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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.
1

Digestibility of diets containing Enertia s/f® and soybean oil in equines and effect of cobalt chloride on fermentation of alfalfa and smooth bromegrass hay by equine cecal microorganisms

Fehlberg, Laura Kay January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Teresa L. Douthit / Supplementation of lipids in the form of triglycerides is a safe method for increasing energy density in equine diets; however the effects of calcium salts of fatty acids (CSFA) on nutrient digestibilities in the horse are unknown. Eight cecally cannulated Quarter Horses were utilized in a crossover design in which horses consumed 1.5% BW smooth bromegrass hay and 0.5% BW concentrate supplemented with 4.1% soybean oil (SB) or 4.9% Enertia s/f® (E), a proprietary CSFA, for 28 d. Feces were collected for determination of apparent total tract digestibility of nutrients, and cecal digesta was evaluated for pH and concentrations of VFA and LCFA. Serum was collected following a 16-h fast and analyzed for triglycerides and cholesterol. Apparent total tract digestibilities of DM, NDF, ADF, CP, ether extract, and GE were unaffected by lipid source (P > 0.10). Serum triglycerides tended to be greater in horses consuming E compared to SB (P = 0.10); but, serum cholesterol concentrations were not different (P = 0.45). Cecal pH was unaffected by lipid source. Cecal concentration of total VFA tended to be greater in horses consuming SB compared to E at 2-h post feeding (P = 0.07). Cecal propionate concentrations were greater at 2-h post feeding for horses fed SB compared to horses fed E (P = 0.03). A treatment × time interaction was detected for total cecal LCFA concentration in which total cecal LCFA were greater in horses consuming E compared to SB at 2-h following consumption of a meal but became more similar as time progressed (P < 0.01). Secondly, an in vitro study was conducted to determine the effect of Co chloride on fermentation parameters using an equine cecal fluid inoculum in a 2 × 5 factorial arrangement of treatments. Alfalfa or smooth bromegrass hay (5 g DM) were utilized as substrates and were supplemented with 0.0, 0.5, 5.0, 25.0, or 50.0 mg Co/kg substrate DM. Cultures containing alfalfa had greater IVDMD compared to those with smooth bromegrass hay (P < 0.01). There was a forage × Co interaction in which gas production increased with time and was greater in cultures containing alfalfa (P < 0.01). Production of acetate, propionate, butyrate, isobutyrate, isovalerate, and total VFA, as well as acetate:propionate, were increased in cultures containing alfalfa compared to those containing brome hay (P < 0.05).
2

Quality of Applesauce and Raspberry Puree Applesauce as Affected by Type of Ascorbic Acid, Calcium Salts and Chelators under Stress Storage Conditions

Goan, Eric Calvin 01 May 2011 (has links)
Applesauce prepared for the US military is processed as MRE (meals-ready-to-eat) in several forms including Type VI - Applesauce with raspberry puree, and Type VII - Carbohydrate enriched applesauce. Production of MRE applesauce starts with commercially prepared and thermally processed applesauce that is further processed by a military contractor. The further processing includes adjusting pH, ºBrix, and ascorbic acid level, packaging into pouches, and again thermally processing. Both types of the MRE applesauce are very much liked by troops, but under stress storage applesauce darkens and its consumption is drastically reduced. The overall goal of this project was to identify additives to be used during further processing in order to slow darkening when exposed to elevated temperatures during shipping and storage. The specific objective was to determine whether different types of ascorbic acid, calcium salts, or addition of chelators can reduce deterioration under stress storage. Applesauce (AS), applesauce with raspberry puree (RPAS), MRE AS (Type VII) and MRE RPAS (Type VI) for all experiments were provided by Sopakco, Bennettsville S.C. The research was carried out in three phases. From the Phase 1, we learned that Type VII and Type VI darkened at faster rates at the beginning of the storage, but the effects of storage at 50°C for more than 2 weeks overcame any differences caused by further processing. Phase 2 helped us determine the formulations for the processing on the industrial scale. The formulations were: 0.15% L-ascorbic-acid (AA), and 0.15% AA with 300 ppm EDTA for both AS and RPAS, with 0.83% calcium lactate gluconate (CLG) for AS, and 0.15% ascorbyl-palmitate for RPAS. The results from the Phase 3 indicated that AS with addition of CLG and RPAS with total of 0.18% AA had the least total color change. In all samples, accumulation of HMF was related to amount of ascorbic acid with exception of samples with Pal which had the lowest HMF content. Our results indicate that current MRE Types VI and VII may have better stability at stress storage if the level of AA is limited to 0.18% and 0.83% CLG is added to the AS formulation.
3

Fontes de gordura alteram o desempenho e o metabolismo de vacas mantidas em pastagens tropicais / Sources of fat alters performance and metabolism of dairy cows grazing a tropical pasture

