Commercial laying hens are heavily selected for increased egg production, but little selection has occurred for resistance to extreme temperatures. The objective of the experiment was to determine the effects of a daily cyclic heat stress (HS) on performance, body temperature, egg quality, nitrogen corrected apparent metabolizable energy, and blood chemistry in laying hens at acute and chronic time points. In total, 407 pure line laying hen pullets (18 wk) were sourced from Hy-Line International and housed individually for the duration of the experiment. Feed intake, egg production, and body weights were significantly decreased while egg weight and feed efficiency increased due to HS exposure. All egg quality parameters except yolk weight were decreased by HS exposure, including Haugh unit, eggshell and albumen weights. Egg yolk weights were increased over the first 2 wk of HS before falling. Blood chemistry was affected by HS resulting in respiratory alkalosis likely caused by increased respiration and evaporative cooling. There was a decrease in the PCO2, an increase in pH and a reduction in iCa in the blood within 4 to 6 hours of HS when compared to pre-HS levels. The data indicate that the hens were negatively affected by HS and the response was different for acute and chronic time points. At the acute time point the changes to the hen's physiology were caused by altered blood chemistry, but after chronic exposure, the low feed intake seemed to influence the responses. / Master of Science

O objetivo desse estudo foi avaliar o efeito da inclusão de fibra na dieta de poedeiras comerciais. Para tanto, foram utilizadas 416 poedeiras comerciais, da linhagem Lohmann LSL, distribuídas em um delineamento inteiramente casualizado em quatro tratamentos com 13 repetições de oito aves em cada unidade experimental. Os níveis de fibra estudados consistiram em dietas com a inclusão de 0,0; 0,2; 1,0 e 2,0% de uma fonte comercial de fibra. O período experimental foi conduzido da 24ª a 40ª semana de idade das poedeiras, totalizando quatro ciclos de 28 dias cada. Os dados de desempenho produtivo (produção de ovos, consumo de ração, peso e massa de ovos, conversão alimentar por dúzia e por massa de ovos e percentagem de ovos vendáveis) e a qualidade de ovos (resistência da casca, coloração da gema, altura de albúmen, unidade Haugh e espessura de casca) foram avaliados ao final de cada ciclo de 28 dias. No final do experimento, uma ave por unidade experimental foi separada, para a obtenção dos dados de morfometria intestinal, em que foi retirado o trato intestinal para as avaliações de peso de moela, comprimento de intestino e altura das vilosidades e profundidade de cripta dos segmentos (duodeno, jejuno e íleo). Os dados experimentais do desempenho produtivo obtidos pela média do período experimental foram utilizados para a realização da análise econômica. Observou-se que no desempenho produtivo, os níveis de inclusão de 1,0 e 2,0% de fibra na dieta promoveram efeito significativo positivo sobre o peso e massa de ovos. Na qualidade de ovos os diferentes níveis de fibra apresentaram melhora sobre a resistência e espessura de casca. Na análise de morfometria intestinal observou que as aves alimentadas com diferentes níveis de fibra na dieta obtiveram maior comprimento de intestino, maior altura de vilosidade no jejuno e melhor relação altura da vilosidade:profundidade de cripta no íleo. Em relação à análise econômica o nível de inclusão de 0,2% de fibra na dieta obteve resultados iguais aos da dieta controle sobre custo total, custo total por ave e entre o custo total sobre a renda total. Concluindo-se que a inclusão de 1,0 e 2,0% de fibra na dieta de poedeiras pode causar efeitos positivos sobre os parâmetros de desempenho produtivo, qualidade de ovos e no desenvolvimento da mucosa intestinal. E pelo ponto de vista econômico a inclusão de 0,2% de fibra na dieta é mais viável. / The aim of this study was to evaluate the effect of fiber inclusion on the diet of laying hens. Therefore, 416 commercial laying hens of the Lohmann strain were distributed in a completely randomized design in four treatments with thirteen replicates of eight birds per experimental unit. The fiber levels studied consisted of diets with inclusion of 0,0; 0.2; 1,0 and 2,0% from a commercial source of fiber. The trial was conducted from the 24th to 40th week of birds\' age, totaling 4 cycles of 28 days each. The data of productive performance (egg production, feed intake, egg weight and mass, feed conversion per dozen and egg mass and percentage of salable eggs) and egg quality (eggshell strength, yolk color, albumen height, Haugh unit and eggshell thickness) were evaluated at the end of each 28-day cycle. At the end of the experiment, one bird per experimental unit was separated to obtain the intestinal morphometry data, in which the intestinal tract was removed for gizzard weight, intestine length and villus height and crypt depth of the segments (duodenum, jejunum and ileum). The experimental data of the productive performance obtained by the mean of the experimental period were used for the accomplishment of the economic analysis. It was observed that in the productive performance, inclusion levels of 1,0 and 2,0% of dietary fiber promoted a significant effect on egg weight and egg mass. In the egg quality the different levels of fiber presented improvement on the resistance and thickness of the shell. In the analysis of intestinal morphometry, it was observed that the birds fed different levels of fiber in the diet obtained a longer intestine length, a higher villus height in the jejunum and a better villus height ratio: crypt depth in the ileum. Regarding the economic analysis, the inclusion level of 0.2% fiber in the diet obtained results equal to the control diet over feeding cost, feeding cost per bird and between feeding cost over total revenue. It was concluded that the inclusion of fiber in the laying diet can cause positive effects on parameters of productive performance, egg quality and intestinal mucosa development. And from the economic point of view the inclusion of 0.2% fiber in the diet is more viable.

