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Reologické vlastnosti žloutků slepičích vajec v průběhu skladování
Pavková, Lucie
The thesis deals with the influence of storage time on particular physical and rheolo-gical properties of a yolk of chicken eggs. Monitored eggs were stored at 6 °C for 8 weeks. The thesis describes the influence of storage time on physical characteristics of a whole egg, such as weight and shape index. As expected, the weight loss of chicken eggs was demonstrated during eight weeks storing. Egg yolk (colour, height, width, weight, index and density) was also described and evaluated in detail. According to our estimates, there are no significant changes in weight during yolk storing. But yolk index is distinctly decreased. During the final part of monitoring rheological properties were evaluated - apparent viscosity, time dependence of viscosity and dependence of shear stress on the shear rate (flow curves). The experiments have proved Newtonian behaviour of egg yolk throughout the storage. The storage time has also clear impact on flow properties of yolk. The results of each experiment were modelled using the power law (Ostwald-de Waele) model.
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Vývoj spotřebitelských preferencí na trhu vajec v ČR
Němcová, Monika
The Bachelor Thesis deals with what are the consumer preferences on the eggs market. By way of introduction discusses the agricultural fair, specifics of demand and also selected commodity, which means eggs. Eggs are very important food in the nutrition and so are parts of a diet of most people. The aim of this thesis is to find out what information is of interest to consumers when buying eggs. These information is get through questionnaire survey and is focused on basic characteristics, such a price, colour of shell, or whether information mentioned on wraps are sufficient for the consumer sufficient, or what extra information would be welcomed.
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Změny mikrobiální kontaminace vajec v průběhu skladování
Zemanová, Aneta
This masters thesis deals of microbial contamination of chicken eggs in storage. Test samples were tracked for the following microbial indicators: Total Viable Count (TVC), bacteria of the Enterobacteriaceae family, bacteria of the Enterococcus genus, psychrotrophic microorganisms, yeasts and molds. Microbial analysis was made for eggs acquired from market chains, originating from three different farming environments: enriched cages, cage-free and free range. Samples were stored in three different temperature environments: refrigerated at 5 °C for the whole storage period, stored in a thermostated box at 28 °C for the whole storage period and alternating between 5 °C and 28 °C temperature environments with one week storage periods each. The analysis of acquired test samples shows that TVC did not change significantly between different farming environments and storage temperature environments. Cage-free eggs show increasing TVC in long time storage (21 days). Cage-free and free range eggs also show higher count for Enterobacteriaceae. Enterobacteriaceae counts show significant differences between samples stored at constant 28 °C and alternating temperatures. Lowest microorganism count for bacteria of the Enterobacteriaceae family was observed at alternating temperatures. Long time storage resulted in elevated Enterobacteriaceae count in cage-free eggs. Presence of Enterococcus, psychotrophic microorganism and molds was detected in a low number of samples.
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Comparison of qualitative indicators of hen's eggs from different types of feeding
ŠTĚPÁN, Stanislav
The presented bachelor thesis dealt with the comparison of qualitative indicators of hen's eggs from different types of breeding. Samples from cage farming production system, indoor housing systém and free-range home breeding were used for comparison. Ten eggs from each type were used. The following qualitative indicators were evaluated and compared - egg weight, shell integrity, air cell height, shape indices (shape index and egg index), occurrence of blood and meat spots, solid egg white and yolk index, egg quality expressed in Haugh units and shell thickness. The eggs from the individual types of breeding were similar in shape, but diffe-red the most in size and weight, the weight was measured from 49 to 91 g. Two samples had a damaged shell. The height of the air cell ranged from 2 to 4 mm. The values of the solid protein index ranged from 0.061 to 0.156 and the yolk index ranged from 0.39 to 0.51. Haugh units ranged from 74 to 107. The shell thickness was between 0.37 and 0.47 mm. All results were in or near the average.
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Vitamin D blood level and its relationship to recurrent childhood diseases
HAVLOVÁ, Adéla
"Vitamin D blood level, factors that affect it, and its relationship to reccurent infections" is topic repeatedly discussed in domestic and foreign literature. This topic is a multidisciplinary issue, but it mainly relates to nutrition and sun exposure. The aim of this study is to map relationship of vitamin blood levels in relation to diseases of the respiratory system, vitamin D suplementation, recurrent infections, usage of sunscreen with a protective factor, nutrition and outdoor stay in winter months. The study was conducted on a research sample of preschool children. Two sets of data were used to evaluate objectives and research questions. The first research group consisted of 48 children and had 2 groups. The first group of 21 children was established in the Waldorf kindergarten in Rudolfov and the second group of 17 children was created in a non-state medical facility in Trebon. The first research consisted of 48 children who were tested on vitamin D blood level and filled survey questionnaire. The second research consisted of 61 children who were tested on vitamin D blood level in a non-state medical facility. Some results of this study are contradictory because of inadequate methodology. Positive results have been shown with vitamin D supplementation, higher consumption of liver, eggs and daily intake of vegetable oils.
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Kuřecí embrya jako inkubátor pro pomnožení parazitů rodu Cryptosporidium
SCHULZOVÁ, Tereza
This study aimed to determine the extent to which infection at the embryo stage can enhance the propagation of Cryptosporidium oocysts in chickens. Nine-day-old chicken embryos and one-day-old chickens were experimentally infected with different doses of Cryptosporidium baileyi and Cryptosporidium parvum oocysts. Post hatching, all chickens had demonstrable infections, and the infection dose had no effect on the course of infection. Chickens infected as embryos shed oocysts immediately after hatching and, over the course of the infection, they shed significantly more oocysts than infected oneday-old chickens. In chickens infected as embryos, C. baileyi was found in all organs except the brain, with highest infections in the trachea and oesophagus, and C. parvum was found only in the gastrointestinal tract and trachea, with highest infections in the gut and cloaca. In one-day-old infected chickens, C. baileyi was found only in the gastrointestinal tract and trachea, with highest infections in the gut. Chickens infected as embryos with C. baileyi died within 16 days of hatching. All other chickens cleared the infection within 13-25 days. Based on these findings, infection of chicken embryos could serve as a cost effective and simple model for the propagation of Cryptosporidium spp.