Souza, Jonas de 07 February 2014 (has links)
Objetivou-se avaliar a inclusão de fontes de gordura na forma de sais de cálcio na dieta sobre o desempenho e metabolismo de vacas em início e meio da lactação mantidas em pastagens tropicais. No Capítulo 3, foi realizada uma meta-análise para avaliar os efeitos da suplementação de gordura para vacas mantidas em pastagens sobre a produção e a composição do leite. A produção de leite aumentou com a suplementação de gordura, e a suplementação com fontes insaturadas deprimiu o teor de gordura do leite. No capítulo 4, objetivou-se comparar o uso do dióxido de titânio (TiO2) como marcador externo em substituição ao óxido crômico (Cr2O3) para estimar a excreção fecal e calcular o consumo de forragem e a digestibilidade. A excreção fecal tendeu ser maior para os valores estimados pelo Cr2O3. O Cr2O3 superestimou a excreção fecal comparado com a coleta total de fezes. O consumo de forragem e o consumo de MS total foram superestimados pelo Cr2O3, enquanto não foram observadas diferenças entre os valores observados de consumo e estimados pelo TiO2. A digestibilidade aparente da MS foi subestimada tanto pelo Cr2O3 quanto pelo TiO2. No capítulo 5 objetivou-se avaliar os efeitos da suplementação de vacas em início da lactação mantidas em pastagem tropical com diferentes fontes de gordura sobre o desempenho, composição do leite e variáveis produtivas ao longo da lactação. A suplementação de sais de cálcio de óleo de soja (SCOS) aumentou a produção de leite quando comparado com o grupo controle, porém foi inferior a produção dos animais suplementados com sais de cálcio de óleo de palma (SCOP). Apesar do aumento em produção de leite com SCOS, nesse tratamento o teor de gordura do leite reduziu significativamente quando comparado com o grupo controle e ao SCOP. Durante o período residual a produção do grupo que recebeu SCOP continuou maior e refletiu na produção ao longo de toda a lactação (7328 kg lactação-1) comparado ao SCOS (6575 kg lactação-1) e ao controle (6094 kg lactação-1). No capítulo 6, objetivou-se avaliar a suplementação de duas fontes e duas doses de sais de cálcio de ácidos graxos sobre o desempenho, composição do leite, parâmetros ruminais e metabólicos e balanço energético de vacas no meio da lactação mantidas em pastagem tropical. A produção de leite foi afetada pela adição de gordura, sendo influenciada pela fonte e pela dose de gordura. O teor de gordura do leite foi influenciado pela fonte de gordura suplementada. O pH ruminal não foi afetado pelos tratamentos experimentais. A suplementação com SCOS prejudicou a degradação da fibra, reduziu a produção de AGV\'s, reduziu a síntese microbiana e a produção de gordura do leite quando comparado com a fonte de SCOP. Portanto, as estimativas de consumo e digestibilidade foram melhores preditas com o uso do dióxido de titânio como marcador. Além disso, a suplementação com sais de cálcio de óleo de palma aumentou a produção de leite na lactação, não reduziu o consumo e nem a degradação da fibra. / The objective of this study was to evaluate inclusion of different sources of fat as calcium salts in the diet on performance and metabolism of early lactation cows grazing tropical pastures. In Chapter 3, a meta-analysis was performed to evaluate the effects of fat supplementation to grazing dairy cows on milk yield and milk composition. Milk yield increased with fat supplementation, and supplementation with unsaturated sources depressed milk fat content. In Chapter 4, the objective was to compare the use of titanium dioxide (TiO2) as an external marker to replace chromium oxide (Cr2O3) to estimate fecal excretion and calculate forage intake and digestibility. Fecal excretion tended to be greater for values estimated by Cr2O3. The Cr2O3 overestimated and TiO2 tended to overestimate fecal excretion compared to total fecal collection. Forage intake and total DM intake were overestimated by Cr2O3, while no differences were observed between the observed values of consumption and estimated by TiO2. The apparent DM digestibility was underestimated by both Cr2O3 and TiO2. In the chapter 5, it was evaluated the effects of fed different sources of fat to early lactation cows (from 15 to 105 DIM) grazing a tropical pasture on production variables throughout lactation (until 280 DIM). Calcium salts of soybean oil (CSSO) increased milk yield compared to control, but was lower than the production of animals supplemented with calcium salts of palm oil (CSPO). Despite the increase in milk yield with CSSO, this treatment decreased milk fat content and yield when compared with control and CSPO. During the residual period (from 106 to 280 DIM) the group that received CSPO had greater milk yield and reflected in the greater milk yield throughout lactation (7328 kg lactation-1) compared to CSSO (6575 kg lactation-1) and the control (6094 kg lactation-1). In chapter 6, the objective was to evaluate the supplementation with two sources (CSSO vs. CSPO) and two doses (400g vs 700g/day) of calcium salts of fatty to mid lactating dairy cows grazing a tropical pasture on performance, milk composition, ruminal and metabolic parameters and energy balance. Milk yield was increased by the addition of fat, being influenced by source and by dose. The milk fat was influenced by source of fat supplementation. The ruminal pH was not affected by experimental treatments. Supplementation with CSSO damaged the fiber degradation, reduced production of VFA \'s, reduced microbial synthesis and the production of milk fat compared with the source of CSPO. In conclusion, DM intake and digestibility were better predicted with the use of titanium dioxide as a marker. Furthermore, supplementation with calcium salts of palm oil increased milk production in lactating without decreasing DM intake and degradation of the fiber.
4

Fontes de gordura alteram o desempenho e o metabolismo de vacas mantidas em pastagens tropicais / Sources of fat alters performance and metabolism of dairy cows grazing a tropical pasture

