خيارات البحث
النتائج 51 - 60 من 97
Impacts of municipal wastewater treatment plants on water quality in the Berze River basin [Latvia] النص الكامل
2017
Dambeniece-Migliniece, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lagzdins, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Eutrophication caused by water pollution with nutrients (nitrogen (N) and phosphorus (P)) is one of the main environmental problems nowadays. Poor water quality might be caused by many natural and anthropogenic factors. The most common anthropogenic factors are water pollution caused by intensive agriculture (e. g. intensive fertilizer use, high density of livestock) and discharges from municipal waste water treatment plants (WWTP). In this study, nutrient load from WWTP to the River Berze basin in time period from the year 2005 to the year 2015 was described. In total, 23 WWTPs of the study area were analysed using descriptive statistics to calculate average values of nutrient amount and concentrations discharged to River Berze basin. From 2005 to 2015 average N and P load from WWTP to the River Berze basin have been reduced, but concentration of N and P in treated wastewater (WW) have increased. The largest WWTP of the study area – Krigeri (WWTP of city Dobele) is subject to the regulations of treated WW quality set by Republic of Latvia Cabinet Regulation No. 34. The WWTP Krigeri meets the regulations, but overall situation in the study area suggests that strict control of smaller WWTP should be made.
اظهر المزيد [+] اقل [-]Importance of landscape elements in perception of spatial aesthetics in residential areas النص الكامل
2017
Kusmane, A.S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ile, U., Latvia Univ. of Agriculture, Jelgava (Latvia)
Our previous research was focussed on evaluating spaces in the Soviet period housing estates in Riga according to theoretical model of spatial measurements. This model was based on assumption established ex situ that liking and perception of urban space is closely related to buildings. Namely, to the way walls of the buildings shape a setting in terms of its height, width, length. This current paper sets the goal to analyse the impact of landscape elements such as trees, benches, elevations of earth surface, playgrounds on the perception and preference of open spaces in situ. This is done to verify the hypothesis that landscape elements as well as the method of research play a role in our knowledge on how urban spaces are regarded. Semi-structured interviews in walk-along modus are used to talk to inhabitants about the ways they see and like yards and streets in three residential areas: ‘Agenskalna priedes’, ‘Kengarags’, ‘Zolitude’. The interview materials are analysed discursively. The extracted information is compared to the data previously acquired by using the model of spatial measurements. The results of interviews show that trees are the landscape elements that have the largest impact on how residents perceive the size of a space and how they like a setting. There are also other elements such as benches, playgrounds, elevations that play a role. The interview material displays deviations in preference and perception of the size of space compared to the model of spatial measurements. Yet these deviations can be adapted to the model.
اظهر المزيد [+] اقل [-]Effect of high pressure processing on milk coagulation properties النص الكامل
2017
Liepa, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Zagorska, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia)
Raw milk cheeses are known to have more intense and strong flavour and different texture due to natural microbiota and enzymes. Nevertheless, there are concerns about safety of these products. For microbial inactivation heat treatment of milk is used, but it can adversely affect the flavour, taste and texture of the product. Therefore, applying non-thermal technology such as high pressure processing is attracting alternative. The aim of this study was to examine the effects of high pressure treatment of cow`s milk at a wide range of pressures (400–600 MPa) on milk rennet coagulation time, curd firmness and curd yield. Processed milk samples were subjected to enzymatic coagulation using commercial rennet to determine rennet coagulation time, yield of coagulum and curd firmness. High pressure processing insignificantly influences coagulation properties of whole milk. However, the magnitude of changes depended on applied pressure. Rennet coagulation time and curd yield were significantly different (p is less than 0.05) among the pressure treated milk samples. The higher firmness of the curd form pressurized milk than that of raw or pasteurized milk, evaluated positively. The main effects of high pressure treatment in milk appeared to involve dissociation of casein micelles from the colloidal to the soluble phase. This study suggests that high pressure treatments of milk at 500 MPa or 550 MPa for 15 min may be beneficial for improving the coagulation properties of milk. These positive effects indicated that high pressure processing may have potential for new cheese varieties development.