O presente experimento foi conduzido para avaliar o uso de enzimas fitase e carbohidrolase em dietas a base de milho e soja com ou sem alta concentração de fibras no desempenho produtivo e qualidade dos ovos (gravidade especifica (GE), unidade haugh (UH), espessura da casca (EC) e peso da casca (PC) de galinhas poedeiras. Foram utilizadas 320 poedeiras da linhagem comercial Hissex White, com idade inicial de 44 semanas. As aves foram alimentadas com quatro diferentes tratamentos (10 repetições de 8 cada) durante 10 semanas. As dietas incluíam: controle (T-1) a base de milho e soja com baixa concentração de fibras; (T-2) a base de milho e soja com alta concentração de fibras; (T-3) a base de milho e soja com adição do complexo enzimático e (T-4) a base de milho e soja com adição do complexo enzimático e alta concentração de fibras. As galinhas alimentadas com a dieta controle, apresentaram maior consumo de ração (CR) (P<0,05) na primeira e na quinta semanas em relação ao controle negativo (T-2). Somente na quinta semana o grupo controle obteve maior conversão alimentar (CA) (P<0,05) em relação aos outros tratamentos. Nas outras variáveis observadas, como o peso dos ovos (PO), a massa dos ovos (MO), gravidade específica (GE), unidade Haugh (UH), espessura da casca (EC) e peso da casca (PC), os diferentes tratamentos determinaram resultados similares, isso pode indicar que dietas com alta concentração de fibras e por isso de baixo custo, podem ser adotadas sem diminuição da qualidade e produção dos ovos. / The present experiment was conducted to evaluate the use of enzymes phytase and carbohydrase in corn/soybean meal diets with or without fibers regarding the productive performance and egg quality (specific gravity (SG), Haugh unit (HU), shell thickness (ST) and shell weight (SW) of laying hens. Were utilized 320 commercial line Hissex White laying hens, aged 44 weeks. The hens were fed with four different treatments (10 replicates of eight each) during 10 weeks. The diets included control (T-1) based of corn, soybean meal and low concentration of fibers; (T-2) based of corn, soybean meal and high concentration of fibers; (T-3) based of maize and soybean meal supplemented with enzymes and (T-4) based of corn and soybean meal supplemented with enzymes and high concentration of fibers. The laying hens fed with the control diet (T-1) showed higher feed intake (FI) (P<0,05) in the first and fifth weeks in relation to the negative control (T-2). Only in the fifth week the control group had higher feed conversion (FC) (P<0,05) in relation with the other treatments. In the other variables observed, the different treatments showed similar results, it may indicate that diets with high fiber concentration and therefore low cost can be taken without decreasing the quality and egg production.