Jonas de Souza 07 February 2014 (has links)
Objetivou-se avaliar a inclusão de fontes de gordura na forma de sais de cálcio na dieta sobre o desempenho e metabolismo de vacas em início e meio da lactação mantidas em pastagens tropicais. No Capítulo 3, foi realizada uma meta-análise para avaliar os efeitos da suplementação de gordura para vacas mantidas em pastagens sobre a produção e a composição do leite. A produção de leite aumentou com a suplementação de gordura, e a suplementação com fontes insaturadas deprimiu o teor de gordura do leite. No capítulo 4, objetivou-se comparar o uso do dióxido de titânio (TiO2) como marcador externo em substituição ao óxido crômico (Cr2O3) para estimar a excreção fecal e calcular o consumo de forragem e a digestibilidade. A excreção fecal tendeu ser maior para os valores estimados pelo Cr2O3. O Cr2O3 superestimou a excreção fecal comparado com a coleta total de fezes. O consumo de forragem e o consumo de MS total foram superestimados pelo Cr2O3, enquanto não foram observadas diferenças entre os valores observados de consumo e estimados pelo TiO2. A digestibilidade aparente da MS foi subestimada tanto pelo Cr2O3 quanto pelo TiO2. No capítulo 5 objetivou-se avaliar os efeitos da suplementação de vacas em início da lactação mantidas em pastagem tropical com diferentes fontes de gordura sobre o desempenho, composição do leite e variáveis produtivas ao longo da lactação. A suplementação de sais de cálcio de óleo de soja (SCOS) aumentou a produção de leite quando comparado com o grupo controle, porém foi inferior a produção dos animais suplementados com sais de cálcio de óleo de palma (SCOP). Apesar do aumento em produção de leite com SCOS, nesse tratamento o teor de gordura do leite reduziu significativamente quando comparado com o grupo controle e ao SCOP. Durante o período residual a produção do grupo que recebeu SCOP continuou maior e refletiu na produção ao longo de toda a lactação (7328 kg lactação-1) comparado ao SCOS (6575 kg lactação-1) e ao controle (6094 kg lactação-1). No capítulo 6, objetivou-se avaliar a suplementação de duas fontes e duas doses de sais de cálcio de ácidos graxos sobre o desempenho, composição do leite, parâmetros ruminais e metabólicos e balanço energético de vacas no meio da lactação mantidas em pastagem tropical. A produção de leite foi afetada pela adição de gordura, sendo influenciada pela fonte e pela dose de gordura. O teor de gordura do leite foi influenciado pela fonte de gordura suplementada. O pH ruminal não foi afetado pelos tratamentos experimentais. A suplementação com SCOS prejudicou a degradação da fibra, reduziu a produção de AGV\'s, reduziu a síntese microbiana e a produção de gordura do leite quando comparado com a fonte de SCOP. Portanto, as estimativas de consumo e digestibilidade foram melhores preditas com o uso do dióxido de titânio como marcador. Além disso, a suplementação com sais de cálcio de óleo de palma aumentou a produção de leite na lactação, não reduziu o consumo e nem a degradação da fibra. / The objective of this study was to evaluate inclusion of different sources of fat as calcium salts in the diet on performance and metabolism of early lactation cows grazing tropical pastures. In Chapter 3, a meta-analysis was performed to evaluate the effects of fat supplementation to grazing dairy cows on milk yield and milk composition. Milk yield increased with fat supplementation, and supplementation with unsaturated sources depressed milk fat content. In Chapter 4, the objective was to compare the use of titanium dioxide (TiO2) as an external marker to replace chromium oxide (Cr2O3) to estimate fecal excretion and calculate forage intake and digestibility. Fecal excretion tended to be greater for values estimated by Cr2O3. The Cr2O3 overestimated and TiO2 tended to overestimate fecal excretion compared to total fecal collection. Forage intake and total DM intake were overestimated by Cr2O3, while no differences were observed between the observed values of consumption and estimated by TiO2. The apparent DM digestibility was underestimated by both Cr2O3 and TiO2. In the chapter 5, it was evaluated the effects of fed different sources of fat to early lactation cows (from 15 to 105 DIM) grazing a tropical pasture on production variables throughout lactation (until 280 DIM). Calcium salts of soybean oil (CSSO) increased milk yield compared to control, but was lower than the production of animals supplemented with calcium salts of palm oil (CSPO). Despite the increase in milk yield with CSSO, this treatment decreased milk fat content and yield when compared with control and CSPO. During the residual period (from 106 to 280 DIM) the group that received CSPO had greater milk yield and reflected in the greater milk yield throughout lactation (7328 kg lactation-1) compared to CSSO (6575 kg lactation-1) and the control (6094 kg lactation-1). In chapter 6, the objective was to evaluate the supplementation with two sources (CSSO vs. CSPO) and two doses (400g vs 700g/day) of calcium salts of fatty to mid lactating dairy cows grazing a tropical pasture on performance, milk composition, ruminal and metabolic parameters and energy balance. Milk yield was increased by the addition of fat, being influenced by source and by dose. The milk fat was influenced by source of fat supplementation. The ruminal pH was not affected by experimental treatments. Supplementation with CSSO damaged the fiber degradation, reduced production of VFA \'s, reduced microbial synthesis and the production of milk fat compared with the source of CSPO. In conclusion, DM intake and digestibility were better predicted with the use of titanium dioxide as a marker. Furthermore, supplementation with calcium salts of palm oil increased milk production in lactating without decreasing DM intake and degradation of the fiber.
5