اظهر المزيد [+] اقل [-]Effect of high pressure processing on microbial load in pork النص الكامل
2017
Sazonova, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gramatina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Fresh meat is a highly perishable product due to its biological composition as it serves as an ideal environment for the growth and propagation of microorganisms and common food-borne pathogens. High pressure processing (HPP) is a cold pasteurization treatment to extend shelf-life while preserving the sensory and nutritional characteristics of the product. The aim of this research was to evaluate the effects of HPP on the fresh porcine Musculus longissimus lumborum microbial load and related physical properties (pH, water activity aw, and moisture content). Vacuum packed meat samples were treated at 50, 100, 200, 300, 400, and 500 MPa for 1, 5, and 15 min in a high-pressure processor ISO-Lab S-FL-100-250-09-W (Stansted Fluid Power Ltd., UK). Pressure treatment above 300 MPa resulted in a significant (p is less than 0.05) decrease of total plate count. However, the studied pressurizing time had no significant effect on microbial lethality at the same pressure applied. Other important parameters such as water activity, moisture, and pH were determined as they directly affect microorganism growth and resistance to pressure. A slight increase in pork pH was observed with increased pressure. No significant changes in water activity and moisture content were observed as a result of high pressure treatment. For future researches it would be important to evaluate the dynamics of microbial growth during storing as part of cells after pressure treatment are injured and not eliminated immediately; therefore, microbial count may further decrease during cold storage.
اظهر المزيد [+] اقل [-]Effect of probiotics and herbals on health and shedding of resistant Escherichia coli in piglets النص الكامل
2017
Galina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Valdovska, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The purpose of this study was to evaluate the effect of probiotics, herbals and buckwheat bran (Fagopyrum esculentum L.) on growth, profile of blood, gut microbiota, profile of fatty acid in meat and shedding of resistant Escherichia coli (E. coli) in piglets. A total of 44 piglets (Sus scrofa domesticus) from age of day 14 to 56 were divided into 4 groups. Control received basal diet (group C), basal diet + probiotics (group P), basal diet + 3% buckwheat bran (group PB) and basal diet + 1.5% herbals (group H). No effect was observed in growth in all groups. The count of Lactobacillus spp. increased (p is less than 0.05) in jejunum in group P. In the faeces, Enterobacteriaceae decreased in the group P (p is less than 0.05) of 35 days old piglets, but Enterobacteriaceae and E. coli decreased in the group H (p is less than 0.05) of 56 days old piglets. The prevalence of resistance to at least one antibiotic class was 66.7% before and 50% after the experiment in all groups. Multidrug resistance of E. coli was not observed in 14 days old piglets, but was observed in 50% and more in all of study groups of 56 days old piglets. The fatty acid composition of Longissimus thoracis muscle had higher levels of α-linolenic acid and palmitoleic acid (p is less than 0.05), but lower level of stearic acid (p is less than 0.05) in group P. In conclusion, probiotics and herbals improved gut microbiota, fatty acid profile and affected shedding of resistant E. coli, but not growth performance.
اظهر المزيد [+] اقل [-]Clinical symptoms and sex steroid measurements in domestic ferrets (Mustela putorius furo) with Hyperadrenocorticism النص الكامل
2017
Grinblate, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilgaza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Hyperadrenocorticism (excessive adrenal production of sex steroids related to adrenocortical adenomas and carcinomas) is a common disease in neutered male and female pet ferrets (Mustela putorius furo) and causes significant morbidity. Incidence of ferret adrenal disease in Latvia is high because the majority of them are gonadectomized. The most common clinical symptoms include symmetrical alopecia and recurrence of sexual behavior. Sex steroids used to diagnose disease are estradiol, androstenedione and 17α-OH progesterone. It is mentioned that androstenedione is the most sensitive during development of the disease. The aim of this study was to sum up, evaluate and compare clinical findings and blood hormone measurements in ferrets diagnosed with hyperadrenocorticism. Forty two ferrets (n = 20 female, n = 22 male) with various clinical symptoms related to hyperadrenocorticism were included in this research. Clinical examination based on clinical symptom protocol was performed and blood samples were taken in all cases. There is a high correlation between the age of neutering and onset of clinical signs in female ferrets. In both sexes, there is no correlation between clinical signs and levels of sex steroids. In male and female group, symmetrical alopecia, pruritus, scaling and fragility of skin and lethargy are the most common findings. During this research, a ranking system (from 1 to 4) for the severity of alopecia was developed. All ferrets had one or two elevated sex steroid levels. In our research, androstenedione was elevated in 25 cases out of 42. Clinical signs and sex steroid measurements are important in diagnosing hyperadrenocorticism in ferrets.
