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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Restrição alimentar e utilização de calcário de granulometria grosseira com métodos alternativos de muda forçada /

Molino, Andréa de Britto, 1982- January 2010 (has links)
Orientador: Edivaldo Antonio Garcia / Banca: Otto Mack Junqueira / Banca: José Roberto Sartori / Resumo: Com o objetivo comparar métodos alternativos de muda forçada ao jejum, realizou-se um experimento utilizando-se 420 poedeiras com 80 semanas de idade. O período experimental teve duração de 28 dias onde se realizou a muda forçada. Utilizou-se delineamento experimental em esquema fatorial 5x2, contendo cinco restrições alimentares (0, 15, 30, 45 e 60g de ração/ave/dia) com e sem utilização de calcário de granulometria grosseira, e sete repetições de seis aves por parcela. A muda teve duração de 28 dias, porém, os tratamentos que perderam 25% do peso corporal antes deste período foram alimentados à vontade logo após atingirem a perda almejada. Para avaliação da qualidade dos ovos utilizou-se dois ovos por parcela. Durante os 28 dias da muda avaliou-se a perda de peso corporal, o desempenho das aves e a qualidade dos ovos. Conclui-se que o fornecimento de 15g de ração foi viável para efetuar a muda forçada, pois as aves deste tratamento atingiram perda corporal de 25% e apresentaram qualidade dos ovos semelhante às submetidas ao jejum. A adição de calcário de granulometria grosseira durante a muda melhorou a qualidade da casca dos ovos, com exceção ao tratamento em jejum. / Abstract: With the objective to compare alternative methods of forced molt, there was an experiment using 420 hens with 80 weeks of age. The experimental period lasted 28 days there was a forced molting. A randomized trial in a 5x2 factorial arrangement with five dietary restrictions (0, 15, 30, 45 and 60 g of feed / bird / day) with and without the use of limestone coarse particle size, and seven replicates of six birds per plot. The changes lasted 28 days, however, the treatments that have lost 25% of body weight before this period were fed ad libitum after reaching the desired loss. To assess the quality of the eggs we used two eggs per plot. During the 28 days of the changes evaluated the weight loss, bird performance and egg quality. It follows that the supply of 15 g of feed is feasible to make the changes forced the birds because of this treatment reached body loss of 25% and showed the quality of eggs similar to those submitted to fasting. The addition of limestone for the coarse particle size changes improved the quality of shell eggs, except for the fasting treatment. / Mestre
42

Vida de prateleira de ovos de poedeiras com diferentes idades de postura em sistema orgânico de produção / Shelf life of eggs of laying hens with different ages in organic production system

Poletti, Bruna January 2017 (has links)
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.
43

Uso de complexo enzimático (carbohidrase e fitase) em dietas de galinhas poedeiras / Effect of enzyme complex (carbohydrase and Phytase) in laying hens diets

Amanda Fernandes Beccaccia 31 July 2012 (has links)
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&lt;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&lt;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&lt;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&lt;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.
44

Formulação de dietas com aminoácidos totais e digestíveis, diferentes relações arginina:lisina e fontes de metionina para poedeiras comerciais / Feed formulation with total and digestible amino acids, different arginine:lysine ratios and methionine sources for commercial laying hens

Henrique Rosa Baltazar de Souza 05 June 2009 (has links)
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.
45

Fibra na dieta de poedeiras comerciais / Fiber in the diet of commercial laying hens

Brunna Garcia de Souza Leite 24 August 2018 (has links)
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.
46

Effect of a Partial Replacement of Limestone by a Caso<sub>4</sub>-Zeolite Mixture Combined With a Slight Protein Reduction on Production Indices, Egg Quality, and Excreta pH in Laying Hens