Dois experimentos foram conduzidos com os objetivos de avaliar o desempenho e a qualidade dos ovos de poedeiras alimentadas com dietas formuladas com base nos critérios de aminoácidos totais (AAT) e digestíveis (AAD) (Experimento 1) e com diferentes relações arginina:lisina e fontes de metionina na estação de verão (Experimento 2). No Experimento 1, cento e sessenta poedeiras semipesadas com 54 semanas de idade foram distribuídas em delineamento inteiramente ao acaso em arranjo fatorial 2 x 4, sendo os fatores: critério de formulação das dietas (AAT e AAD) e diferentes níveis de aminoácidos (100%, 95%, 90% e 85% de metionina, lisina e triptofano), totalizando oito tratamentos com cinco repetições de quatro aves cada. Foram avaliadas as características de desempenho, de qualidade dos ovos. Os resultados indicaram que não houve efeito significativo dos fatores sobre as características consumo de ração, consumo de energia e peso dos ovos e em nenhuma das características de qualidade dos ovos. A produção de ovos foi influenciada pelos níveis de aminoácidos na dieta, apresentando efeito linear positivo (P<0,05). Verificou-se interação significativa entre os fatores para as características massa de ovos e conversão alimentar, na qual os melhores resultados foram obtidos com o critério AAD e 100% das exigências de aminoácidos. No Experimento 2, foram utilizadas 288 poedeiras com 25 semanas de idade, distribuídas em delineamento inteiramente casualizado em arranjo fatorial 2x3x2: critérios de formulação (AAT e AAD), relações arginina:lisina (0,9:1,0; 1,0:1,0 e 1,1:1,0) e fontes de metionina (pó e líquida), totalizando 12 tratamentos com seis repetições de quatro aves cada. Foram avaliadas as características de desempenho e qualidade dos ovos. Os fatores critérios de formulação e fontes de metionina não influenciaram as características consumo de ração, produção, peso dos ovos, massa de ovos e conversão alimentar. No entanto, o fator relação arginina:lisina influenciou linear e positivamente as características consumo de ração, peso e massa de ovos. As características que expressam a qualidade interna e externa dos ovos não foram influenciadas por nenhum dos fatores estudados. Concluiu-se que o desempenho de poedeiras semipesadas pode ser melhorado quando as dietas são formuladas com base no critério de AAD sem acarretar diminuição na qualidade dos ovos e que a melhor relação arginina:lisina em dietas para poedeiras comerciais leves criadas na estação de verão é de 1,1:1,0. / Two experiments were carried out to evaluate the performance and egg quality of laying hens fed diets formulated based on total (TAA) and digestible (DAA) amino acids (Experiment 1), containing different arginine:lysine ratios and methionine sources at summer season (Experiment 2). In Experiment 1, one hundred sixty brown hens, 54 weeks of age, were randomly distributed in a 2x4 factorial scheme: feed formulation criterion, and amino acid levels (100%, 95%, 90%, and 85% of the methionine, lysine and tryptophan) totaling eight treatments with five replicates of four birds each. Performance and egg quality characteristics were evaluated. The results showed no effects of the factors on feed intake, energy intake, egg weight and on all egg quality characteristics. There was positive linear effect (P<0.05) of the amino acid levels on egg production and significant interaction between the factors on egg mass and feed conversion showing that feeding formulation based on digestible amino acids with 100% of the amino acids provided the best results. In Experiment 2, two hundred eighty eight white hens, 25 weeks of age, were randomly distributed in a 2x3x2 factorial scheme: feed formulation criterion, arginine:lysine levels and methionine sources totalizing 12 treatments with six replicates of four birds each. There were no effects of the feed formulation criterion and methionine sources on feed intake, egg production, egg weight, egg mass, and feed conversion. However, the arginine:lysine ratios influenced linear and positively the feed intake, egg weight, and egg mass characteristics. Egg quality characteristics were not influenced by the factors. It was concluded that the performance of the brown laying hens can be improved by using diets formulated with digestible amino acids criterion, and the arginine:lysine ratio of 1.1:1.0 is the best ratio for white laying hens under summer conditions.

