The aim of this review paper is to update, present and discuss the current research findings from recent studies regarding the efficacy of organic sources of microelements in poultry nutrition. Most intensively evaluated in poultry feeding studies have been organic forms, i.e., proteinates and amino acids complexes and chelates, of such microelements as Zn, Mn and Cu. The results of these studies are not always consistent, particularly in regard to performance indices; however, the majority of the findings from recent experiments indicate that organic minerals are an effective source of microelements, and can replace, with some advantages, inorganic forms of minerals in poultry diets. One of the main benefits is the option to use lower inclusion levels of minerals added in organic forms, which may reduce the mineral content in the resulting poultry excreta.

Cottonseed meal (CSM) is a by-product of the oil industry, i.e. oil extraction from cotton seeds. It is a rich source of protein (30 to 50% dry matter), characterised by a high concentration of amino acids. However, a relatively low concentration of lysine restricts the quality of protein in CSM. Its use as a feed material in poultry nutrition is limited mainly by free gossypol presence, as well as high variability in nutrient concentration. Gossypol is a polyphenolic compound reducing protein digestibility by inhibition of pepsin and trypsin activity in the intestine and binding iron in the diet. High dietary levels of CSM can negatively affect growth performance and egg production and quality. Dietary treatments including increased iron and lysine supplementation can increase the usefulness of CSM in poultry nutrition by alleviating the toxic effect of gossypol. The results of recent experiments on the use of CSM meal as a feed material for poultry are discussed in this review article. Based on the results presented, cottonseed meal is an acceptable ingredient of poultry diets and could be safely fed at a 10-15% dietary level, partially replacing - in a cost effective way - soybean meal.

The aim of this review is to discuss the use of microalgae as a feed ingredient in poultry nutrition. Microalgae are unicellular, photosynthetic aquatic plants. They are introduced to poultry diets mainly as a rich source of n-3 long chain polyunsaturated fatty acids, including docohexaenoic and eicosapentaenoic acid, but they can also serve as a protein, microelement, vitamin and antioxidants source, as well as a pigmentation agent for skin and egg yolks. The majority of experiments have shown that microalgae, mainly Spirulina and Chlorella sourced as a defatted biomass from biofuel production, can be successfully used as a feed ingredient in poultry nutrition. They can have beneficial effects on meat and egg quality, i.e. via an increased concentration of n-3 polyunsaturated fatty acids and carotenoids, and in regards to performance indices and immune function. Positive results were obtained when fresh microalgae biomass was used to replace antibiotic growth promoters in poultry diets. In conclusion, because of their chemical composition, microalgae can be efficiently used in poultry nutrition to enhance the pigmentation and nutritional value of meat and eggs, as well as partial replacement of conventional dietary protein sources.

A high content of non-starch polysaccharides (NSP), namely arabinoxylans (AX), in rye is a reason for the potential adverse effect of this grain on intestinal functions, gut microflora, absorption of nutrients and performance indices. As such, the use of rye grain in intensively produced poultry diets is limited. However, recently developed new types of hybrid rye are characterised not only by increased yield potential, resistance to fungus and pests and low production costs, but also the content of antinutritive substances may be reduced in these varieties. The aim of this paper is to discuss the mechanisms of NSP effects in the digestive tract, as well as to review the results of recent studies on the use of rye in poultry nutrition. Based on the literature data, it can be concluded that the use of new hybrid rye varieties with decreased NSP concentration and NSP-hydrolising enzymes may be a way of increasing the share of rye grain in poultry diets.