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.

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.

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.

The aim of this pilot study was to assess whether a single mesenchymal stem cell intra-articular injection in the osteoarthritic joint gives a therapeutic effect. This trial study was made in order to better manage and structure further study on more dogs. Single injections of 3 million mesenchymal stem cell intra-articular injections were made bilaterally in the osteoarthritic elbow joints. The dog was examined before and after monthly stem cell therapy using stance analyser scales to determine the static weight of each limb. Weight balance between forelegs improved, but not significantly (p is greater than 0.05). A radiographic examination was made for both elbow joints before stem cell therapy and the second and fifth month thereafter. Calculations of sub-trochlear sclerosis in percentage were made using mediolateral projections. Sub-trochlear sclerosis in percentage significantly decreased (p is less than 0.05) after stem cell therapy in both legs.

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.

The feature of the microorganisms of rumen microbiocenosis is the ability to form a number of digestive enzymes, including cellulases, which allows ruminants use the energy of feeds rich in fiber. Microorganisms that are promising as a source of cellulases, biodestructors of toxins having antagonistic properties against pathogens for creating probiotic feed additives, both for reindeer and for other livestock, were isolated from the reindeer rumen. The aim of the study was to create a collection of microorganisms that are promising for creating a biopreparation. As a result, collections of 63 associations of microorganisms decomposing cellulose and carboxymethylcellulose were created; their morphology and cultural properties were described. It was found that the amount of cellulose degradation was 44 – 62% in the 4 most active isolates (No 14, 15, 21 and 26). The obtained data allowed to make a conclusion about the ability of bacterial strains isolated from the rumen to synthesize cellulolytic enzymes carrying out cellulose biodegradation, which allows them to gain a competitive advantage in the rumen of the reindeer diets with an abundance of cellulose. Isolates No 14 and 15 showed high antagonistic activity to Fusarium sporotrichioides, and isolate No 15 and 16 showed high antagonistic activity to Fusarium oxysporum. Isolate No 15 showed a wider antifungal activity compared to other isolates. Among all isolated strains, this bacterial isolate is represented as having a large spectrum of activities, including both high cellulolytic and high antifingal activity.

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.

The impacts of agricultural policies are decisive on the agricultural sector, especially in the case of the European Union’s (EU) Common Agricultural Policy (CAP). The 2013 CAP reform introduced several new measures. In budgetary terms, basic payment and greening were the most significant ones. Besides, coupled supports, young farmer and small farmers scheme should be mentioned. To reveal the changes caused by these measures, the time horizon of the study is 2013−2017. Since the subsidies represent a significant part of the income generated in the agricultural sector, the basic hypothesis of the study is that the production units concerned (individual farms, private enterprises) gave economically rational answers. In practice, this means trying to fully adapt to the changes to maximize support. Based on the analysed datasets (Hungarian Central Statistical Office and Hungarian State Treasury), it became evident that farmers responded rationally: splitting up farms against capping, moving towards the lowest resistance to comply with greening, plus associating them with the extra support of coupled payments. Generational renewal is a key issue; however, the present form of young farmers’ scheme needs to be refined to be more effective. Small farmers scheme is a good opportunity for farmers with less than 5.5 ha and most of the concerned farmers chose well. However, there are about 6,000 farms that are too small for the standard system, while 772 farms that are too large for the small farmers scheme.

Winter oilseed rape is the main oilseed crop in Latvia. High yield production depends on applied plant nutrients, especially nitrogen. Nitrogen is one of the most mobile plant nutrients in the soil and, therefore, nitrogen fertilizer management is an important part of agriculture. The objective of this paper is to evaluate the effect of nitrogen fertilizer rate on nitrogen use efficiency (NUE) in winter oilseed rape. The field experiment was conducted during four growing seasons (2014/2015, 2015/2016, 2016/2017 and 2017/2018) at the Research and Study farm ‘Pēterlauki’ of Latvia University of Life Sciences and Technologies (56° 30.658´ N and 23° 41.580´ E). In total, eight nitrogen rates were used in this experiment (kg ha-1 of N pure matter): N0 or control, N60, N90, N120 (80+40), N150 (100+50), N180 (120+60), N210 (120+60+30) and N240 (140+60+40). All NUE parameters were calculated only for five nitrogen rates (N0; N60, N120, N180 and N 240). Results indicated that the nitrogen fertilizer rate had a significant (p is less than 0.001) effect on winter oilseed rape seed yield. The yield increased until the rate N120 – N180. Nitrogen fertilizer rate also significantly (p is less than 0.001) affected N, P2 O5 and K2 O removal with oilseed rape biomass. N and K2 O removal with seed yield significantly increased until the nitrogen rate N120 – N180, but P2 O5 until N60 – N180. Results showed that the nitrogen fertilizer significantly (p is less than 0.001) affected NUE, nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE), but it did not have a significant (p=0.840) effect on nitrogen harvesting index (NHI). By increasing the nitrogen fertilizer rate, NUE, NUpE and NUtE decreased.

New types of polymer fertilizer series ‘Vitanoll’ are used in adaptive-varietal agro technology in the cultivation of seed potatoes. The experiments were conducted on sod-podzolic soils, typical of the North-West region of the Russian Federation. The aim of the research was to study the effect of new polymer fertilizers on potato yield. Research tasks included assessing the effect of various polymer fertilizers (Polymer-N, Polymer-P, Polymer-K.), as well as the effect of Polymer-N on different potato varieties. Based on the studies conducted, the most responsive potato varieties to polymeric fertilizers with nitrogen were identified. They turned out to be Salin (increase of 7.1 t haE−1) and Mocart (increase of 4.1 t haE−1). Evaluation of the influence of different types of polymer fertilizers revealed that the most effective are polymer fertilizers with potassium.