A perda de qualidade de ovos é um processo inevitável e contínuo ao longo do tempo. Existem legislações vigentes no Brasil quanto à temperatura e estocagem de ovos comerciais, no entanto ainda são necessárias pesquisas sobre a vida de prateleira de ovos provenientes do sistema orgânico. O trabalho teve como objetivo avaliar vida de prateleira de ovos, oriundos de poedeiras de produção orgânica, em diferentes idades de postura, considerando a qualidade externa e interna do ovo. Os ovos foram coletados em uma granja com certificação de produção orgânica do município de Viamão- RS. O delineamento experimental foi inteiramente casualizado em fatorial 6x4 - 6 idades de postura x 4 períodos de armazenamento. Foram coletados 288 ovos de aves semi-pesadas em diferentes idades de postura (40, 50, 60, 70, 80 e 90 semanas), e as avaliações de qualidade foram realizadas aos zero (dia da coleta), 14, 28 e 42 dias de armazenamento. Cada período de armazenamento possuía 12 repetições e os ovos foram estocados em sala com controle de umidade (70 ± 4 %) e temperatura (14 ± 2°C). Os ovos foram pesados no dia da coleta e nos dias de avaliação para identificação da perda de peso ao longo do armazenamento As variáveis analisadas foram: peso do ovo, unidade Haugh, altura do albúmen, porcentagem de albúmen, gema e casca do ovo, estabilidade da espuma do albúmen, espessura da casca, pH do albúmen e perda de peso dos ovos. Houve interação da idade da ave e o período de armazenamento (P<0,05) dos tratamentos avaliados sobre a perda de peso do ovo. Poedeiras jovens (40 semanas de idade) apresentam melhor qualidade interna dos ovos com menores perdas de qualidade quando comparadas a aves com 50 e 60 semanas de idade durante o armazenamento por até 42 dias. A estabilidade da espuma do albúmen é melhor em aves mais velhas. O pH do albúmen não é afetado pela idade das poedeiras, mas apresenta aumento significativo em maiores períodos de armazenamento. A vida de prateleira de ovos de produção orgânica pode ser estendida até os 42 dias de armazenamento. Os ovos provenientes de poedeiras mais velhas apresentam qualidade interna superior nos primeiros dias de estocagem, porém com alta susceptibilidade de perdas durante o armazenamento por até 42 dias. / The loss of quality in egg is an inevitable and continuous process over time. There are laws in force in Brazil regarding the temperature and storage of commercial eggs, however, it is still necessary to research on the shelf life of eggs from the organic system. The objective of this work was to evaluate the shelf life of eggs from organic laying hens at different ages, considering the external and internal quality of the egg. The eggs were collected in a farm with certification of organic production of the municipality of Viamão - RS. The experimental design was completely randomized in factorial 6x4 - 6 posture ages x 4 storage periods. A total of 288 eggs were collected at different ages (40, 50, 60, 70, 80 and 90 weeks), and quality evaluations were performed at zero (day of collection), 14, 28 and 42 days of storage. Each storage period had 12 replicates and the eggs were stored in a room with humidity control (70 ± 4%) and temperature (14 ± 2 ° C) The eggs were weighed on the day of collection and on the evaluation days to identify weight loss throughout storage. The variables analyzed were: egg weight, Haugh unit, albumen height, albumen percentage, egg yolk and egg shell, albumen foam stability, shell thickness, albumen pH and egg weight loss. There was interaction between the age of the fowl and the storage period (P <0.05) of the evaluated treatments on egg weight loss. Young laying hens (40 weeks of age) show better internal quality of eggs with lower quality losses when compared to birds at 50 and 60 weeks of age during storage for up to 42 days. The stability of albumen foam is best in older birds. The pH of the albumen is not affected by the age of laying hens, but presents a significant increase in longer periods of storage. The shelf life of organic production eggs can be extended up to 42 days of storage. Eggs from older laying hens have superior internal quality in the first days of storage, but with high susceptibility of losses during storage for up to 42 days.

This dissertation is an investigation into the effect of different zinc sources and levels on eggshell quality and microstructure, as well as keel bone damage. Eggshell function is two-fold; eggshells function to protect the developing embryo, as well as act as a barrier against bacterial penetration, optimizing food safety of the egg for human consumption (Mabe et. Al., 2003). Two small trials were conducted in order to determine differences in eggshell microstructure of eggs produced from hens at peak lay (26 weeks of age) and at the end of lay (88 weeks of age). Two groups of hens were fed a calcium sufficient or a calcium deficient diet. From this it was determined that eggs with higher breaking strengths had some differences in eggshell microstructure. Eggs with greater breaking strengths had a greater density of ‘normal’ structures, compared to ‘abnormal’ structures. Additionally, eggs requiring a greater breaking force, had a thicker micro-structure, compared to shells requiring less breaking force. With this knowledge on microstructure, a larger, 36-week study was conducted using different zinc sources. Every four weeks, eggs were collected and standard egg quality measurements were taken and keel bones were scored. At the end of the study, keel bones were collected from randomly selected hens representing each treatment. Picture of these keel bones were taken and measurements were taken to determine type and degree of deformation, in comparison to scores taken on the live bird. Pens selected for keel bone analysis, were the same pens that eggs were taken for imaging by the scanning electron microscope, to determine eggshell microstructure. From this data, it was determined that egg quality differences were detected, as well as differences in eggshell microstructure. Additionally, keel bone scores progressively worsened throughout the 36-week long study, with type and degree of deformation differing depending on zinc source.

