Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

Feed withdrawal is commonly used by commercial egg producers to induce molt and stimulate multiple egg-laying cycles in their flocks. However, the practice can compromise the welfare of the birds by elevating stress, suppressing the immune response and causing abnormal behavior. An alternate molt diet was examined using alfalfa diets, and a series of experiments were conducted to evaluate the physiological, immunological and behavioral responses of laying hens fed these diets. We assessed the changes in the levels of blood plasma metabolites after hens were challenged with 106 colony forming units of Salmonella Enteritidis (SE). Hens fed alfalfa diets displayed similar (P ≥ 0.05) levels of cholesterol, glucose, and total protein when compared to full-fed hens. Reduced levels (P ≤ 0.05) of triglycerides were observed in the alfalfa fed and feed withdrawal hens when compared to the full-fed hens. The immune responses of SE challenged laying hens fed alfalfa diets showed similar (P ≥ 0.05) heterophil to lymphocyte ratios (H: L) to full-fed hens whereas the feed withdrawal hens displayed elevated (P ≤ 0.05) H: L ratios. The feed withdrawal hens displayed reduced (P ≤ 0.05) levels of serum IgY early in the trial when compared to the alfalfa and full-fed hens. The alfalfa fed hens displayed lower levels of acid α glycol protein than the feed withdrawal hens and higher levels than the full-fed early during the trial but returned to levels that were similar (P ≥ 0.05) to the full-fed hens. The hens fed alfalfa diets displayed elevated non-nutritive pecking behavior early in the trial however, this behavior declined to levels similar (P ≥ 0.05) to the full-fed hens by the end of the trial. No differences in aggressive behavior were observed between the alfalfa fed hens and the full-fed hens. Hafnium chloride did not effectively mark the alfalfa diet; however, it can be used to track the passage of corn-soy layer ration. This research suggests that the application of alfalfa as an alternative molt diet can be effective in reducing potentially harmful effects which are usually associated with feed withdrawal.

There is increasing interest in developing methods to detect and identify Salmonella, to eliminate or reduce the risk of contamination of shell eggs, and to retain the economic advantages of induced molting without increasing the risk of Salmonella enteritidis infection. S. enteritidis and S. typhimurium are the most common serotypes among 2449 known serotypes of the Salmonella, and are the causes of most egg- related foodborne salmonellosis in humans in the U. S. These two species are also responsible for environmental contamination and the incidence of infections. Therefore, this study was conducted in three phases consisting of ten in vivo and in vitro experiments. This study investigated the effects of zinc on Salmonella growth and survivability in poultry environments, and its ability to induce a molt in single comb white leghorn hens. In part, the antibacterial properties of zinc may reduce environmental contamination in a poultry house by interrupting airborne routes. The first phase involved detecting airborne bacteria by aerosol sampling methods, and then screening any Salmonella mutant (s) that survived desiccation by transposon footprinting. The second phase examined, in vitro, the addition of zinc on the growth kinetics of Salmonella under aerobic or anaerobic conditions, the effects of combinating zinc and acidic conditions on the growth kinetics of Salmonella in vitro under aerobic or anaerobic conditions, and the effects of zinc amended feed on the survival of a dry inoculum of Salmonella. The third phase investigated the ability of zinc propionate, as an alternative salt form of zinc, to induce molt in laying hens, the influence of zinc acetate and zinc propionate on gastrointestinal tract fermentation, and susceptibility of laying hens to S. enteritidis during an induced molt, and the comparison of digestive microbial crop and cecal communities among molted hens fed by either zinc acetate or zinc propionate amended molting diets with hens undergoing feed withdrawal or full fed nonmolted hens using molecular-based denaturing gradient gel electrophoresis.

