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Development of quality indicators of hens eggs from different types of breeding over time
ŠTĚPÁN, Stanislav
This thesis dealt with the determination of quality indicators of hen eggs from diffe-rent types of breeding - free range (domestic), litter house and enriched cage bree-ding, their comparison with each other and with our own results from 2021. 10 samples from each breeding were evaluated. There was no significant difference (p>0.05) between the eggs from each type of rearing in terms of volume, shape index, air bubble height, solid white index, Haugh units and yolk index. The shell was intact in all samples. There were differences in egg weight (p<0.001) and shell thickness (p<0.05). When compared with the 2021 results, the largest differences were in the litter-reared eggs, which were different in all parameters except shape index. For free-range (home-reared) eggs, there were differences in weight, shell thickness (p<0.001) and egg shape index (p<0.05). Eggs from enriched cage rearing differed in weight (p<0.001) and yolk index (p<0.01).
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Variability of lipid classes and fatty acid composition during over ripening of oocytes from tench (\kur{Tinca tinca})
KRZYŚKÓW, Anna
In this project, the eggs of tench (Tinca tinca) were used for the evaluation of changes in fatty acid (FA) composition and lipid classes during in vitro ova ageing until the occurrence of over-ripening. Stripped ova of 6 females were collected separately and stored in sterile cell culture plates in an incubator at 20 °C for up to 24 hours post stripping (HPS). Stored ova were fertilized at 0, 2, 4, 6, 8, 10 and 24 HPS. Egg eyeing and hatching rates were assessed as indices of egg quality. Upon fertilization at each HPS, samples were taken separately frozen in liquid nitrogen and stored at -80°C till further analyses. Differences in the FA and lipid composition and embryo survival rates at the different fertilization times post-stripping were evaluated. The lipid fraction was extracted from the oocytes according to Hara and Radin (1978). The lipid content of the samples was determined gravimetrically from total extracted lipid. The FA were then analysed with a gas chromatograph equipped with a flame ionisation detector and PVT injector. The peaks were identified by comparing their retention times with those of authentic standards. Major lipid classes and the phospholipid classes were separated according to (Olsen and Henderson, 1989). Quantitative analysis of the separated lipid- and phospholipid classes was done by scanning the plates after derivatisation with a CAMAG TLC Scanner 3 (Camag, Switzerland). Identification of the lipid classes was performed by comparison with authentic standards applied on the same plate. In present study no significant changes were observed in lipid content and composition during storage of eggs until over-ripening. As well FA composition did not change over time indicating another reason of deterioration of oocyte quality than the proposed lipid oxidation. However individual fishes in this study showed much different fertilization rates that corresponded with their levels of cholesterol and triacylglycerols in minor degree.
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Influence of moulting on economy of layers breeding
AMEROVÁ, Veronika
Poultry breeding presents an important part of agricultural production. Its importance is growing in relation with globalization of market. Egg production is a very important part of that. After a period of stable growth of eggs production during 80{\crq}s and 90{\crq}s of last century, we can currently observe stagnation and decline of the production. Import of consumption eggs for dumping prices and very strict and difficult conditions for eggs production business in the frame of EU, seriously endanger future existence of eggs producers is the Czech Republic. The intention of each breeder of poultry for eggs production is to minimize the costs and maximize the production. An important tool for reaching this target is using the poultry for maximal possible period of time. That means for the second yielding cycle after molting. Although the yield of eggs during the second cycle is less frequent, the eggs are bigger and heavier. This method ensures costs savings in acquisition of new poultry. Any improvements during any faze of the eggs production, that would bring cost savings is highly appreciated. There was done a comparison of eggs production under the standard method and also under the method of using controlled molting and second yielding cycle. The project took three years. The key area of comparison was the ratio of expenses to production unit. ISA Brown poultry was used for the project. The objective was to verify the influence of molting to the efficiency of poultry in the second yielding cycle. I have focused on the economical results, such as average efficiency, costs intensity and realization price of eggs. The conclusion for the project is following: Controlled molting of layers is important economical tool to production costs savings. During the period of the project economical result (profit) achieved was higher for 617.414 Czk at the group of molted poultry, compared to the standard yielding group. The reasons are on the costs side, the most significant savings are: i) Acquisition of poultry (two times during the period of 3 years) ii) Lower costs of fodder iii) Costs of disinfection of breeding halls
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