Two trials compared the effects of canola meal (CM) and juncea meal (JM) with and without dietary enzyme supplementation, on production performance, egg quality, bone quality and liver health characteristics of white- (WSLH) and brown-shell egg laying hens (BSLH). A total of 360 Lohmann LSL-Lite White (Trial 1, WSLH) and 300 Lohmann Brown-Lite (Trial 2, BSLH) laying hens were fed one of 10 isoenergetic and isonitrogenous diets (Soybean meal, 10 % CM, 20 % CM, 10 % JM or 20 % JM with or without a dietary enzyme cocktail of Superzyme OM and Bio-PhytaseTM) for 48 weeks. Based on the results of production performance, incidence of mortality, egg quality, bone quality, and liver health data, up to 20 % CM or JM can be included in diets of WSLH and BSLH without detrimental effects. Enzyme should be included in diets for both WSLH and BSLH.

The objective of this thesis was to evaluate inclusion of up to 35% by-product DDGS (with reduced Ca and P) with and without addition of a proprietary premix (enzyme and antioxidant; Alltech Inc.) on productive performance and egg quality of white and brown egg laying hens. A total of 288 white or brown hens were randomly allocated to one of the following treatments: 1) corn-soybean meal (control), 2) 25% DDGS, 3) 25% DDGS plus premix, 4) 35% DDGS, and 5) 35% DDGS plus premix. Hen body weight values were impaired with addition of 25 and 35% DDGS when compared to the control. Premix helped maintain body weight comparable to control in the brown hens; however was not noted in white hens. In the second dietary phase, addition of DDGS increased feed intake in white egg laying hens and was maintained with the premix. Brown hens on premix came into lay faster than the control and DDGS diets, but DDGS reduced overall egg production. Haugh units, yolk color, and purchase intent scores were increased in brown eggs with DDGS diets. White eggs had increased yolk color with DDGS. In conclusion, up to 35% DDGS is acceptable in white laying hen diets.

Darbo tikslas: Išanalizuoti lesalų, praturtintų saulėgrąžų, rapsų ir sėmenų aliejais, įtaką vištų dedeklių produktyvumui ir kiaušinių kokybei. Darbo uždaviniai: 1. Įvertinti saulėgrąžų, rapsų ir sėmenų aliejų riebalų rūgščių sudėtį; 2. Išanalizuoti lesalų, praturtintų saulėgrąžų, rapsų ir sėmenų aliejais, įtaką vištų dedeklių produktyvumui; 3. Išanalizuoti lesalų, praturtintų saulėgrąžų, rapsų ir sėmenų aliejais, įtaką vištų dedeklių kiaušinių kokybei. Tyrimo metodika. Lesinimo bandymas atliktas su 30 savaičių amžiaus Lohmann Brown linijų derinio 30 vnt. dėsliosiomis vištomis, suskirstytomis į 3 grupes (kiekvienoje po 10 vištų). I grupės dėsliosios vištos buvo lesinamos lesalais su 4,5 proc. saulėgrąžų aliejaus priedu, II grupės su 4,5 proc. rapsų aliejaus, o III grupės su 4,5 proc. Visų grupių lesalų energetinė vertė buvo vienoda. sėmenų aliejaus priedu. Bandymo metu dėsliosios vištos laikytos individualiuose narveliuose su stacionariomis lesalinėmis bei girdytuvėmis, vienodomis lesinimo ir laikymo sąlygomis. Paukščiai lesinti granuliuotais kombinuotaisiais lesalais po 125 g per parą. Kiekvieną dieną skaičiuoti ir sverti visi kiaušiniai, paskaičiuotas vištų dėjimo intensyvumas. Kas 14 dienų nustatytas individualus vištų kūno svoris, sverti lesalų likučiai ir apskaičiuotos lesalų sąnaudos 1 kg kiaušinių masės pagaminti. Bandymo pabaigoje buvo tiriami šie parametrai: nustatomi riebalų rūgščių, cholesterolio, malondialdehido kiekiai kiaušinių tryniuose. Taip pat nustatytos... [toliau žr. visą tekstą] / Aim of master thesis: To analyze the feed, enriched with sunflower, canola and flaxseed oils influence on productivity of laying hens and egg quality. Objectives are: 1. To evaluate a nutritional value of sunflower, rapeseed and flaxseed oils; 2. To analyze influence of compound feed, enriched with sunflower, rapeseed and flaxseed oils, on productivity of laying hens; 3. To analyze influence of compound feed, enriched with sunflower, rapeseed and flaxseed oils, on laying hens egg quality. Methods: A test