Salmonellosis affects an estimated 1.4 million people a year with a great majority of cases never being reported. Salmonella Enteritidis (SE) can be found in a variety of foods including poultry meat and eggs. Susceptibility of SE colonization is increased by molting. Induced molting is used in the poultry industry to rejuvenate the hen??s reproductive tract and increase post molt egg quality and production. The most common molting method is complete feed withdrawal. Recent animal welfare pressures have encouraged the industry to seek alternatives to feed withdrawal with one alternative being feeding a high fiber diet like alfalfa. Alfalfa is high in protein, but low in energy which is desirable for a molt diet. Alfalfa??s fermentation properties have been thought to be an inhibitor in pathogen colonization during molting. Including a prebiotic such as fructooligosaccharide (FOS) in the molt diet is thought to further decrease colonization while benefiting the indigenous microflora. Laying hens were molted using alfalfa combined with different ratios of layer ration in an in vivo experiment. The hens responded comparably to the alfalfa molt dietsas they did to feed withdrawal as far as post-molt production parameters were concerned, thus showing that alfalfa was a viable alternative molt diet. Two in vitro studies were designed to evaluate the fermentation properties of alfalfa and layer ration combined with the prebiotic FOS and their abilities to inhibit Salmonella growth. Each treatment was combined with diluted cecal contents and allowed to ferment. The results showed that the most fermentation occurred when alfalfa was the substrate and was slightly increased with the addition of FOS. In addition, combining FOS with alfalfa inhibited Salmonella growth. To integrate these results, an in vivo study was preformed using an alfalfa/layer ration diet from the previous in vivo study with FOS. Volatile fatty acids and lactic acid measurements were made to evaluate fermentation while Salmonella colonization was measured in pertinent organs and in fecal shedding. The results of this study further substantiate alfalfa as a molt diet and conclude that the addition of FOS does, while not statistically significant, further inhibit Salmonella colonization.

O presente estudo teve como objetivo avaliar as principais características de desempenho e qualidade interna e externa dos ovos de poedeiras comerciais brancas submetidas ao fracionamento de cálcio da dieta e diferentes granulometrias de calcário calcítico. Foram utilizadas 270 galinhas ISA-Babcock B-300 N de 40 semanas de idade por quatro períodos de 28 dias cada. O delineamento experimental foi o inteiramente casualizado em arranjo fatorial 3x3, com o fatores: fracionamento de cálcio (2 g Ca manhã e 2 g Ca tarde, 1 g Ca manhã e 3 g Ca tarde, e 3 g Ca manhã e 1 g Ca tarde) e granulometrias de calcário calcítico (mista, grossa e fina) totalizando 9 tratamentos com 5 repetições de 6 aves cada. As características de desempenho zootécnico não foram influenciadas pelos tratamentos com exceção do consumo de ração e de cálcio. O fracionamento de cálcio resultou em maior consumo de ração e cálcio no período da manhã para as aves alimentadas com 3 g de Ca neste período do dia. Para o período da tarde, o maior consumo de ração foi observado em aves alimentadas com 3 g de cálcio em comparação à aves alimentadas com 1 e 2 g de cálcio. Não houve diferença significativa quando avaliou-se o consumo de ração total do dia. O fator granulometria do calcário não influenciou nenhum dos parâmetros estudados com exceção da densidade aparente dos ovos. A utilização de calcário calcítico fino resultou em menor densidade dos ovos em comparação ao calcário calcítico misto ou grosso. Conclui-se que a utilização de calcários com granulometria mista ou grossa beneficia a qualidade da casca dos ovos e que a prática de fracionar o oferecimento de cálcio ao longo do dia não se mostrou vantajosa. No entanto, futuras pesquisas são recomendadas envolvendo o fracionamento de outros nutrientes como fósforo, energia e proteína. / This study was carried out to evaluate the performance and internal and external egg qualities of white commercial laying hens fed diets with different calcium levels and limestone particle sizes. Two hundred seventy ISA-Babcock B-300N hens, 40 weeks of age, were used by four – 28 days period. The experimental design was randomly in a 3x3 factorial arrangement: calcium fractionation (2g Ca morning + 2g Ca afternoon, 1g Ca morning + 3g Ca afternoon, 3g Ca morning + 1g Ca afternoon) and limestone particle size (blended, coarse and fine) with a total of nine treatments with five replicates of six hens each. Performance characteristics were not influenced by the treatments, except feed intake and calcium intake. It was observed higher calcium and feed intake for hens fed 3g Ca in the morning. Also, in the afternoon was verified higher calcium and feed intake for hens fed 3g Ca. There was no effect of the treatments on total daily intake. The limestone particle size improved egg specific gravity when blended or coarse particle size was benefical to eggshell quality. The calcium fractionation did not show be adventageous. However, further researches are indicate to evaluate other nutrients fractionation as phosphorus, energy, and protein.

No description available.

