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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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The importance of vitamin D and calcium in the human diet
Bártová, Magdaléna ; Hejtmánková, Alena (advisor) ; Michlová, Tereza (referee)
Vitamin D refers to a group of fat soluble steroids. The most important forms are
cholecalciferol occurring in foods of the animal origin and ergocalciferol of the plant origin. Human
accept them in the diet; the fatty fishes, fish liver, and some other foods like milk, eggs or yeasts are
rich resources of vitamin D. Unlike the other vitamins, the synthesis of vitamin D can also take place
in the living body. Cholecalciferol is formed in the skin from its precursor 7 - dehydrocholesterol by
the effect of UVB radiation. The conversion efficiency depends on various factors.
Two successive reaction steps are necessary for the activation of vitamin D. The first step of
hydroxylation occurs in the liver to be formed calcidiol. Calcidiol is the principal form of vitamin D in
the blood acting also as the indicator of body supplies. The second one takes place in the kidneys
where calcidiol is transformed to calcitriol. Calcitriol is assumed as the active hormonal form of
vitamin D binding to the receptor for vitamin D - VDR. The best known and the most explored
function is the effect of vitamin D on the calcium and phosphorus homeostasis. Consequently, vitamin
D also influences the proper functions of muscles and the immune system. It reduces the risk of the
cancer and cardiovascular diseases by various mechanisms as well. However, there are assumed
another effects of vitamin D on the human body, which are not fully yet understood and are the subject
for further research.
Calcium constitutes the major mineral component of bones and teeth. It is an essential nutrient
and therefore it is necessary to supply it with food. Its content in foods is various as well as its
usability from these. The major resources of calcium are milk and dairy products. Calcium is also
present in eggs, mineral waters, certain fishes and food of plant origin. Especially, the plant resources
usability of calcium is limited because of the insolubility of some calcium complexes. Calcium is
essential for the composition structure of bones and teeth. Besides of structural function, it has a main
role in the blood coagulation, neuromuscular transmission or muscle contraction.
Vitamin D has an influence on the usability of calcium because of the efficiency increase of
calcium absorption in the intestine. The lack of both micronutrients leads to skeletal diseases -
osteoporosis, osteomalacia and rickets. The adequate intake of both essential part of food, vitamin D
and calcium, is important especially for the growing children, elderly people, and pregnant and
lactating women.
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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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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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Impact of selected factors on laying hens and egg quality.
ZDICHYNEC, Martin
In accordance with the specification of the thesis I developed a methodology target program and I watched it four identical halls, which have different technology housed laying hens. In this thesis are analyzed indicators lay in the selected poultry company in the South Bohemia for the impact of housing hens, their nutrition and feeding. In the selected company enterprise on the one hand technology is used enriched cages EUROVENT - EU Big Dutchman and on the one hand technology aviary housing system used LIBRA with the Italian company of SKA.
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The adjustment of the feed ration for laying hens in order to improve the strength and the hardness of eggshells
HEINDL, Jakub
This major thesis expands the issue of the bachelor thesis "The issue of raising laying hens considering on introduction of enriched cages" and adds new knowledge relating to the topic feed rations and their influence on the final production. The theoretical part of the thesis analyses the basic theoretical concepts cohering with this topic, focused on creating a comprehensive overview of the structure and quality of the eggs, the basic ingredients in the feed rations, qualitative parameters of grapes as the modified additive provided by us and last but not least there is processed the recent overview of the current state of large-scale farmers in the Czech republic. The practical part of the thesis aims to test the effect of the proposed feed with an additive in the form of the crushed grape seeds, on the strength of the eggshell, by homogeneous samples of the breeds through from us proposed measuring instrument. Subsequently, a statistical evaluation of measured results is realized. In conclusion, the consideration is extended to the economic evaluation of costs and profits in case of the implementation of the suggested feed ration into practice in order to quantify the difference compared to the commonly used feed ration.
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Comperison quality of eggs depending on form of feeding
PROCHÁZKOVÁ, Alice
The topic of my dissertation is Comparison of the quality of eggs depending on the method of feeding. The aim of this study was to investigate whether the quality of hen eggs changes after adding crushed grape seeds in the compound feed of the hens. Grape seeds are formed as a side product during wine making processes and contain large amounts of biologically active substances and suitable acids, which can improve the feed conversion and subsequently also improve the technological properties of eggs. With processing of grape seeds the effective utilization of crop residues in vineyards comes about. The experiment was conducted in two experimental periods and in each period 100 laying hens were surveyed. They were separated into two groups an experimental and a control one. In the control group the hens were fed with a standard mixture of N2 feed and in the experimental group there was a supplement of 5 weight percent of crushed grape seeds in the compound feed. Eggs were collected daily and once every two weeks an analysis of technological properties of eggs was conducted. The results of the experiment showed that the addition of crushed grape seeds containing a biologically active substance did not have a statistically significant effect on the quality and selected technological parameters of eggs.
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Effect of food on fertility in assassin bug \kur{Platymeris biguttatus}
ZVONEK, Dalibor
This thesis was developed in order to determine whether the selected species most commonly kept feeding insects affect fertility in captive bred assassin bugs \kur{Platymeris biguttatus}. Used feeding insects were \kur{Blaptica dubia} roaches, \kur{Acheta domestica} crickets and larvae of \kur{Tenebrio molitor} bugs. The reason of using assassin bugs \kur{Platymeris biguttatus} was their popularity among breeders, their easy care needs and their superior fertility. Assassin bugs were kept in an air conditioned room with a constant temperature conditions and light regime. It has been shown that the given diet has no effect on fertility in this kind of bugs, also that breeding in groups has negative impact on fertility of this assassin bugs species. The results of this study could demonstrate the importance of proper feeding in keeping these bugs and help breeders to have better results.
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Analysis of the commercial properties of an ostrich
KULÍK, Pavel
This thesis deals with the problem of commercial properties of an African ostrich collected on farms in the Czech Republic. Literature review focuses on the history, origin, economic benefits and also the breeding conditions. This work evaluates the utility of selected properties of ostrich farms in the Czech Republic. The values obtained were well described and evaluated by appropriate methods. Egg-laying farms was observed in the range from 15 to 50 pieces (mean 29.07 pieces), the weight of eggs ranged from 1.22 to 1.89 kg (mean 1.51 kg), fertilization of eggs were in the range from 54.55?86.00% (mean 76.36%) and a hatching rate was in the range of 31.82?52.77% (mean 44.61%). Weight of meat obtained from slaughter ostrich ranged from 30 to 50 kg (mean 39.74 kg), the skin area was in the range from 1.10 to 1.50 m2 (mean 1,34 m2) and the production of feathers was from 1.36 to 1.50 kg.
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Environmental aspects of eggs production from point of view of greenhouse gasses emissions
KALKUŠ, Václav
The aim of the study is to compare poultry farming focused on either conventional or organic egg production. Detailed information has been gathered in particular organizations by the means of questionnaires and provided technical literature. We have concentrated on the monitoring of the emission impact on the environment, caused especially by feed material consumption, electricity consumption and farm dung management. Based on the gathered data the emission burden was calculated by the means of Ecoinvent database using CO2 equivalent. We have compared the individual systems of management and evaluated greenhouse gasses production. The main target of the thesis was to find out whether the production of organic eggs has smaller impact on the environment than the conventional one.
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