Studies were carried out to determine the effect of additive iron-glycine chelate on the production performance, slaughter yield, mineral deposition in the liver and the metabolic blood panel in broiler chickens. A total of 250 one-day-old Ross 308 chicks were allotted into five groups with five replicates of 10 birds each. Diets were supplemented with the organic form iron (Fe-Gly at the rate of 25%, 50% or 100% of the total requirements of the elements) and inorganic Fe (FeSO4 at the rate of 50% or 100%). In the experiment, iron was added to the premix (containing no Fe) in an amount of 40 or 20 mg per kg of basal diet, in groups I and II, in the form of FeSO4 , and in an amount of 40, 20 or 10 mg per kg of basal diet, in groups III, IV and V, in the form of Fe-Gly. The study covering the period from the first to the 42nd day of breeding revealed that the production performance and slaughter yield were not dependent on the form and amount of added Fe. In the experimental groups with the addition of Fe-Gly of 20 or 10 mg/kg, there were no deaths of chickens during the whole fattening period. As a result, introducing an organic form of iron covering 50% and 25% of the birds' requirement increased the effectiveness of chicken fattening (European Efficiency Index) (p < 0.01). An organic Fe compound (40, 20 or 10 mg/kg) added to mixtures contributed to significant changes in the level of biochemical and haematological indicators in blood. The study demonstrated that an addition of Fe-Gly to mixtures for broilers can be fully effective in terms of production and health performance even if the suggested requirement for this element is 50% or 25% covered.

-The paper aimed to evaluate the level of development of agriculture in 25 member states of the European Union (EU) in 2010-2013. The analysis was carried out using the development model proposed by Hellwig, which enabled the calculation of a single synthetic aggregate measure based on the characteristics of agriculture in respective countries. This made it possible to compare the analysed member states, thus providing the basis for allocating them to uniform groups characterised by a similar level of agricultural development. The results indicate that the Netherlands and Denmark are the countries with the highest level of agricultural development. The studies also show that the worst level of development in the ranking is presented primarily by the member states that acceded to the EU in 2004 and later, with agriculture in Slovakia and the Czech Republic being an exception. The diversification of the values of synthetic measure in respective member states points to a considerable diversification of agricultural development within the EU, which is determined both by the production potential and the effectiveness of its utilisation.

The aim of the study was to determine the influence of Cu-glycine chelate on the chemical composition of the liver and blood parameters of broiler chickens. A total of 250 one-day-old Ross 308 male chicks were allotted into 5 groups with 5 replicates of 10 birds each. Rearing of birds lasted 42 days. In the experiment Cu was added to the premix in the form of CuSO4 (16 mg, 8 mg Cu), and in the form of Cu glycine chelate (16 mg, 8 mg, 4 mg Cu). The parameters in the chickens’ blood remained within the range of physiological norms when lower levels of the analyzed elements were added. Adding lower levels of Cu (8 or 4 mg kg-1) in comparison with the recommended doses (16 mg kg-1) for broilers, in the form of highly assimilable organic sources, did not reduce the content of minerals Cu, Fe, and Zn in the chickens’ liver, but reduced the faecal Fe, Cu and Zn concentrations compared to CuSO4.

This study has been carried out in order to determine the effect of increasingly intensive fertilization with potassium, applied in combination with nitrogen, on the content of trace elements in soil after the harvest of maize (Zea mays L.). The soil content of trace elements depended on the fertilization with potassium and nitrogen. Potassium fertilization had a stronger effect on the content of trace elements in the pots fertilized with the lower nitrogen dose (130 mg N kg−1 of soil). The increasing doses of potassium led to a higher soil content of zinc (Zn), and especially of nickel (Ni). The impact of potassium fertilization on the content of the remaining trace elements in the soil was less unambiguous, and depended on the dose of potassium and nitrogen fertilization. Nitrogen fertilization resulted in a higher soil content of manganese (Mn), chromium (Cr), nickel (Ni) and cadmium (Cd), as well as a decreased soil content of lead (Pb). It needs to be underlined that changes in the soil content of Ni, Cd, and Pb, effected by nitrogen fertilization, were larger than in the cases of the other trace elements. The influence of potassium and nitrogen fertilization did not result in exceeding the current threshold amounts of trace elements set for agriculturally used soil. An increase in the contents of some trace elements in soil is beneficial from an agricultural point of view. Some of these elements are necessary for the correct growth and development of arable plants.

The aim of the publication is to identify and evaluate the factors determining the choice of organic food products, establish links between them and decide which factors determining consumer choices on the dairy products market are the main. The analyses were based on the results of a survey conducted in 2016 on a group of 358 students. In the selection process, targeted selection methods were used. The study was carried out using the CAWI and the PAPI methods. The study uses methods of statistical analysis, including a comparative analysis of the behaviour of buyers and non-buyers of organic products and factor analysis to detect internal interdependencies between factors shaping purchasing decisions of buyers. Based on the analysis, it can be concluded that the most important factors taken into consideration when choosing organic food on the dairy market are related to the characteristics of the products. According to the surveyed buyers, an organic product is a product with a specific composition, fresh and without preservatives. The remaining factors are marketing communication, sales activation and “guarantee” of quality and healthiness of products in the form of certificates, markings and product brands.