O presente estudo teve como objetivo avaliar as principais características de desempenho e qualidade interna e externa dos ovos de poedeiras comerciais brancas submetidas ao fracionamento de cálcio da dieta e diferentes granulometrias de calcário calcítico. Foram utilizadas 270 galinhas ISA-Babcock B-300 N de 40 semanas de idade por quatro períodos de 28 dias cada. O delineamento experimental foi o inteiramente casualizado em arranjo fatorial 3x3, com o fatores: fracionamento de cálcio (2 g Ca manhã e 2 g Ca tarde, 1 g Ca manhã e 3 g Ca tarde, e 3 g Ca manhã e 1 g Ca tarde) e granulometrias de calcário calcítico (mista, grossa e fina) totalizando 9 tratamentos com 5 repetições de 6 aves cada. As características de desempenho zootécnico não foram influenciadas pelos tratamentos com exceção do consumo de ração e de cálcio. O fracionamento de cálcio resultou em maior consumo de ração e cálcio no período da manhã para as aves alimentadas com 3 g de Ca neste período do dia. Para o período da tarde, o maior consumo de ração foi observado em aves alimentadas com 3 g de cálcio em comparação à aves alimentadas com 1 e 2 g de cálcio. Não houve diferença significativa quando avaliou-se o consumo de ração total do dia. O fator granulometria do calcário não influenciou nenhum dos parâmetros estudados com exceção da densidade aparente dos ovos. A utilização de calcário calcítico fino resultou em menor densidade dos ovos em comparação ao calcário calcítico misto ou grosso. Conclui-se que a utilização de calcários com granulometria mista ou grossa beneficia a qualidade da casca dos ovos e que a prática de fracionar o oferecimento de cálcio ao longo do dia não se mostrou vantajosa. No entanto, futuras pesquisas são recomendadas envolvendo o fracionamento de outros nutrientes como fósforo, energia e proteína. / This study was carried out to evaluate the performance and internal and external egg qualities of white commercial laying hens fed diets with different calcium levels and limestone particle sizes. Two hundred seventy ISA-Babcock B-300N hens, 40 weeks of age, were used by four – 28 days period. The experimental design was randomly in a 3x3 factorial arrangement: calcium fractionation (2g Ca morning + 2g Ca afternoon, 1g Ca morning + 3g Ca afternoon, 3g Ca morning + 1g Ca afternoon) and limestone particle size (blended, coarse and fine) with a total of nine treatments with five replicates of six hens each. Performance characteristics were not influenced by the treatments, except feed intake and calcium intake. It was observed higher calcium and feed intake for hens fed 3g Ca in the morning. Also, in the afternoon was verified higher calcium and feed intake for hens fed 3g Ca. There was no effect of the treatments on total daily intake. The limestone particle size improved egg specific gravity when blended or coarse particle size was benefical to eggshell quality. The calcium fractionation did not show be adventageous. However, further researches are indicate to evaluate other nutrients fractionation as phosphorus, energy, and protein.

Molting is a natural occurrence in the Avian species that can include a period of fasting. Animal rights groups view the longepted standard industry practice as inhumane. Based on influences from these groups and the recommendation of its scientific committee, United Egg Producers (UEP) requires members of its Animal Care Certified Program use a noneed withdrawal molting program, even though the morphological and physiological effects of this method have not been studied in depth and the existing literature provides contradictory results. Research regarding how to induce a noneed withdrawal molt has been performed using feed that is nutrient deficient or contains an additive to cease egg production. Studies have shown subsequent egg production to be comparable to hens molted using feed withdrawal. This study was designed to determine the morphological and physiological changes that occur in a noneed withdrawal molt. Two hundred hens divided into 40 groups of 3 birds each were molted in a staggered pattern so that the morphological and physiological effects of noneed withdrawal molt could be measured with identical environmental and housing variables. Data was divided into 5 sections including Control (n=5), Start (n=7), Mid-Molt (n-7), Near End (n=7), and Over (n=15). Internal organs were examined and measured. Corticosterone levels were measured to determine if noneed withdrawal molting causes less stress to hens. Pertinent blood parameters including cholesterol, glucose, O2, CO2, hemoglobin, and hematocrit were also measured. Results indicate internal organ weight changes due to noneed withdrawal molt were as expected. Decreases in the oviduct length, ovary weight, follicle weight, and follicle number indicate regression of the reproductive tract. No differences (P<0.05) were observed in corticosterone levels, suggesting that a noneed withdrawal molt does not increase stress in laying hens.