Romero, C., Onyango, E. M., Powers, W., Angel, R., Applegate, T. J. 20 June 2012 (has links)
A control diet (CN diet; 17.4% CP and 4.37% Ca) was compared with an experimental diet with a 0.4-percentage-unit reduction in protein content and a 35% replacement of limestone by a CaSO4-zeolite mixture [5.76% CaSO4 and 1.18% zeolite; reduced-emission diet (RE diet)] in laying hens to evaluate the effects on apparent N retention, egg production, egg composition, and excreta pH measured at excreta collection or after 7 d of storage. In previous studies, it was demonstrated that the RE diet reduced NH3 emissions by 48%. Laying hens (192 total; 48 replicate cages per diet, with 2 hens per cage) were fed experimental diets from 33 to 49 wk of age. Apparent N retention (48.2%), egg production (83.6%), and number of shell-less eggs (0.18%) were not affected by the diet. Eggs tended to be heavier (59.4 vs. 58.8 g/egg, P = 0.06), and yolk percentage (29.7 vs. 29.0%, P = 0.013) was greater with the RE diet. At 48 wk of age, the total solids content per egg was also greater from hens fed the RE diet (13.2 vs. 12.6 g/egg, P = 0.032). Other egg components were not influenced by diet. Thus, a slight reduction in dietary CP content and replacing a portion of the Ca from CaCO3 with CaSO4 did not affect egg production nor did it impair shell quality. At the end of the experiment, excreta were collected from all cages (excreta from 3 cages were mixed and pooled; 16 pools of excreta per diet). At collection, excreta of hens fed the RE diet had lower pH (5.89 vs. 6.54, P < 0.001) than those of hens fed the CN diet. After 7 d of storage, excreta pH of hens fed the RE diet continued to be lower (6.30 vs. 8.36, P < 0.001). The reduction of excreta pH, even after 7 d of storage, may control nitrogenous emissions from excreta by maintaining excreted N as NH4+.
47

A Comparative Study of the Effects of Microalgae on Poultry Production

O'Lear Reid, Taylor Kaitlyn 01 June 2022 (has links) (PDF)
Research has shown Spirulina to be a viable feedstuff in poultry production. Other species of microalgae are being studied to determine their effects on poultry production. This project compared four microalgaes: Hydrodictyon, Vaucheria, Uronema, and Spirulina and was broken down into three trials. The first experiment investigated the digestibility of an algae species, Spirulina, in broiler chicken diets. Eighty, 25-day-old Ross 708 broiler chicks were sorted into 20 metabolism cages and received one of two diets: Control Diet or Test Diet (75% basal diet + 25% Spirulina). The apparent ileal amino acid digestibility (AIAAD) of lysine, methionine, cysteine, threonine, isoleucine, valine and arginine in Spirulina was 94.5%, 91.3%, 56.1%, 71.4%, 76.8%, 69.8% and 90.4% respectively. Apparent metabolizable energy (AME) of Spirulina was 2279 kcal/kg. The second experiment focused on digestibility of Spirulina and novel algae species in laying hens. Sixty, 80-week-old Lohman LSL-Lite laying hens were randomly assigned to Control Diet, Hydrodictyon Test Diet (87.5% basal diet + 12.5% hydrodictyon), 12.5% or one of three other test diets (75% basal diet + 25% Spirulina, Uronema, and Vaucheria). Spirulina diets contained the highest crude protein (25.5%) and methionine levels (0.68%). Uronema had the highest gross energy content of 3880.5 kcal/kg and lysine levels (1.12%). Hydrodictyon diet was the most nutritionally similar to the control. Crude protein was at 15.3% and 16.6% for control and Hydrodictyon respectively. Gross energy was 3429.6 kcal/g in control versus 3316.1 kcal/kg in Hydrodictyon. Lastly, crude fat was 2.7% compared to Hydrodictyon at 2.4%. The last trial was to determine the effects of the addition of microalgae in the diet on laying hen production. Seventy-eight, 23-month-old laying hens were assigned to 1 of 3 of the following experimental diets: control, control + 1% microalgae, or control + 2% microalgae. Microalgae, regardless of inclusion level, had no significant effect on egg weight in this study. Increasing level of inclusion of Spirulina, Hydrodictyon, and Uronema from 0 to 2 % significantly increased yolk color. Vaucheria influenced yolk color at the 2% level. No significance differences shown from any of the algae species regardless of inclusion level for egg weight, egg mass, shell thickness, shell strength, shell weight, albumen weight, yolk weight, and albumen height. In addition, there was no significant difference in feed conversion ratio, feed intake, body weight, or tibial strength between the treatments. However, as these are novel algaes, further studies are required to determine the true usability in poultry production.
48