Processamento do milho flint associado à suplementação de gordura sobre o desempenho e metabolismo de vacas em pastagem tropical / Corn grain processing associated with fat supplementation on performance and metabolism of dairy cows grazing a tropical pasture

Batistel, Fernanda 25 June 2014 (has links)
O objetivo desse trabalho foi avaliar os efeitos associativos entre o processamento do milho flint e a suplementação de sais de cálcio de óleo de palma (SCOP) para vacas no início de lactação mantidas em pastagem sobre desempenho, metabolismo, variáveis ruminais e a cinética de fermentação. No Capitulo 2, o objetivo desse estudo foi determinar a cinética de degradação do capim elefante, e de concentrados com diferentes fontes de gordura e métodos de processamento de grãos. O concentrado contendo sais de cálcio de óleo de soja- SCOS reduziu o volume de carboidratos fibrosos em comparação ao concentrado controle e ao concentrado contendo sais de cálcio de óleo de palma-SCOP. O fornecimento de milho floculado permitiu aumentar o volume final de CNF, a taxa de degradação dos CNF, a taxa de degradação dos CF e reduzir o lagtime em comparação ao milho moído. No capitulo 3, o objetivo foi avaliar os efeitos associativos entre o processamento do milho flint e a suplementação de SCOP para vacas no início da lactação mantidas em pastagem tropical. Quarenta vacas receberam os seguintes tratamentos: a) milho moído sem adição de SCOP; b) milho moído com adição de 400 g de SCOP; c) milho floculado sem adição de SCOP; e d) milho floculado com adição de 400 g. Posteriormente ao período de fornecimento dos tratamentos (90 dias), o efeito residual desses foi avaliado até o 280° DEL. Não houve interação entre o processamento do milho e o fornecimento de SCOP para nenhuma das variáveis avaliadas. O milho floculado e o fornecimento de SCOP aumentaram em 7,7% e 16% a produção de leite, respectivamente. A utilização de milho floculado aumentou o teor de proteína do leite em 8,3% e o de caseína em 7,3% e reduziu o N ureico do leite em 25,8%. A suplementação de SCOP reduziu os ácidos graxos (AG) de cadeia curta, aumentou os AG saturados e não influenciou os AG poli-insaturados. O consumo de energia liquida foi aumentado em 6% e 4,3% quando do fornecimento de SCOP e milho floculado, respectivamente. A eficiência de uso do N foi maior para os tratamentos com milho floculado e permitiu maior aporte de AA para a glândula mamária. O fornecimento de SCOP e milho floculado permitiram um aumento de 12,7 e 4,6% na produção de leite total na lactação. No capitulo 4, os mesmos tratamentos do capítulo 3 foram aplicados para obter-se os parâmetros ruminais e metabólicos. Foram utilizadas 4 vacas canuladas no rúmen em delineamento de quadrado latino 4×4. As concentrações de acetato, propionato, butírico, isobutírico, isovalérico e a concentração total foram maiores quando do fornecimento de milho floculado em comparação ao milho moído. Além disso, a suplementação com milho floculado reduziu a relação acetato/propionato e a concentração ruminal de N-NH3. Não houve efeito do processamento e da suplementação com SCOP sobre pH médio, pH mínimo e máximo. No entanto, o tempo em que o pH esteve abaixo de 6,0 e abaixo de 6,2 foi maior para o milho floculado em comparação ao milho moído. / The aim of this study was to evaluate the associative effect between flint corn processing and supplementation with calcium salts of palm oil (CSPO) in early lactation grazing cows on performance, metabolism, ruminal variables and fermentation kinetics. In Chapter 2, the aim was to determine the degradation kinetics of elephant grass and concentrates with different fat sources and methods of grain processing. The concentrate containing calcium salts of soybean oil reduced the volume of fibrous carbohydrates compared to the control and the concentrate containing calcium salts of palm oil - CSPO. Steam-flaked corn increased the final volume of NFC, the degradation rate of NFC, the rate of degradation of fibrous carbohydrates and reduced lagtime compared to ground corn. In chapter 3, the associative effect between flint corn processing and CSPO supplementation was evaluated to dairy cows in early lactation grazing on tropical pasture. Forty cows received the following treatments: a) ground corn without CSPO; b) ground corn with CSPO; c) flaked corn with no CSPO; and d) flaked corn with CSPO. After the period treatments period (90 days), the residual effect of these has been reported until 280 DIM. There was no interaction between corn processing CSPO for the variables evaluated. Flaked corn and fat supplementation increased mil yield by 7.7% and 16%, respectively. Flaked corn increased milk protein content in 8.3% and casein in 7.3% and reduced milk urea N by 25.8%. The CSPO reduced short-chain fatty acids (FA) and increased saturated FA and did not influence polyunsaturated FA. The net energy intake was increased by 6% and 4.3% when CSPO and flaked corn were fed, respectively. The efficiency of N utilization was higher for treatments with flaked corn and allowed a greater supply of AA to the mammary gland. Feeding CSPO and flaked corn allowed an increase of 12.7 and 4.6 % in total milk yield during lactation. In chapter 4, the same treatments from chapter 3 were applied to obtain ruminal and metabolic parameters. Four cannulated cows were used in a 4 × 4 Latin square design. Concentrations of acetate, propionate, butyric acid, isobutyric, isovaleric and the total VFA concentration were higher for steam flaked corn compared with ground corn. Furthermore, feeding steam-flaked corn reduced the acetate/propionate ratio and ruminal NH3-N concentration. There was no effect corn processing and supplementation with CSPO on average pH, minimum and maximum pH. However, the time that the pH was below 6.0 and below 6.2 was higher for steam flaked corn compared with ground corn.
6