of feeding was performed on thirty 30 weeks old Lohman Brown cross laying hens which were divided into 3 groups (each of 10 hens). Laying hens of a group I were fed feeds containing 4,5 % sunflower oil, group II – 4,5 % rapeseed oil, group III – 4,5 % flaxseed oil. All diets were isocaloric. During the test laying hens were held in individual cages with stationary trough feeders and waterers on equal feeding and keeping conditions. Laying hens were fed with compounds feeds of 125 g per day. All the eggs were counted and weighted daily including the calculations of egg laying intensity. The following actions were performed every 14 days: identification of individual hen body weight, weighting of feed residue and calculation of feed required for production of 1 kg egg mass. At the end of the test these parameters were investigated: determination of fatty acids, cholesterol and malondialdehyde quantities in the yolk of eggs. Also, egg sensory and texture properties of fresh... [to full text]

Tyrimo problema: siekiant apsaugoti riebalus nuo oksidacijos dažniausiai yra naudojami sintetiniai antioksidantai. Kaip rodo moksliniai tyrimai dažniausiai naudojamas neorganinis selenas. Duomenų apie organinį seleną bei vitaminą E, naudojant vištų lesinime saulėgrąžų aliejų, yra nedaug ir jie yra prieštaringi. Be to, aliejų kokybei išsaugoti neteisingai parenkant antioksidantus, tame tarpe seleną ir vitaminą E, vyksta aliejuose antioksidaciniai procesai, kurių metu susidaro laisvieji radikalai. Pastarieji neigiamai veikia tiek gyvūnų, tiek žmonių sveikatingumą. Todėl magistrinio darbo tikslas yra ištirti organinio seleno ir vitamino E įtaką vištų dedeklių produktyvumui bei kiaušinių kokybei, praturtinant jų lesalus saulėgrąžų aliejumi. Darbo uždaviniai: 1. Nustatyti organinio seleno ir vitamino E įtaką vištų dedeklių dėslumui, lesalų sąnaudoms, išsaugojimui bei vištų fiziologiniai būklei, praturtinant jų lesalus saulėgrąžų aliejumi; 2. Nustatyti organinio seleno ir vitamino E įtaką kiaušinių kokybiniams ir kiekybiniams parametrams, praturtinant jų lesalus saulėgrąžų aliejumi; 3. Nustatyti organinio seleno ir vitamino E įtaką jusliniams kiaušinių rodikliams, praturtinant jų lesalus saulėgrąžų aliejumi. Svarbiausios išvados: • Kontrolinės ir tiriamosios grupės vištų svoriai atitiko linijų derinio Lohmann brown auginimo rekomendacijas. • Vitamino E – 40 mg/kg ir organinio seleno 0,5 mg/kg lesalų padidino vištų dėjimo intensyvumą 3,22 proc., tačiau lesalų sąnaudoms 1 kg... [toliau žr. visą tekstą] / The issue of investigation: To prevent fat from oxidation, synthetic antioxidants are most frequently used. Scientific investigations evidence the prevalence of inorganic selenium. The data on selenium and Vitamin E, using sunflower oil in poultry nutrition, is scarce and controversial. Furthermore, the failure in selecting the antioxidants to preserve oil quality causes oil ant oxidation processes during which free radicals are formed. The latter have negative impact on health of both human beings and animals. Therefore, the aim of the master thesis is to investigate the effect of organic selenium and vitamin E on productivity and eggs quality of layer hens when their nutrition is enriched with sunflower oil. The tasks of the work: 1. To determine the impact of organic selenium and vitamin E on egg laying, usage of feed conversion, livability and physiological condition of layer hens when their nutrition is enriched with sunflower oil. 2. To determine the impact of organic selenium and vitamin E on egg qualitative and quantitative parameters when the hens’ nutrition is enriched with sunflower oil. 3. To determine the impact of organic selenium and vitamin E on egg sensory indices when the hens’ nutrition is enriched with sunflower oil. The most important conclusions: • The hens’ weights in control and trial groups met the rearing recommendations for Lohmann Brown line. • The feed additive of vitamin E – 40mg/kg and 0.5mg/kg of organic selenium increased egg laying intensity... [to full text]