اظهر المزيد [+] اقل [-]Influence of legumes on soil fertility in strawberry – legume intercropping النص الكامل
2017
Dane, S., Latvia Univ. of Agriculture, Jelgava (Latvia);Pure Horticultural Research Centre, Pure parish, Tukuma Municipality (Latvia) | Laugale, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lepse, L., Latvia Univ. of Agriculture, Jelgava (Latvia);Pure Horticultural Research Centre, Pure parish, Tukuma Municipality (Latvia) | Silina, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Legumes are becoming more popular in food and feed consumption. They are promoted by EU policy related to healthy lifestyle and environmental policy. Legumes can be grown in crop rotation as monocrop or in different kind of intercropping systems. It is a well-known fact that legumes play an important role in fixation of the atmospheric N, whereas their influence on other biological and chemical aspects of the soil ecosystem is only explored partially. The experimental trial was established at the Pūre Horticultural Research Centre with the aim of studying the influence of legumes on the soil properties in the intercrop with strawberries (Fragaria × ananassa Duch.). Different genotypes were included in the trial as intercrops: two local broad beans (Vicia faba var. major L.) genotypes, two pea (Pisum sativum L.) cultivars and clover (Trifolium hybridum L.). Two control treatments were included in the trial: with and without nitrogen fertilizer usage. Strawberries were planted in May of 2014 and maintained in the field for three years. Results showed that there were significant differences between treatments in soil respiration rate (SRR) and SRR dynamic throughout the experiment time. Dehydrogenase activity had similar results, though no significant differences between treatments were observed in the third year. No significant difference between treatments was found in the soil organic matter. Obtained data shows that legumes have a significant influence on the soil biological properties but not on biochemical properties. Further research needs to be carried out to determine legume influence on soil environment in more detail.
اظهر المزيد [+] اقل [-]Insight in edamame yield and quality parameters: a review النص الكامل
2017
Zeipina, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Alsina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lepse, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
Environmental conditions and climate change on a global scale affect the overall agriculture and food supply. Edamame, also called vegetable soybean is an import vegetable in the world, especially in the East Asia. China is the world’s centre for vegetable soybean production. Edamame beans are harvested before full maturity when bean pods are green and just before turning to yellow colour. Most cultivated varieties in the world are of Japanese origin. The aim of this literature survey is to give a review on history and consumption facts of edamame, as well as on the yield and quality parameters of this fresh commodity. Monographic method has been used for this review. Edamame has a high nutritional and medical value. Composition of biologically active compounds in edamame plants is dependent on climate conditions, seasonal changes, cultivar properties and maturity stage. Vegetable soybean has a long cultivation history in the world. In Europe edamame is grown, but in Latvia edamame has not been grown until now, but there is some experience in soya grain growing. Pod colour is the main external quality factor of edamame. It can be influenced by light, moisture, fertilization, variety properties, planting density and harvesting procedures. Vegetation period for edamame in most cases is reported to be between 75 and 100 days. Environmental conditions and climate change on a global scale affect the overall agriculture and food supply. Edamame, also called vegetable soybean is an import vegetable in the world, especially in the East Asia. China is the world’s centre for vegetable soybean production. Edamame beans are harvested before full maturity when bean pods are green and just before turning to yellow colour. Most cultivated varieties in the world are of Japanese origin. The aim of this literature survey is to give a review on history and consumption facts of edamame, as well as on the yield and quality parameters of this fresh commodity. Monographic method has been used for this review. Edamame has a high nutritional and medical value. Composition of biologically active compounds in edamame plants is dependent on climate conditions, seasonal changes, cultivar properties and maturity stage. Vegetable soybean has a long cultivation history in the world. In Europe edamame is grown, but in Latvia edamame has not been grown until now, but there is some experience in soya grain growing. Pod colour is the main external quality factor of edamame. It can be influenced by light, moisture, fertilization, variety properties, planting density and harvesting procedures. Vegetation period for edamame in most cases is reported to be between 75 and 100 days.
