Razvoj tehnoloških postupaka u cilju prevencije nastanka tabanskih lezija brojlerskih pilića / Development of technological processes in order to prevent the occurrence of footpad lesions in broiler chickens

Within this dissertation, the results of various technological processes are shown in order to prevent the occurrence of damage to the foot pads of broiler chickens. The study was conducted in four trials, one in which we investigated the physical - chemical and hygroscopic properties of materials that can be used as litter, as well as three biological trials which were aimed to examine the influence of various factors on the damage to the foot pads in broiler chickens. The objective of the biological experiments was to answer the question whether the various treatments of litters, usage of different preparations and nutrition can prevent occurrence of foot lesions in broiler chickens. In addition, the aim of this experiment was to determine how the applied technology affects performance of broiler chickens. Among physical properties of materials that can be used as litter in fatting broilers, absorption and release of water were investigate, and among chemical properties there were content of dry matter, crude fiber content as well as individual fractions (NDF, ADF, hemicelluloses, cellulose and lignin). Biological experiments were conducted in the facilities of experimental farm (micro experiment) and in production conditions (macro experiment). In biological experiments wheat straw was used as litter and treatments which attempted to improve its characteristics were chopping and addition of microbial-enzyme preparation (Micropan Complex®) and lignin. Feeding influence on damage to the foot pad was tested in a biological experiment, by feeding broilers with reduced energy diet and by adding enzymes that improve digestion. As a result of the impact of the above mentioned treatments there were tested the litter quality (moisture, pH and ammonia emissions), production parameters in fattening broilers (body weight, feed consumption, conversion, mortality and production index), the behavior of broilers, as well as the onset and degree of damage to the foot pads. Assessment of the damage to the foot pads was done macroscopically (on a scale from 0-3, and according to the affected area) and microscopically, by histological analysis of skin of foot pads. Test results of physic-chemical characteristics of different materials indicate that wheat straw absorbs large amounts of water, due to the low content of NDF it releases water slowly and consequently represents a bad choice for a litter in terms of damage to the foot pads. However, the results showed that chopping straw as a technological procedure may influence the onset and degree of damage to the foot pads, but it also leads to an increase in body weight of broilers as well as changes in their behavior. Addition of microbial-enzyme preparation leads to a decrease in the occurrence and level of damage to the foot pads in broilers grown on both chopped and unchopped straw. The results have also shown that, under production conditions, using lignin in the unchopped straw litter it can reduce the damage to the foot pads. The use of mixtures containing a reduced amount of energy with the use of the enzyme leads to prevention in terms of occurrence of foot lesions, without significant impact on performance. Histological analysis of foot pads have showed that the grading system that is based on the affected area of foot pads in accordance with the extent and severity of damage of the skin of foot pads and that it can represent a model for the assessment of standards on the slaughter line. Based on the results of this dissertation it can be concluded that the applied technological procedures can significantly influence the prevention of damage to the foot pads, with no negative impact on production results in fattening broilers.