Metabolismo de nitrogênio, de ácidos nucleicos e ácidos graxos em vacas leiteiras alimentadas com lipídios / Nitrogen, nucleic acids and fatty acids metabolism in dairy cows fed fat diet

Valle, Tiago Antônio Del 24 August 2018 (has links)
Objetivou-se avaliar o efeito da adição de sais de cálcio de ácidos graxos (SCAG) e de diferentes teores de proteína degradável no rúmen (PDR) na dieta de vacas leiteiras sobre: consumo, fermentação e metabolismo de nitrogênio ruminal, desempenho produtivo e balanço de nitrogênio; as estimativas de síntese microbiana utilizando 15N e bases purinas (BP) como indicadores microbianos, a composição dos pellets de bactéria, a recuperação de derivados purina (DP) na urina e a excreção urinária de DP de origem endógena; o fluxo omasal de ácidos graxos, a extensão de bio-hidrogenação e o perfil lipídico das bactérias. Oito vacas em lactação, multíparas e canuladas no rúmen foram usadas em um delineamento em quadrado Latino 4 × 4 replicado, distribuídas em arranjo fatorial 2 × 2 de tratamentos. Os tratamentos foram obtidos pela combinação da adição de SCAG (-SCAG: sem suplementação; e +SCAG: com 3,32% matéria seca (MS) de SCAG) e os teores de PDR (BPDR: baixo PDR, com 9,8% MS de PDR; e APDR: alto PDR: com 11,0% de PDR na MS da dieta). A suplementação lipídica reduziu (P &le; 0,049) o consumo, tendeu (P = 0,076) a aumentar o tempo de ruminação e aumentou (P = 0,015) o pH ruminal. A adição de SCAG diminuiu (P &le; 0,013) a digestibilidade aparente ruminal da MS e matéria orgânica, e tendeu a reduzir (P = 0,096) a digestibilidade ruminal da fibra em detergente neutro (FDN) e reduziu (P = 0,043) o nitrogênio (N) verdadeiramente digerido no rúmen. Apesar de afetar (P = 0,039) negativamente o fluxo de nitrogênio não amoniacal (NNA) associado com as grandes partículas, SCAG não afetou (P &ge; 0,634) o fluxo total de NNA e o fluxo de NNA microbiano, e aumentou (P = 0,032) a eficiência de síntese proteica microbiana. Animais alimentados com SCAG apresentaram maior (P = 0,043) produção de leite, com menor (P &lt; 0,001) teor de gordura, maior (P &lt; 0,001) eficiência alimentar e de uso do N. Animais alimentados com BPDR tenderam (P &le; 0,096) a apresentar maior consumo de proteína bruta e relação entre as concentrações ruminais de acetato e propionato. Ainda, APDR elevou (P &le; 0,048) a digestibilidade aparente total do amido e a digestibilidade ruminal verdadeira do N. O nível de PDR não afetou (P &ge; 0,719) a síntese de proteína microbiana e a eficiência de síntese, enquanto que BPDR aumentou (P &le; 0,055) a produção de leite e reduziu o teor de proteína do leite. O alto nível de PDR tendeu (P &le; 0,088) a reduzir a excreção fecal e o balanço de N, enquanto aumentou (P = 0,021) a excreção urinária relativa ao consumo de N. As bactérias associadas à partícula (BAP) apresentaram menor (P &le; 0,008) enriquecimento com 15N e relação N purinas: N total microbiano do que as bactérias associadas à fase líquida (BAL). A utilização de BP como indicador superestimou (P &le; 0,002) o fluxo microbiano, especialmente de BAL. No entanto, para o fluxo microbiano associado à partícula, houve tendência à interação (P = 0,067) entre os efeitos de indicador e da suplementação lipídica. Na presença de SCAG, BP e 15N apresentaram (P &gt; 0,05) estimativas similares, enquanto que na ausência de SCAG, BP subestimou (P &le; 0,05) o fluxo de BAP, em relação ao 15N. O aumento do nível de PDR da dieta tendeu a reduzir (P = 0,061) o fluxo omasal de BP e reduziu (P = 0,007) a recuperação urinária desta. A recuperação urinária de DP foi extremamente variável (33,9% de coeficiente de variação). As estratégias nutricionais avaliadas não afetaram (P &ge; 0,108) a excreção urinária de creatinina e DP de origem endógena. As excreções diárias de creatinina e DP de origem endógena foram de 0,262 mmol/kg e 640 mmol/kg0,75, respectivamente. O aumento do nível de PDR da dieta resultou na redução (P &lt; 0,001) do consumo dos ácidos graxos C4:0, C12:0, C14:0, C16:0 e C18:0, e tendeu (P = 0,068) a reduzir o consumo de C18:1 trans. Houve interação ou tendência (P &le; 0,095) à interação entre os efeitos do nível de PDR e adição de SCAG sobre o fluxo omasal de ácidos graxos totais e alguns ácidos graxos específicos (C15:0, C16:0, C17:0, C18:0, C18:1 cis-9, C18:2 cis-9 cis-12, C18:3 cis e C22:0). Nas dietas contendo SCAG, nenhum efeito do nível de PDR foi observado sobre o fluxo omasal de ácidos graxos (P &gt; 0,05), enquanto que nas dietas -SCAG, o aumento do nível de PDR aumentou (P &le; 0,05) o fluxo omasal total de ácidos graxos. Consequentemente, o aumento do nível de PDR reduziu (P &le; 0,05) a extensão de bio-hidrogenação do C18:1 cis e C18:3 nas dietas -SCAG, sem efeitos (P &gt; 0,05) nas dietas +SCAG. A adição de SCAG aumentou (P &le; 0,001) a extensão de bio-hidrogenação do C18:2, assim como o teor de AG dos pellets de bactéria. O nível de PDR da dieta não afetou (P &ge; 0,116) o perfil de ácidos graxos dos microrganismos, nem o perfil de ácidos graxos do leite. A adição de SCAG reduziu ou tendeu (P &le; 0,080) a reduzir os teores de C15:0, C16:0, C16:1, C17:0 e C18:0, e aumentou (P &le; 0,005) as concentrações de ácidos graxos insaturados de 18 carbonos nos microrganismos. Além disso, a adição de SCAG reduziu (P &le; 0,009) a concentração de todos os ácidos graxos menores do que 18 carbonos e a razão entre saturados e insaturados na gordura do leite, bem como aumentou (P &le; 0,001) as concentrações dos ácidos graxos com 18 carbonos ou mais e dos ácidos graxos insaturados. Desta forma, a adição de SCAG na dieta reduz o consumo, aumenta o tempo de ruminação, a eficiência microbiana e a produção de leite, sem afetar o fluxo microbiano. O aumento do nível de PDR da dieta reduz as perdas fecais de N e a produção de leite. As BP superestimam o fluxo microbiano, especialmente das BAL, pela presença de BP de origem dietética. A suplementação lipídica afeta a relação entre as estimativas de fluxo de BAP utilizando 15N e BP, levando à baixa correlação entre as estimativas com as duas técnicas. A recuperação urinária dos DP foi extremamente variável e aumentou com o aumento do nível de PDR da dieta. As excreções de creatinina e a excreção endógena de DP não são afetadas pela suplementação lipídica e pelo teor de PDR da dieta. A suplementação lipídica