibre which could detect all 17 important volatile compounds for specialty coffee. In conclusion, from the given research evidence, CAR/PDMS fibre is suggested as the most suitable SPME fibre coating for volatile compound extraction for specialty coffee brew import. The result provides evidence for improved specialty coffee aroma profile analysis by SPME.
显示更多 [+] 显示较少 [-]Determination of organic acids in honey samples from Latvian market by high-performance liquid chromatography 全文
2019
Keke, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Cinkmanis, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Determination of organic acids in honey samples from Latvian market by high-performance liquid chromatography Honey is a naturally sweet product, which is produced by honeybees (Apis mellifera). Honey is a natural source of antioxidants and has been known to mankind since ancient times. Honey contains approximately 200 different compounds. Organic acids can be used as an indicator to detect the freshness, authenticity and acidity of honey. The aim of this research was to determine and quantify organic acids such as oxalic, L-tartaric, D-quinic, L-malic, L-ascorbic, citric, fumaric and succinic in honey samples from Latvian market u sing high-performance liquid chromatography. The chromatographic separation of organic acids was carried out with PerkinElmer C18 (4.6 mm Í 250 mm I.D, particle size 5 mm) analytical column at the temperature of 35 °C in wavelength at 210 nm. The obtained results showed that the analysed honey samples contain L-tartaric, D-quinic, L-malic, L-ascorbic, citric, fumaric and succinic acids. The concentration of these acids was found to be variable. Oxalic acid was not detected in the analysed honey samples. L-tartaric acid was the main acid in all analysed honey samples.
显示更多 [+] 显示较少 [-]Preliminary study of bovine colostrum quality in Latvia 全文
2019
Baltrukova, S., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia) | Zagorska, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Eihvalde, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Bovine colostrum is a mammary gland secret which, due to its high immunoglobulin concentration, is necessary for the transfer of passive immunity to the calf, preventing diseases caused by microbial infections in the newborn ruminants. Colostrum, however, may contain pathogens and can be an infection transmitter, affecting morbidity and mortality rates of calves in the farms. Total plate count and immunoglobulin concentration are two main factors affecting colostrum quality, therefore the aim of the study was to analyse Latvian dairy herd colostrum quality. Colostrum was collected from Holstein Black cows within the first six hours after calving, lactation period of animals ranged from 1st to 4th lactation. Colostrum samples (n=51, 50 mL) were collected from December 2018 to February 2019. Immunoglobulin concentration (n=51) was defined by colostrometer (COLOSTROMETERtm Biogenics, USA), total solids content by optical refractometer (Model BX, UK). Staphylococcus spp. colony–forming unit (CFU) (LVS EN ISO 6888-1+A1:2007), the presence of Listeria spp. (LVS EN ISO 11290-1+A1:2007) and Salmonella spp. (LVS EN ISO 6579-1:2017) were examined in the colostrum samples (n=20). Despite the high immunoglobulin concentration in the analysed samples, our research findings demonstrate suboptimal colostrum quality received by calves. That indicates the necessity for regular colostrum quality control and better management practise providing on the farm.
显示更多 [+] 显示较少 [-]Health status of gene fond donor cows of Latvian native breeds Latvian Brown and Latvian Blue 全文
2019
Ringa-Karahona, G., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia) | Sematovica, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Antane, V., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Mangale, M., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
The preservation of local animal breeds is a topical theme in recent years. Latvian Brown (LB) and Latvian Blue (LZ) cow breeds are exhausting and must be preserved. It can be performed by the use of multiple ovulation and embryo transfer (MOET). The difficulties exist in choosing the gene-fond (GF) cows as donors caused by the small number of animals. Twenty-three cows were intended for donor cow’s role from different herds until September 2018, and twenty of them were accepted. Anamnesis, clinical examination, blood morphology (13 parameters) and biochemical indices (19 parameters) were analysed before MO induction. Three cows were rejected because of ovarian cysts or pyometra, negative energy balance (NEB) (glucose is less than 2.3 mmol LE−1 simultaneously with elevated ß-hydroxybutyric acid is greater than 1.4 mmol LE−1) and elevated (p is less than 0.05) number of leukocytes (28.20 x109 LE−1). More than 52.6% of cows had a repeated artificial insemination before the last parturition, and 5.3% of cows had lifeless offspring in the last parturition. The 1st and 2nd lactation cows were healthier than older cows (p is less than 0.05). The amount of albumins, cholesterol, triglycerides and Na, K, P, Cl, Mg was significantly different in donors with and without successfully obtained embryos (p is less than 0.05). In conclusion, not only acceptable clinical health but also the cow metabolic status is a decisive factor for success of MOET.