Direct-fed microbials (DFM) are a method to increase bird performance and health when antibiotics are removed or limited in the diet. The objective of this experiment was to determine the effects of a single strain Bacillus subtilis DFM on pullet performance, layer performance, and egg quality when fed from day of hatch until 70 weeks of age. In total, 576 Hy-Line W-36 laying hen pullets were randomly divided between two treatments (Control and DFM) on day of hatch across 12 cages for each of the treatments and maintained on those respective treatments for 70-weeks. The DFM was added at a target dose of 300,000 cfu/kg of feed. At the end of the 17-week pullet phase, DFM fed pullets resulted in reduced feed intake, improved FCRm with both similar body weights (P = 0.98) and body composition (P > 0.05) to the control fed pullets. At 17 weeks, 72 birds were randomly selected from each treatment and moved to 12 laying hen cages. At the end of the 52-week laying hen phase, DFM-fed hens had significantly higher hen-day egg production (P = 0.02), but decreased egg weights. No differences were reported in egg mass or feed intake, but FCR was significantly improved (P = 0.02) on a per dozen eggs basis, and improved (P = 0.06) on a g/g basis by 7.1 points with DFM-fed hens having an FCR of 2.016 and control fed hens having and FCR of 2.087. Supplementation of diets with DFM resulted in a trend in egg specific gravity, but no differences were reported in shell breaking strength or shell weight. Overall, supplementation of the DFM lowered feed intake and improved FCR without affecting body composition in the pullet phase, and increased production and improved FCR during the egg laying phase. / Master of Science / Due to the decreased use of antibiotics across the poultry industry, producers and allied companies are developing new methods to increase bird health and performance when antibiotics are removed from or limited in the diet. One such method is through the use of "good" bacteria or technically called Direct-Fed Microbials (DFM). Direct-fed microbials are defined as live microorganisms that when fed, confer a health benefit to the host. The goals of this thesis were to determine the effects of a Bacillus subtilis based DFM on pullet performance, laying hen performance, and egg quality when fed from day of hatch until 70 weeks of age. In the pullet phase, DFM-fed pullets had reduced feed intake and improved feed conversion ratio (the ratio of feed intake to body weight gain), with no differences in body weights or body composition at the end of the 17-week growth period. In the laying phase, DFM fed hens had significantly improved egg production, but lighter eggs compared to the control fed hens. Addition of the DFM significantly improved feed conversion ratio per dozen eggs by 5.3 points and reduced feed conversion ratio on a g/g basis by 7.1 points in the 52-week laying phase. Small improvements were noted in specific gravity, but no differences were reported in shell weight or shell breaking strength. When fed from day of hatch until 70 weeks of age, the Bacillus subtilis DFM allowed the pullets to reduce their feed intake, but maintain body development for egg production resulting in an improved feed conversion ratio (FCR) in the growth phase before egg production and once hens initiated egg production resulted in smaller eggs, but increased egg production and FCR in laying hens with minimal differences in egg quality. Therefore, the DFM may be able to be used in place of growth promoting antibiotics to help support efficient protein production.

Four experiments were conducted to evaluate guar meal as a source of prebiotic galactomannans for laying hens. In the 1st experiment, late phase laying hens were fed diets with 0, 5, 10% guar meal (GM) for 56 days or 15% GM for 28 days then switched to the 0% GM diet for the final 28 days. In the 2nd experiment, young pullets were fed guar germ (GG) or GM at 0, 2.5 or 5% for 20 weeks. In the 1st and 2nd experiments, egg production and feed consumption were not affected by feeding up to 5% guar by-products whereas feed efficiency was decreased by guar feeding. Feeding of GG or GM did not affect egg weight or shell quality, but decreased the egg yolk color and Haugh units. Guar increased absolute and relative liver weight, but did not affect the weights of the pancreas, spleen, or the incidence of fatty liver or liver hemorrhage. Feeding 10% GM depressed feed consumption and increased body weight loss. Feeding 15% GM severely depressed egg production followed by a recovery of production after returning to 0% GM feeding. In the 3rd and 4th experiments, late phase laying hens were induced to molt by feed withdrawal (FW) or feeding 15 or 20% GM with or without β-mannanase (Hemicell??). All hens except those fed 15% GM with enzyme obtained a complete cessation of lay in 10 days. Compared to FW birds, hens fed GM had lower body weight reduction and mortality, while hens fed 20% GM with enzyme had higher post-molt egg production. Salmonella enteritidis (SE) present in 6 organs (crop, liver, spleen, ovary, oviduct and cecum), and SE in cecal contents were significantly reduced by 20% GM feeding with and without enzyme. The results showed that GG or GM can be safely fed to laying hens up to 5% without adverse effects on performance. An alternative molting method employing 20% GM with or without β-mannanase is preferable to FW because GM feeding results in a complete molt and decreases mortality, as well as enhances the resistance to SE of molted hens.