afeta consideravelmente o consumo e fluxo omasal de ácidos graxos, assim como o perfil lipídico dos microrganismos e o perfil de ácidos graxos do leite. Apesar de potencialmente aumentar o fluxo de alguns ácidos graxos insaturados e reduzir a extensão de bio-hidrogenação do C18:1 e C18:3, nas dietas sem SCAG, o nível de PDR tem poucos efeitos sobre o perfil de ácidos graxos das bactérias e do leite. / This study aimed to evaluate the effects of calcium salts of fatty acids (CSFA) addition and different levels of rumen degradable protein (RDP) in the diet of dairy cows on: feed intake, ruminal fermentation and nitrogen metabolism, productive performance and nitrogen balance; microbial protein synthesis estimates using 15N and purines basis (PB) as microbial markers, composition of bacterial pellets, urinary recovery of purines derivatives (PD) and endogenous PD excretion; omasal flow of fatty acids (FA), the bio-hydrogenation extent and FA profile of bacteria. Eight lactating, multiparous and rumen cannulated cows were used in a replicated 4 × 4 Latin square design, with a 2 × 2 factorial arrangement of treatments. The treatments were obtained by the combination of CSFA addition (-CSFA: without supplementation, and +CSFA: with 3.32% CSFA per kg dry matter - DM) and the RDP level (LRDP: low RDP, with 9.8% MS of RDP, and HRDP, high RDP: with 11.0% RDP of diet DM). Fat supplementation reduced (P &le; 0.049) feed intake, while tended (P = 0.076) to increase rumination time, and increased (P = 0.015) ruminal pH. In addition, CSFA supplementation decreased (P &le; 0.013) DM and organic matter ruminal digestibility, and tended (P &le; 0.096) to reduce NDF ruminal digestibility, and reduced (P = 0.043) N truly digested in the rumen. Besides negative effect (P = 0.039) on non-ammonia nitrogen (NAN) associated with large phase, CSFA showed no effect (P &ge; 0.634) on total NAN and microbial NAN flow, and increased (P = 0.032) microbial efficiency. Animals fed CSFA had higher (P = 0.043) milk yield, with lower (P &lt; 0.001) fat content, and improved (P &lt; 0.001) feed efficiency and N usage efficiency, in relation to those animals fed with non-supplemented diets. Animals fed LRDP tended to show higher (P &le; 0.096) CP intake, and acetate to propionate ruminal ratio, in relation to animals fed HRDP. In addition, HRDP increased (P &le; 0.048) starch total tract apparent digestibility and ruminal truly digestibility of N. The level of RDP showed no effect (P &ge; 0.719) on microbial N synthesis and microbial efficiency, and lower RDP level increased (P &le; 0.055) milk yield and decreased milk protein content. Decreased RDP level tended (P = 0.074) to reduce N fecal excretion, and increased (P = 0.021) fractional urinary excretion. Particle-associated bacteria (PAB) showed lower (P &le; 0.008) enrichment with 15N and purines N to total microbial N ratio, than liquid associated bacteria (LAB). Purine basis overestimated (P &le; 0.002) microbial flow, especially LAB flow. However, there was interaction (P = 0.067) between the effects of marker and lipid supplementation on PAB flow. In diets containing CSFA, PB and 15N showed similar (P > 0.05) estimates, whereas in the absence of CSFA, PB underestimated (P &le; 0.05) PAB flow, in relation to 15N. Increased dietary RDP levels tended (P = 0.061) to reduce omasal PB flow and decreased (P = 0.007) it\'s urinary recovery. Urinary recovery of PD was extremely variable (33.9% variation coefficient). Different evaluated factors had no effect (P &ge; 0.108) on urinary excretion of creatinine, and PD of endogenous origin. Daily excretions of creatinine and endogenous PD were 0.262 mmol/kg and 640 mmol/0.75, respectively. Higher RDP level resulted in reduced (P &lt; 0.001) C4:0, C12:0, C14:0, C16:0 and C18:0 FA intake, and tended (P = 0.068) to reduce C18:1 trans intake. There was an interaction (P &le; 0.095) between effects of the RDP and CSFA on the omasal flow of total FA and some specific FA (C15:0, C16:0, C17:0, C18:0, C18:1 cis-9, C18:2 cis-9 cis-12, C18: 3 cis and C22:0). This interaction occurred due to the higher (P &le; 0.05) omasal flow as consequence of increased RDP level, in the diets without CSFA. In diets containing CSFA, no effect (P &gt; 0.05) of the RDP level was observed on the omasal flow of FA. Consequently, the increase of RDP reduced (P &le; 0.05) the bio-hydrogenation extent of these FA in the diets -CSFA, with no effects (P &gt; 0.05) on the diets +CSFA. The addition of CSFA increased (P &le; 0.001) C18:2 bio-hydrogenation extent, as well as FA content of bacterial pellets. Dietary level of RDP had no effect (P &ge; 0.116) on microorganisms and milk FA profile. The addition of CSFA decreased or tended (P &le; 0.080) to decrease the levels of C15:0, C16:0, C16:1, C17:0 and C18:0 FA, while increased (P &le; 0.005) the concentrations of 18-carbon unsaturated fatty acids in the microorganisms. In addition, CSFA reduced (P &le; 0.009) the concentration of all FA lower than 18 carbons, saturated and unsaturated ratio in milk fat, and increased (P &le; 0.001) the concentrations of FA with 18 carbons or more, as well as unsaturated fatty acids. Thus, CSFA dietary addition decreases feed intake, increases rumination time, microbial efficiency, and milk yield. Higher level of RDP reduces N fecal losses and milk yield, and increases urinary losses of N. Purine basis overestimate microbial flow, especially LAB flow, by the presence of PB of dietary origin. Lipid supplementation affects the relationship between PAB flow estimates using 15N and PB, leading to a low correlation between the estimates with the two techniques. The urinary recovery of the PD was extremely variable and increased with the increase of the dietary RDP level. Creatinine excretions and endogenous excretion of PD are not affected by evaluated treatments. Lipid supplementation affects FA intake and omasal flow, as well as microorganisms and the milk FA profile. Although potentially increase the flow of some unsaturated FA and reduce the extent of bio-hydrogenation of C18:1 and C18:3 FA in the diets without CSFA, the level of RDP has no effects on microorganisms and milk FA profile.
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Μελέτη της συσσωμάτωσης εδαφών μέσω in situ καταβύθισης ανόργανων αλάτων ασβεστίου

