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Effect of fish feeds with high vegetable oil and low fish oil content on the growth performance and innate immune system of common carp (preliminary results)
7-12Views:81Fish meal and fish oil are very important components of fish feeds used by aquaculture. They contain poly-unsaturated fatty acids, which are essential nutrients both for fish and human nutrition. However, sources of fish meal and fish oil are limited, there is a need for new feed components to supply the increasing fish production and the increasing demand for fish feed. The aim of AQUAMAX project, supported by the European Union is to replace the fish meal and fish oil with vegetable oils. As a participant of this project, group of immunology in Research
Institute for Fisheries, Aquaculture and Irrigation (HAKI) examined the effect of three different fish feeds on the growth performance, innate immune response and resistance against Aeromonas hydrophila infection of common carp in an in vivo experiment. Fish feed supplemented with Camelina oil, but still containing fish oil significantly increased growth performance of experimental fish and their resistance against the infection. Fish feed containing linseed oil only did not enhance the growth performance, and it had a negative effect on resistance against infection. Based on the experimental results it can be concluded that fish oil used in fish feeds cannot be replaced effectively with vegetable oils, but can be supplemented with them. -
Parameter optimization of an inductively coupled plasma mass spectrometer for measuring arsenic and selenium
81-85Views:147In the last decades, an increased interest has evolved in arsenic and selenium. The aim is to understand the environmental, agricultural and biological roles of these elements. In the case of arsenic, the major reasons are the relatively high concentration of arsenic in marine biota (mg kg-1) and the arsenic contaminated drinking water bases of some Asian countries, as well as Hungary. The toxicity of higher level selenium content is also known; nevertheless, selenium is essential for several biological functions. Considering its essentialness, in our country, the insufficient selenium intake rate causes a lack of selenium. Measuring the concentrations of these elements provides crucial, but unsatisfactory information, as the speciation, i.e. the form of an element presented in a sample is also required.
In both cases, the most suitable method to determine concentration is inductively coupled plasma mass spectrometry (ICP-MS). Our objective was to optimize the variable parameters of the ICP-MS to attain the lowest (the best) detection limit. For this purpose, we investigated the effect of parameter change on net signal intensity and relative signal intensity. With the optimized parameter settings, the limits of detection for arsenic and selenium were determined, which are 0,032 ng dm-3 for arsenic, and 0,097 ng dm-3 for selenium. -
Study of some physiologic properties of different genotype sweet corn hybrids
105-110Views:98The effect of nutrient-supply (control, N120+PK) and two different genotypes on the physiologic properties of sweet corn has been investigated in the crop-year of 2011 on chernozem soil in the Hajdúság region. The experiments were carried out at the Experimental Station of the University of Debrecen in Debrecen-Látókép. The experiment was sewn in two different sowing times: the 21st April can be considered as an early, while the 19th May as a late sowing time. The two involved hybrids were Jumbo and Enterprise. The applied plant density was 65 000 plants per hectare.
Our aim with this experiment was to study the plant production, just as the main affecting factors of its development and dynamics, like nutrient-supply and genotypes. We aimed to study and analyse the relationships between these factors and plant production. In this study following parameters were measured and calculated: photosynthetic activity, chlorophyll-content (SPAD-value), leaf area index (LAI) and leaf area duration (LAD). Regarding the analysis of photosynthetic activity values no obvious relationship between the measured values and the applied hybrids, just as nutrient-supply has been revealed.
Analysing the SPAD-values it can be stated that the chlorophyll-content of the measured leaves showed an increasing tendency due to the nutrient-supply. The highest values have been measured in the intensive cob development phase of the early sowing time plots.
Regarding the LAI-values we have found significant differences between the fertilizer treatments in both sowing time treatments. In case of the leaf area duration values – that is derived from the LAI values – nutrient-supply has positively affected the duration of the assimilation area. -
Agronomical and economic evaluation of various cultivation systems on meadow soil
103-106Views:108The requirements and objectives of cultivation are in constant change. There are different cultivation aims if the objective is soil protection, the prevention of its moisture content or on areas with different precipitation supply or production site endowments. Based on the experimental database of the Institute for Land Utilisation, Regional Development and Technology of the University of Debrecen, Centre for Agricultural and Applied Economic Sciences and the KITE Plc., the various cultivation systems in Hajdú-Bihar country were examined with maize as indicator plant. The sample area can be found in the outskirts of Biharnagybajom on meadow soil. On the examined plot, spring strip basic cultivation, loosening and autumn ploughing were applied on 15-15-15 ha, respectively. At the time of taking undisturbed soil samples, soil conductivity measurements were also performed with a Penetronik penetrometer. Undisturbed soil samples were taken from each treatment before sowing (on 5th April 2012). The yield obtained in the strip cultivation treatment increased that of the ploughing and the loosening technology. The economic indexes are the most favourable in the strip cultivation.
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The relationship between the nutrient supply and the yield of maize hybrids with different genetic traits on chernozem soil in variant years
27-31Views:189The experiments were set on lime-coated chernozem soil in 2013 and in 2014, in our study four hybrids were included with different FAO number. We studied the effect of NPK fertilization and row spacing on the yield. The fertilizer doses were based on a 25-year longterm experiment. Compared to control, the N40 +PK treatment has also achieved a significant yield increase, although some hybrids responsed with yield loss to the increasing fertilizer doses; this effect was observed especially in 2014. The majority of hybrids reached higher yields in both years using the 50 cm row spacing. The water release of hybrids was measured weekly during the maturation, at the same time points. The rainy September slowed ripening and the water release of the hybrids in 2013, so the grain wet content at harvest showed higher values. The moisture contents were increased for some hybrids, in spite of the positive and favorable dynamic of water loss.