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Hatching synchrony in birds
Tippeltová, Zuzana ; Hořák, David (advisor) ; Riegert, Jan (referee)
This bachelor thesis is about hatching synchrony in birds. Generally, among birds there are two types of hatching - asynchronous and synchronous- and the type of hatching is primarily determined by the time of the onset of incubation. In many bird species, including most precocial ones, incubation does not begin until the last egg has been laid, which results in hatching of all the eggs within a few hours. In synchronously-hatched broods, all the chicks are about the same age. Thus no single individual has an advantage in size or strength over any of its siblings in the nest. The survival probability is then similar for all chicks which maximizes number of fledglings under favourable condition. In contrast many species of birds begin to incubate as soon as the first eggs is laid and hatch their eggs asynchronously over a period of days or weeks, handicapping last-hatched chicks with an age and size disadvantage. Many hypotheses have been proposed to explain why female birds start to incubate before clutch completion and some of those suggest that asynchronous hatching is a parental strategy for raising the largest number of offspring that food resources will allow when the abundance of food for the chicks cannot be predicted at the time that eggs are laid. The selective pressures leading to the evolution of...
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Differentiation of different types of eggs by mass spectrometry
Švárová, Markéta ; Kučková, Štěpánka (advisor) ; Rusek, Martin (referee)
The aim of the diploma thesis was to distinguish bird species based on the expected different protein composition of eggs and their individual components using mass spectrometry. The obtained results could be possibly used to identify the animal origin of egg materials used in works of art. For the research, components of the eggs (yolk, egg white and their mixture) of nine available bird species were collected and dried - pheasant (Phasianus colchicus), domestic goose (Anser anser domesticus), domestic duck (Anas platyrhynchos domesticus), muscovy duck (Cairina moschata), chicken (Gallus gallus f. domestica) - four different specimens, Japanese quail (Coturnix japonica), pampas rhea (Rhea americana), red ore (Alectoris rufa), speckled guinea fowl (Numida meleagris). The samples were digested by the enzyme trypsin and prepared using ZIP-TIP for the next measurements by MALDI-TOF (Matrix-Assisted Laser Desorption / Ionization - Time of Flight) mass spectrometry. The obtained data were evaluated by Principal Component Analysis (PCA). The used method showed that the most bird species can be distinguished by yolks (with an approximately 95% success rate) and more than half of the species by egg white proteins (success rate 83%) and by the egg white and yolk mixtures (success rate 80%). Two samples of...
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Variability of the domestic chicken breeds in selected immunological traits of hen and egg
Bílková, Barbora ; Vinkler, Michal (advisor) ; Plachý, Jiří (referee) ; Trefil, Pavel (referee)
The avian immune system is a complex system of defence mechanisms that protect bird hosts against threats from ubiquitous pathogens. According to the co-evolutionary models, variability in immune traits of hosts is the key component providing ability to adapt and enhance their defence mechanisms in presence of constant selective pathogen pressure. Domestic chicken (Gallus gallus f. domestica) is used as a model organism in avian biology and also is one of the most important food-producing animals, not only for their meat but also for the egg production. Unfortunately, in research usually only inbred chicken lines are used and modern poultry husbandry is tight with unilateral breeding towards highly productive breeds. Those approaches decrease intra-population polymorphism in chickens. However, especially in case of farm animals, searching and extending the pool of immune variability and enhancing pathogen resistance is crucial for sustaining healthy and biologically secure populations and their products. Morphologically highly distinct traditional chicken breeds, which have evolved for hundreds years under different selective pressures, may represent this desirable immunological variability. In my thesis I described variability in chosen immunological traits, haematological parameters and proteomic...
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Zkrmování pšenice s vyšším obsahem anthokyanů u nosnic v závěru snášky
Trněná, Iva
The aim of this diploma thesis was to evaluate the influence of feeding of wheat with higher content of anthocyanins in laying hens at the end of the laying cycle compared to feeding common wheat without anthocyanins. The measured parameters included hen weight, feed consumption, laying, weight and quality of eggs and biochemical profile of hen's blood. 30 hens of the Bowans Brown hybrid combination were used in the experiment at 69 weeks of age. Layers were divided into two groups of 15 pieces. The first group was control, fed with a common wheat variety Bohemia with low anthocyanins and the second group was experimental - fed with RU 687-12 wheat colored wheat with high anthocyanin content. In the experiment, the egg laying, feed consumption, animal weight, and egg quality were evaluated in laying hens. At the end of the experiment, blood was taken for biochemical examination. The results of both groups were compared between each other. The results of the statistical assessment show that the feeding of wheat RU 687-12 has significantly influenced the feed and feed consumption, which was higher than in the experimental group. However, the hen eggs of the experimental group had a significantly lower weight. However, the total egg production was significantly higher in the experimental group (P = 0.04). Egg quality was found to be significantly higher in yolk and a higher weight of yolk, but also a lower proportion of white egg in the experimental group. Biochemical analysis of blood showed a higher blood albumin concentration in the blood plasma of the experimental group. The other monitored parameters did not differ significantly. Based on the results of the experiment, we can state that the feeding of wheat with a higher proportion of anthocyanins had a positive effect on the performance of the laying hens, expressed by the number of eggs, the production of egg mass and the higher proportion of yolk.
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