PHENOTYPIC AND GENETIC ANALYSIS OF PERFORMANCE AND WELFARE TRAITS IN PEKIN DUCKS

Carl Kroger (17594145) 12 December 2023 (has links)
<p dir="ltr">The White Pekin duck (<i>Anas platyrhynchos domesticus</i>) is the most widely consumed duck protein in the world. Total duck meat production had a global annual increase of 2.1% per year from 2010 to 2019. The increase in duck meat production can be credited to improved management strategies, nutritional programs, and genetic improvement made to the Pekin ducks by structured breeding programs. Regardless of the advancements already achieved by Pekin duck breeding programs, improvements can still be made. One such improvement that can be made in Pekin duck populations is reducing the frequency of the emerging welfare concern known as flip-over (FO). We hypothesize that egg quality traits, wingspan, back length, and hip width are genetically influenced and their inclusion into Pekin duck breeding programs can be used to improve the Pekin duck. Egg quality traits were collected at weeks of age 30, 32, 35 and 40 on two generations of Pekin duck hens. All heritability estimates and Genetic correlations were calculated using BLUPF90 software, the Restricted Maximum Likelihood (REML) method, and 9,418 individuals in the pedigree. All egg quality traits evaluated are moderate to highly heritable ranging from 0.23 for egg shape to 0.70 for shell ratio. Two hatches of 1,200 Pekin duck hens were assessed at day of age 23 and 30 for wingspan, hip width, and back length using image analysis. Wingspan, hip width, and back length were found to be heritable ranging from 0.04 ± 0.013 to 0.27 ± 0.025 for hip width and back length respectfully. This thesis will discuss approaches to evaluating genetic parameters of egg quality traits in hatching eggs and the possibility of reducing FO through the selection of increased wingspan length.</p>
49

Effect of housing environment and laying hen strain on performance, egg quality and bone properties as well as cloacal and eggshell microbiology

Sharma, Milan Kumar 01 May 2020 (has links)
Laying hen welfare is gaining importance in the United States and several states have passed legislation for a welfareriendly housing environment, which has forced the egg industry to explore alternative housing environments. For this reason, our first objective was to determine the effect of housing environment and laying hen strain on production performance and egg quality. Results showed that production performance of the hens raised in the alternative housing system was similar to the conventional system. The second objective was to compare the eggshell and cloacal microbiology. Our results indicated that the microbial load observed was higher in the alternative system compared to the conventional system. The third objective was to determine the effects of housing environment and laying hen strain on tibia and femur bone properties. The results demonstrated that the alternative system provided better tibia and femur bone characteristics, but it varied among laying hen strains.
50

Roles of limestone particle size ratios and phytase levels on performance, eggshell quality, and bone health in post-peak and late-lay single-cycled W-36 laying hens

Waters, Charis 12 May 2023 (has links) (PDF)
The objective of this study was to investigate the role of fine (F) and coarse (C) limestone ratios and exogenous phytase at standard and superdosing activity on performance, egg quality, and bone quality of post-peak and late-lay Hy-Line W-36 hens. For post-peak, treatments with 40F:60C at 0 and 400 FTU/kg (standard phytase activity) increased hen-day egg production (HDEP). Treatments with 15F:85C decreased feed intake (FI) but also increased unsaleable eggs (UE) and eggshell-breaking strength (EBS). Treatments with 0 and 400 FTU/kg increased albumen quality and treatments with 1500 FTU/kg increased bone quality and phytate breakdown. For late-lay, interaction effects of limestone and phytase were observed for FI, HDEP, UE, bone, and egg quality. Treatments with 40F:60C decreased UE and increased EBS and bone mineral content of aluminum (Al). Treatments with 0 FTU/kg increased eggshell proximate of phosphorus (P) and gizzard pH, but 400 and 1500 FTU/kg increased phytate breakdown and bone quality.

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