اظهر المزيد [+] اقل [-]Nitrogen fertilizer influence on winter wheat yield and yield components depending on soil tillage and forecrop النص الكامل
2017
Litke, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ruza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Wheat (Triticum aestivum) is one of the main crops grown in Latvia. Nitrogen fertilizer is one of the most important factors affecting the acquired yield and its quality. The aim of this paper is to describe the nitrogen fertilization impact on winter wheat yield and yield components under two soil tillage systems and after two forecrops. Field trials were carried out at Research and Study farm ‘Peterlauki’ of Latvia University of Agriculture (56° 30.658°C N and 23° 41.580°C E) in 2014/2015 and 2015/2016. Researched factors were (1) crop rotation (continuous wheat and wheat/oilseed rape (Brassica napus ssp. oleifera), (2) soil tillage (traditional soil tillage with mould-board ploughing at a depth of 22 – 24 cm and reduced soil tillage with disc harrowing at a depth below 10 cm), and (3) nitrogen fertilizer rate (N0 or control, N60, N90, N120(90+30), N150(90+60), N180(90+60+30), N210(90+70+50), and N240(120+60+60). Results showed that the nitrogen fertilization significantly increased winter wheat grain yield after both forecrops and in both soil tillage variants. Grain yield significantly increased until the nitrogen fertilizer rate N180. Nitrogen fertilizer significantly affected all tested yield components. Values of yield components increased enhancing N-rate of N150 – N180. The forecrop had a significant impact on wheat yield and 1000 grain weight (both increased when wheat was sown after oilseed rape). Yield and grain number per ear were significantly higher when conventional tillage was used, but number of ears per square m – when the reduced tillage was used.
اظهر المزيد [+] اقل [-]The influence of kappa-casein and beta-lactoglobulin genotypes on milk coagulation properties in Latvia dairy breed النص الكامل
2017
Petrovska, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Zagorska, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ciprovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Milk yield, composition and milk coagulation properties can be affected by kappa-casein (κ-CN) and beta-lactoglobulin (β-LG) genotypes and breed. Latvian Brown (LB) and Latvian Blue (LZ) are local dairy breeds in Latvia. These breeds are not so high-yielding than other commercial dairy breeds, besides, the number of those animals decrease each year. The aim of the research was to analyse the influence of κ-CN, β-LG and breed on milk composition and milk coagulation properties. Data were collected from 56 Latvian Brown and 26 Latvian Blue in 2016. Widespread κ-CN genotype was AA (0.593) in LB breed and AB (0.636) in LZ breed, while β-LG highest frequency was BB genotype. Significant effect was not observed on milk yield; however the highest daily milk yield was from AB κ-CN genotype (19.7 ± 1.52 kg) in LB breed. Significant differences were observed in fat content – the highest fat content accordingly κ-CN was from AA genotype in LB (46.3 ± 1.89 g kgE-1) and 45.5 ± 1.37 g kgE-1 from BB β-LG genotype in LB breed (p is less than 0.05). A lower protein content was observed from AA κ-CN genotype in LZ breed (33.8 ± 1.30 g kgE-1), while highest from BB genotype in both breeds. Curd firmness was not significantly different by genotypes and breed. Significantly shorter milk renneting time of β-LG was obtained from LB breed (14.6 ± 2.76 min, p is less than 0.05), while κ-CN genotype was not significantly affected.
اظهر المزيد [+] اقل [-]