Λιόλιου, Μαρία 11 March 2009 (has links)
- / Calcium salts are known as compounds and minerals and they have been extensively studied due to their rich morphology and applications. They are known as biominerals, cement additives. fillers, food additives etc. In the oil and gas production calcium sulfates, carbonates and silicates form tenaciously adhering scale deposits which may stop production if the problem is not tackled timely. The motivation for this work was the well known problem of sand production during oil recovery, which occurs when the production rate exceeds a critical value. The aim has been an attempt to develop an inexpensive and environmentally friendly method to consolidate soil and sand for building purposes. The work included in this thesis, is focused in the investigation of the physico-chemical conditions at which calcium salts precipitate acting as consolidating material for soil and sand. The marked differences in the physicochernical properties of the precipitating salts enabled us to investigate the relative efficiency of three different classes of calcium salts: sulfates, carbonates and phosphates. As a result. the present thesis is divided in three parts. In the first one, the spontaneous precipitation of calcium sulfate from supersaturated solutions and the inhibition by water soluble polymers was examined. Two kinds of polymers: three polyacrylates (PAA) with different molecular weights (2.000 (PAA1), 50,000 (PAA2) and 240.000 (PAA3)) and one co-polymer of polyacrylic with polystyrene sulfonate (PAA-PSS) were tested. Very low concentrations of all polymers tested, down to 6ppm, increased markedly the induction period preceding precipitation at supersaturations in which, in the absence of additives the precipitation was spontaneous. The “kinetic Langinuir” equation based on the assumption of Langmuir - type adsorption of the additives on the precipitating calcium sulfate dihydrate, gave satisfactory fit of the kinetic data. From the fit according to this model, the affinity constants for the polymer-gypsum surfaces were calculated. The order of the affinity was PSS>PAA3>PAA1>PAA2. The precipitation of calcium sulfate dihydrate in the presence of sand grains, resulted in crystals which formed weak bridges among the grains and the material in which precipitation took pace was rather poorly consolidated. The second part reports on the precipitation of calcium carbonate through the enzymatic production of carbonate ions. This newly proposed method is based upon the slow evolution of the supersaturation with respect to calcium carbonate in an aqueous environment, in which one of the components of the supersaturated solution (in our case carbonate) is slowly released by a source through the action of enzymes present in the aqueous medium. The work done concerning the development of the methodology of enzyme mediated calcium carbonate formation in aqueous media involved the following steps: (i) Investigation of the mechanism of urea (substrate) decomposition in the presence of jack bean urease (enzyme) through conductivity measurements. Urease exhibited a bell- shaped activity profile as a function of temperature with optimum value at 50CC. The reaction of urea decomposition in the presence of urease followed Michaelis-Menten type kinetics up to a concentration of about 250 mM. At concentrations exceeding 250 m.M, the reaction rate decreased as the carbonate source concentration increased, suggesting substrate inhibition. (ii) The effect of various parameters, such as temperature, enzyme and salts concentrations, the presence of sand etc. was studied upon the rate of precipitation and the morphology of the precipitate. The rate of precipitation increased with increasing temperature up to the optimum temperature of the enzyme activity. The experimental conditions identified through a series of batch type experiments were optimized for the consolidation of granular materials. Lab experiments done in loose sand packs have shown that consolidation may be achieved through bridges of calcium carbonate formed enzymatically. The consolidation efficiency was found to be strongly dependent on urease quality. Crude jack bean urease was more effective than refined one, due to impurities which promote calcitic rhombohedra to precipitate. Increasing the number of solution injections resulted in increased strength and reduced permeability, as expected. Resistance to uniaxial strength was found to be inversely proportional with temperature. The highest values were obtained for precipitates formed on sand grains at 25:C. The initial concentration of the supersaturated solutions were also found to affect the degree of consolidation, because of the different precipitation rates (higher at higher supersaturations) and of the amount of the material precipitated on the grains, which again was more, the higher the solution supersaturation with respect to calcium carbonate. Next, the heterogeneous nucleation and growth of calcite was investigated both in unstable and stable solutions at supersaturations sufficiently low to allow for the measurement of induction times preceding the onset of precipitation. In the unstable regions the induction times were inversely proportional and the rates of precipitation increased with the solution supersaturation. The high order dependence of the rates of precipitation on the solution supersaturation suggested a polynucleation mechanism. Fit of the induction time-supersaturation data according to this model yielded a value of 49 mJ/m2 for the surface energy of the calcite nucleus forming. In the stable domain of the supersaturations, seeded growth experiments showed a second order dependence on the rates of crystal growth of calcite seed crystals, while quartz seed crystals failed to induce nucleation. Raising supersaturation to reach the unstable domain showed interesting features: calcite seed crystals yielded crystal growth kinetics compatible with the polynucleation model, without any induction time contrary to the quartz seed crystals that triggered secondary nucleation. The kinetics data in the latter case were consistent with the polynuclear model and the surface energy for the newly forming embryo was calculated equal to 13 mJ/m2, confirming the fact that the process is dominantly heterogeneous. In the third part of this dissertation an attempt is presented to apply the idea of enzymatic precipitation of salts to the case of calcium phosphate formation. For this purpose, two kinds of phosphatases were tested for their PO4/3 release capacity from polyphosphates. Each type of the enzyme functioned at a different pH, so that a wide pH-range was covered (5.50-9.80). A seven-fold increase in the enzyme concentration resulted in the increase of the hydrolytic substrate decomposition percentage from 38% to 82% at pH 5.50. At pH 9.80, increasing the amount of alkaline phosphatase by a factor of five, the percentage of hydrolytic decomposition increased from 800o to 100%. The temperature dependence of the enzymes’ activity allowed for the determination of the maximum rate and the Michelis-Menten constant. At 25oC, Rmax and Kmwere calculated equal to 3.2x104 mol/h and 2.15x l0 mol/l for acid phosphatase, while the values for alkaline phosphatase were 5.9x10 mol/h and 4.26x10-3 mol/l, respectively. The activation energies were calculated to be 31 and 74 kJ/mol for acid and alkaline enzymes respectively. In terms of precipitation, the enzymic hydrolysis method is applicable for concentrations of the substrate and of the cation of the precipitating salt lower than 0.05 mol/l. For higher concentrations, insoluble complexes of Ca-substrate were formed and the precipitation of calcium phosphate was not favored. The presence of sand promoted both precipitation and hydrolysis when acid phosphatase was used, while with alkaline phosphatase the effect of the presence of sand was negligible. Consolidation experiments conducted in loose sand packs indicated that this method may be applicable only to stabilize sand with a few applications of the working solution, since the amount of the precipitate is small for the concentration levels suggested by the results of the present work. For strong consolidation, and for the composition of the solutions suggested in this work, a large number of injections is needed.
8