显示更多 [+] 显示较少 [-]The effect of dietary β-glucans supplements on the haematological parameters of the sea trout 全文
2019
Revina, O., Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia);Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia) | Revins, V., Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia) | Cirule, D., Institute of Food Safety, Animal Health and Environment “BIORˮ, Riga (Latvia) | Valdovska, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
In recent years, the effective immunostimulating properties of β-glucans have been widely proven not only in mammals, but also in aquatic animals. The aim of this study was to determine the effect of dietary β-glucan supplements on the percentage of individual types of leukocytes and the haematocrit of the sea trout (Salmo trutta L.). Investigations were performed at the state fish farm ‘Tome’, hatchery ‘Pelči’ of the Institute of Food Safety, Animal Health and Environment ‘BIOR’, during a six month period (September 2018 – February 2019). On the basis of feeding with immunostimulant diets, a total of 15 000 sea trout were assigned into five groups. For blood collection healthy fish were randomly selected once a month, five 5 individuals from each group. Blood smears were made to determine the leukocyte differential count. Sampling was done once a month (September 2018 – January 2019) (n=125). Haematocrit was determined by the standard microhaematocrit method. Sampling was done once a month (January 2019 – February 2019) (n=50). We concluded that the dietary β-glucan supplements can improve the haematocrit level and effect the percentage of individual types of leukocytes of the sea trout, stimulation of the preparation for parr-smolt transformation.
显示更多 [+] 显示较少 [-]Histopathological changes in liver of elks with Parafasciolopsis fasciolaemorpha invasion 全文
2019
Bergmane, B., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Berzina, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Visocka, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Parafasciolopsosis is a parasitological disease which is caused by the liver fluke Parafasciolopsis fasciolaemorpha. This parasite which belongs to herbivores often causes invasion in elks (Alces alces). The aim of our study was to diagnose the parasite and investigate what kind of histopathological changes it caused in the liver tissue. The study took place in Latvia University of Life Sciences and Technologies, Faculty of Veterinary Medicine, Laboratory of Comparative Pathology and Laboratory of Parasitology. During the study from 2017 to 2018 we collected liver samples and faeces from 46 felled elks of different age and gender, from all over Latvia. Ten grams of faeces were examined for trematode eggs by sedimentation method and a section of liver was examined for the presence of flukes and the histological structure of the liver. In this study Parafasciolopsis fasciolaemorpha were found in 11 samples of liver from 46 elks, with invasion extensity of 24%. The histopathological examination of the liver samples revealed fibrosis, proliferation of bile ducts, pericholangitis, calcerous deposits in bile ducts and other notable histological changes in the liver tissue that can cause hepatic trematodes.
显示更多 [+] 显示较少 [-]Above-ground and seed bank weed biodiversity comparison in conventional and organic farming systems in Poland 全文
2019
Berbec, A.K., Institute of Soil Science and Plant Cultivation, State Research Inst., Pulawy (Poland) | Feledyn-Szewczyk , B., Institute of Soil Science and Plant Cultivation, State Research Inst., Pulawy
The assessment and conservation of agricultural biodiversity is one of the current goals of European Union policies, which are reflected in European Biodiversity Strategy. The biodiversity of soil seed bank and above-ground weed flora were investigated in spring cereals in organic and conventional farming system. The study was carried out between 2012 and 2014. Species of above-ground wild flora were counted on a surface of 1 square m in the field. Soil for seed bank evaluation was taken from the field and evaluated by seedling emergence method in a greenhouse. There were no significant differences in number of species between two communities. Biodiversity of weed community, described by Shannon’s diversity index and Simpson’s dominance index, was significantly better maintained in the soil seed bank than in above-ground flora in both farming systems. A strong, positive correlation between the number of species, Shannon’s diversity index, Simpson’s dominance index of soil seed bank and above-ground weed species was found in both farming systems, while abundance of seeds and above-ground weeds was significantly, positively correlated only in the conventional farming system. Qualitative composition of weed flora depended more on the type of community (soil seed bank or above-ground weed communities) than the farming system.
