In the study 3 experiments were carried out. The objective of the first experiment was to evaluate performance of laying hens, quality of air in poultry house, and microbial contamination of the eggshell in laying hens kept under blue, green, red, and yellow light colour in enriched cages. The laying performance characteristics (hen-day egg production, mortality, and egg weight) were not affected by light colour. Similarly, microbial contamination of the air was not significantly different related to the light colour. There were significant interactions in eggshell contamination between cage floor and light colour in Escherichia coli and Enterococcus. The highest number of Escherichia coli was detected in eggs from hens housed in the middle floor given yellow light and the lowest values on the upper floor also under yellow light colour. Similar results were observed in Enterococcus. The results of our study indicate that the light colour has a minor effect on microbial contamination but the significant influence was in the floor position. The highest microbial egg contamination was found on eggs from the middle floor.
In the second experiment, the effect of housing system (conventional cage, litter, aviary) and feed calcium content (3,0 and 3,5%) on laying performance characteristics, technological quality of eggs, microbial contamination of the eggshell and egg content during storage was evaluated. The significant interaction between housing system and feed calcium content was found in egg weight, eggshell strength, eggshell percentage, eggshell weight, Haugh units and albumen index. The housing system affected egg production, feed intake, egg weight and some characteristics of eggshell quality. From characteristics of eggshell quality the feed calcium content affected only eggshell strength and eggshell percentage. The significant interaction between housing system and storage time was found in contamination of eggshell by total number of microorganisms. The housing system affected also contamination of the eggshell where higher number of Escherichia coli and total number of microorganisms were in eggs from litter. Higher penetration of all monitored species of microorganisms on the eggshell membranes was 2nd and 7th day of storage in the group with 3.5% of calcium in the feed mixture in eggs from the litter. This could be associated with lower quality of eggshell in this type of housing.
In the experiment 3, the effect of different housing system (enriched cage, free range) on technological quality of eggs, microbial contamination of the eggshell, egg content and concentration of protein in albumen during storage was observed. The housing system affected all characteristics of eggshell quality with higher values in cage system. Higher number of pores in eggshell was found in free range. The important relationship between housing system and storage time was indicated in Haugh unit, albumen index, pH albumen and yolk index. The values for characteristics quality of albumen and yolk were better in eggs from cages. Their quality during storage decreased faster in alternative housing systems. There was detected interaction between housing system and storage time also in Escherichia coli, Enterococcus and total number of microorganisms. The highest microbial contamination in fresh eggs was found in free range. The number of microorganisms with storage time significantly decreased faster in eggs from cage system. The penetration of Escherichia coli and total number of microorganisms in albumen was lower in eggs from cage compared to free range. The significant effect of housing system was found in concentration of lysozyme in albumen with higher values in egg from free range. It is obvious that a better quality of the eggs is in the cage housing system. The eggs from this type of housing also remain during storage for longer time in better quality compared with alternative housing systems.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:259644 |
| Date | January 2016 |
| Creators | Vlčková, Jana |
| Contributors | Tůmová, Eva, Skřivanová, Eva |
| Publisher | Česká zemědělská univerzita v Praze |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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