Some phases of mineral metabolism in chickens Part I. Availability of calcium salts for bone formation and rickets prevention in chicks. Part II. Effect of feeding high amounts of soluble iron and aluminum salts on the availability of phosphorus. Part III. Studies on the calcium metabolism of laying hens /

Deobald, Harold J. January 1935 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1935. / Typescript. With this are bound: The effect of feeding high amounts of soluble iron and aluminum salts / H.J. Deobald and C.A. Elvehjem. Reprinted from American journal of physiology, vol. 111, no. 1 (Feb. 1935), p. 118-123 -- Availability of calcium salts for chicks / by H.J. Deobald, C.A. Elvehjem, E.B. Hart, and J.G. Halpin. Reprinted from Poultry science, vol. XV, no. 1 (Jan. 1936), p. 42-47. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Processamento do milho flint associado à suplementação de gordura sobre o desempenho e metabolismo de vacas em pastagem tropical / Corn grain processing associated with fat supplementation on performance and metabolism of dairy cows grazing a tropical pasture

Fernanda Batistel 25 June 2014 (has links)
O objetivo desse trabalho foi avaliar os efeitos associativos entre o processamento do milho flint e a suplementação de sais de cálcio de óleo de palma (SCOP) para vacas no início de lactação mantidas em pastagem sobre desempenho, metabolismo, variáveis ruminais e a cinética de fermentação. No Capitulo 2, o objetivo desse estudo foi determinar a cinética de degradação do capim elefante, e de concentrados com diferentes fontes de gordura e métodos de processamento de grãos. O concentrado contendo sais de cálcio de óleo de soja- SCOS reduziu o volume de carboidratos fibrosos em comparação ao concentrado controle e ao concentrado contendo sais de cálcio de óleo de palma-SCOP. O fornecimento de milho floculado permitiu aumentar o volume final de CNF, a taxa de degradação dos CNF, a taxa de degradação dos CF e reduzir o lagtime em comparação ao milho moído. No capitulo 3, o objetivo foi avaliar os efeitos associativos entre o processamento do milho flint e a suplementação de SCOP para vacas no início da lactação mantidas em pastagem tropical. Quarenta vacas receberam os seguintes tratamentos: a) milho moído sem adição de SCOP; b) milho moído com adição de 400 g de SCOP; c) milho floculado sem adição de SCOP; e d) milho floculado com adição de 400 g. Posteriormente ao período de fornecimento dos tratamentos (90 dias), o efeito residual desses foi avaliado até o 280° DEL. Não houve interação entre o processamento do milho e o fornecimento de SCOP para nenhuma das variáveis avaliadas. O milho floculado e o fornecimento de SCOP aumentaram em 7,7% e 16% a produção de leite, respectivamente. A utilização de milho floculado aumentou o teor de proteína do leite em 8,3% e o de caseína em 7,3% e reduziu o N ureico do leite em 25,8%. A suplementação de SCOP reduziu os ácidos graxos (AG) de cadeia curta, aumentou os AG saturados e não influenciou os AG poli-insaturados. O consumo de energia liquida foi aumentado em 6% e 4,3% quando do fornecimento de SCOP e milho floculado, respectivamente. A eficiência de uso do N foi maior para os tratamentos com milho floculado e permitiu maior aporte de AA para a glândula mamária. O fornecimento de SCOP e milho floculado permitiram um aumento de 12,7 e 4,6% na produção de leite total na lactação. No capitulo 4, os mesmos tratamentos do capítulo 3 foram aplicados para obter-se os parâmetros ruminais e metabólicos. Foram utilizadas 4 vacas canuladas no rúmen em delineamento de quadrado latino 4×4. As concentrações de acetato, propionato, butírico, isobutírico, isovalérico e a concentração total foram maiores quando do fornecimento de milho floculado em comparação ao milho moído. Além disso, a suplementação com milho floculado reduziu a relação acetato/propionato e a concentração ruminal de N-NH3. Não houve efeito do processamento e da suplementação com SCOP sobre pH médio, pH mínimo e máximo. No entanto, o tempo em que o pH esteve abaixo de 6,0 e abaixo de 6,2 foi maior para o milho floculado em comparação ao milho moído. / The aim of this study was to evaluate the associative effect between flint corn processing and supplementation with calcium salts of palm oil (CSPO) in early lactation grazing cows on performance, metabolism, ruminal variables and fermentation kinetics. In Chapter 2, the aim was to determine the degradation kinetics of elephant grass and concentrates with different fat sources and methods of grain processing. The concentrate containing calcium salts of soybean oil reduced the volume of fibrous carbohydrates compared to the control and the concentrate containing calcium salts of palm oil - CSPO. Steam-flaked corn increased the final volume of NFC, the degradation rate of NFC, the rate of degradation of fibrous carbohydrates and reduced lagtime compared to ground corn. In chapter 3, the associative effect between flint corn processing and CSPO supplementation was evaluated to dairy cows in early lactation grazing on tropical pasture. Forty cows received the following treatments: a) ground corn without CSPO; b) ground corn with CSPO; c) flaked corn with no CSPO; and d) flaked corn with CSPO. After the period treatments period (90 days), the residual effect of these has been reported until 280 DIM. There was no interaction between corn processing CSPO for the variables evaluated. Flaked corn and fat supplementation increased mil yield by 7.7% and 16%, respectively. Flaked corn increased milk protein content in 8.3% and casein in 7.3% and reduced milk urea N by 25.8%. The CSPO reduced short-chain fatty acids (FA) and increased saturated FA and did not influence polyunsaturated FA. The net energy intake was increased by 6% and 4.3% when CSPO and flaked corn were fed, respectively. The efficiency of N utilization was higher for treatments with flaked corn and allowed a greater supply of AA to the mammary gland. Feeding CSPO and flaked corn allowed an increase of 12.7 and 4.6 % in total milk yield during lactation. In chapter 4, the same treatments from chapter 3 were applied to obtain ruminal and metabolic parameters. Four cannulated cows were used in a 4 × 4 Latin square design. Concentrations of acetate, propionate, butyric acid, isobutyric, isovaleric and the total VFA concentration were higher for steam flaked corn compared with ground corn. Furthermore, feeding steam-flaked corn reduced the acetate/propionate ratio and ruminal NH3-N concentration. There was no effect corn processing and supplementation with CSPO on average pH, minimum and maximum pH. However, the time that the pH was below 6.0 and below 6.2 was higher for steam flaked corn compared with ground corn.
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Avaliação de dietas lipídicas fornecidas em duas frequências de suplementação na terminação de novilhas em pastejo /

Santana, Márcia Cristina Araújo. January 2010 (has links)
Resumo: Objetivou-se avaliar o efeito de suplementos lipídicos disponíveis em diferentes formas (soja em grão moído, óleo de soja, e sais de cálcio - SC) no consumo de matéria seca total; comportamento ingestivo; desempenho corporal; parâmetros de fermentação ruminal; características de carcaça; desenvolvimento e composição corporal; e na qualidade da carne de novilhas mantidas em pastagens de Brachiaria brizantha cv. Marandu suplementadas em duas frequências (diária ou segunda, quarta e sexta - SQS). O experimento foi realizado nos meses de julho a novembro de 2007. Foram utilizadas novilhas mestiças (1/4 Nelore x 1/4 Santa Gertrudis x 1/2 Braunvieh), alimentadas com três suplementos lipídicos na quantidade de 0,75% do peso corporal. Os dados foram analisados em delineamento inteiramente casualisados com os tratamentos em arranjo fatorial (3x2 - três suplementos lipídicos e duas frequências alimentares). O consumo de matéria seca total foi maior nos meses de agosto e outubro em relação ao mês novembro. Houve efeito das formas de fornecimento da fonte lipídica sobre o consumo em kg de matéria seca total, forragem e nutrientes. Durante o período seco e início das águas os animais obtiveram ganhos médios totais de 0,577g dia-1, que não foram influenciados pelas suplementos lipídicos e frequências de suplementação utilizadas. A redução na frequência de suplementação alterou o tempo de pastejo em função dos suplementos lipídicos. Não houve influência dos suplementos lipídicos e das frequências de suplementação sobre o balanço de compostos nitrogenados, na síntese e eficiência de proteína microbiana. Houve influência das formas de fornecimento dos suplementos lipídicos sobre os valores de pH ruminal. A menor frequência de suplementação proporcionou diferenças nas concentrações de nitrogênio amoniacal ruminal... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research aimed to evaluate total dry matter intake, feeding behavior, growth performance, rumen fermentation parameters; carcass characteristics, development and body composition, and meat quality responses of steers grazing Brachiaria brizantha cv. Marandu supplemented at two frequencies (daily or Monday, Wednesday and Friday - MWF), under different forms of lipid supplements (soybean grain, soybean oil, and calcium salts - CS). This research was conducted throughout a four month period during the dry season (July to November 2007). Crossbred heifers were used (1/4 Nellore x 1/4 Santa Gertrudis x 1/2 Braunvieh) fed with three lipid supplements in the amount of 0.75% of body weight. The experiment was completely random, using a 3x2 factorial arrangement (3 supplements and 2 supplementation frequencies). The total dry matter intake was higher in August and October compared to November. There was effect of the lipids forms supplied on total dry matter, forage and nutrients intake. During the dry season and beginning of the wet season the animals showed average daily gain of 0.577 g day-1, which were not affected by dietary lipid supplementation and frequencies used. The kind of lipid diet under reduction on the frequency of supplementation alter grazing time. There was no influence of diet lipid and frequencies supplementation on nitrogenous compounds, in the synthesis and efficiency of microbial protein. There was influence of the lipids forms diets on values of rumen pH. Supplementation provided under frequency differences in the concentrations of ammonia in the rumen. There was influence of the lipids forms diets on weight hot carcass, and weight and dress percentage. Supplementation with dietary lipids under different forms and frequencies does not provide differences in body composition... (Complete abstract click electronic access below) / Orientadora: Telma Teresinha Berchielli / Coorientador: Ricardo Andrade Reis / Banca: Alexandre Amstalden Moraes Sampaio / Banca: Ana Cláudia Ruggieri / Banca: Marco Antonio Alvares Balsalobre / Banca: Juliano José de Resende Fernandes / Doutor

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