显示更多 [+] 显示较少 [-]Assessment of spring barley populations in comparison to homogenous varieties 全文
2019
Locmele, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvia Univ. of Life Sciences and Technologies, Priekuli, Priekuli Parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics | Legzdina, L., Latvia Univ. of Life Sciences and Technologies, Priekuli, Priekuli Parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics | Piliksere, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Kronberga, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvia Univ. of Life Sciences and Technologies, Priekuli, Priekuli Parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics
The necessity to increase genetic diversity in agriculture has been widely discussed during the last decades. Heterogeneous populations are one of the ways to increase genetic diversity in varieties of self-pollinating cereals. The aim of this research was to compare grain yield, its stability, foliar diseases severity and competitiveness against the weeds of spring barley (Hordeum vulgare) populations and homogenous varieties. Field trials consisting of three types of populations (simple, complex and composite cross populations – CCP) containing different levels of diversity and three check varieties were carried out during 2015−2018 under organic and conventional farming systems. No one of the populations had a significantly higher average yield than any of the check varieties. CCP1 showed a tendency to be more productive under organic growing conditions and can be characterized as widely adaptable to various growing conditions with a significantly higher yield as the average overall environments. One of the complex populations showed adaptability to favourable growing conditions and yield insignificantly higher than overall average. Other studied populations can be characterized with wide adaptability and various yield levels. For most of the populations under organic and conventional conditions, a significantly lower net blotch (caused by Pyrenophora teres) severity was observed in comparison with the most susceptible variety; infection with powdery mildew (caused by Blumeria graminis) lower than for check varieties was observed under organic growing conditions, whereas such trend was not observed under conventional conditions. All populations had a significantly lower crop ground cover and slightly lower competiveness against weeds than the variety with the best competitiveness
显示更多 [+] 显示较少 [-]Botrytis genus fungi as causal agents of legume diseases: a review 全文
2019
Brauna-Morzevska, E., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);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) | Kaneps, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Grain legumes are important crops for the diversification of European farming system. In Latvia, the areas of faba beans (Vicia faba) and field peas (Pisum sativum) are increasing and legumes that have not been previously cultivated are sown. Globally, the important causal agent of legume diseases belongs to the genus Botrytis. Botrytis spp. cause significant losses in faba beans and infect a wide range of legume crops. Currently, the composition, pathogenicity and biological characteristics of Botrytis species in legumes in Latvia are not known. The aim of this study was to summarize the information about Botrytis spp. on legumes, using monographic method. The researches carried out all over the world show a high genetical diversity of Botrytis cinerea. Non-host specific B. cinerea has been found on 586 plant genera, including many legume crops. B. cinerea causes gray mold on leaves and pods of field peas, gray mold on pods of faba beans, and chocolate spot of faba bean leaves. B. fabae can infect plants from Fabaceae family. B. fabiopsis is known as a pathogen of faba beans. B. fabiopsis has been observed in Latvia, but no information is available on its presence in Europe. B. pseudocinerea has been found on beans, peas, and clover (Trifolium). Some other Botrytis spp. have been detected on legumes; however, their occurrence and importance are not clear. Summary of existing knowledge about Botrytis spp. on legumes is necessary to continue investigations about the diversity and economic importance of Botrytis spp. in legumes.
显示更多 [+] 显示较少 [-]Characterization of Puccinia recondita, the causal agent of brown rust: a review 全文
2019
Peksa, K., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvia Univ. of Life Sciences and Technologies, Priekuli, Priekuli Parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics | Bankina, B., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Brown rust caused by Puccinia recondita is a significant disease in cereal growing areas worldwide. On average, brown rust can cause yield losses from 10% to 40% resulting in economic losses. The disease damages the leaves, stems and glumes of cereals. Classification of the pathogen causing brown rust has undergone several revisions. There are two different opinions about the causal agent causing brown rust on rye and wheat. Some scientists consider that the causal agent of brown rust in wheat (Triticum aestivum L.) and rye (Secale cereale) is included in the broad species of P. recondita defined by Cummins, but other scientists consider that there are two species causing brown rust – P. recondita in rye and P. triticina in wheat. There are many studies about the races of P. recondita in wheat: in North America, 70 races are collected every year; in Canada, 35 races have been found; in Europe, 105 races have been found. Unfortunately, there are no studies about the races of the pathogen of rye. P. recondita is a heteroecious fungus with a complicated life cycle. For successful development, the fungus requires cereals as primary hosts and different alternative hosts, depending on the specialization of the pathogen. Specific studies about the biology, distribution and harmfulness of Puccinia recondita in Latvia are necessary. Monographic method was used for this study. The aim of this article is to summarize the information from the literature about Puccinia recondita, the causal agent of brown rust, with emphasis on the occurrence, harmfulness, taxonomy, and life cycle of P. recondita f. sp. secalis.
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