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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.
261

Plasma amino acid and metabolite changes in pigs during endotoxemia

Price, Kathryn Leigh 12 January 2012 (has links)
The nutritional status, especially circulating amino acid (AA) levels, can drastically change during a non-infectious (i.e., LPS) or infectious (e.g., Salmonella) challenge. Thus, study 1 examined the effect of LPS treatment (N = 9, 26.9 ± 1.07 kg BW) on plasma AA and metabolite levels in pigs. Data were used to generate prediction equations establishing mathematical relationships between plasma AA levels and numerous blood metabolites (e.g., total lipid, LDL, HDL, blood urea nitrogen, etc). These equations have the potential to improve the nutritional treatment and recovery of acute and chronically ill patients. Study 2 (19.1 ± 0.37 kg) was a continuation of study 1 except the sampling time was increased from 12 to 24 h. One-half of the pigs in study 2 were treated with LPS (N=15) and the other one-half were saline treated control animals (N = 16). This design allows for monitoring changes in plasma AA and their catabolism in response to endotoxemia. Area under the curve (AUC) was calculated for a selected AA to report AA balances. During the induction phase of an acute challenge (t = -2 to 12 h), analyzed AA were in a negative balance indicating heavy AA catabolism. However, during the recovery phase (t = 12 to 24 h) half of the AA were in a positive balance while the other half were still negative. The ability of equations to accurately predict AA concentrations was tested. Results indicate poor performance possibly due to heavy term biases. Thus, it was concluded that equations need to be revisited and non-linear terms need to be evaluated. Nonetheless, routine clinical blood metabolites can be used to estimate plasma AA levels during immune activation. We successfully established a porcine Salmonella enterica serovar Typhimurium model. Pigs infected with Salmonella had a febrile response for 4 d and exhibited marked changes in their fecal bacterial populations Finally, we investigated plasma changes in N-τ-methyl histidine (NτMH) in healthy and LPS-treated pigs. NτMH— is a post-translationally modified AA that has historically been used as an indirect marker of muscle protein breakdown in rodents and humans. However, the major form (i.e., free or acetylated) of NτMH in pig plasma was unknown. Results indicate that only 15% of plasma NτMH is in the free form and the remainder is acetylated. Furthermore, LPS treated pigs had increased acetylated and total NτMH fractions while free NτMH did not change. Therefore, to accurately monitor plasma changes in NτMH as an indicator of muscle proteolysis, plasma samples must be subjected to acid hydrolysis. / Ph. D.
262

Evaluation of the novel P particle vaccine candidate against human norovirus using the gnotobiotic pig challenge model

Kocher, Jacob 10 December 2014 (has links)
Noroviruses (NoVs) are a cause of nonbacterial acute gastroenteritis affecting all ages. NoV infections result in over 200,000 pediatric deaths in developing countries annually. Vaccine development has been hindered by the lack of cell culture systems and small animal models; thus, vaccine development has relied upon recombinant VP1 capsid proteins, such as virus-like particles (VLPs) and P particles. P particles are a novel vaccine candidate derived from expression of the VP1 protruding (P) domain, while VLPs require expression of the full-length VP1. My studies utilize a gnotobiotic (Gn) pig model of human NoV infection and diarrhea to evaluate the protective efficacy and T cell responses induced by P particles and to compare them with prior NoV infection (NoVPO) and VLPs. Gn pigs received 100 µg of P particles (LoPP) or VLPs, 250 µg P particles (HiPP), or adjuvants only intranasally at post-inoculation day (PID) 0, 10, and 21. Monophosphoryl lipid A and chitosan were used as mucosal adjuvants. At PID 28, a subset of pigs were orally challenged with 10 median infectious doses (ID50) NoV. NoVPO, LoPP, HiPP, and VLPs provided partial protection from diarrhea (83%, 47%, 60%, and 60% protection rates, respectively). Only NoVPO and HiPP provided protection from shedding (49% and 60% protection rates, respectively) and also reduced the number of CD25- regulatory T cells (Tregs) in duodenum following challenge. NoV primary infection induced an overall pro-Treg and low, transient Th1 response. LoPP induced stronger overall T cell responses compared to VLPs, including activated CD4+ T cells and duodenal CD8+IFN-γ+ T cells, suggesting that P particles are more immunogenic than VLPs. I also evaluated the effects of simvastatin, a cholesterol-reducing drug that increases NoV infectivity, on P particle vaccine efficacy. Simvastatin abolished P particle-induced protection and significantly increased diarrhea severity. Simvastatin reduced total numbers of duodenal mononuclear cells, IFN-γ+ T cells pre-challenge, and Tregs post-challenge, indicating that simvastatin impairs development of immune system and immune responses. Findings from these studies elucidate potential mechanisms behind P particle-induced immunity and reveal the negative effects of simvastatin on NoV-induced protective immunity. The knowledge will facilitate the development of effective NoV vaccines. / Ph. D.
263

Complete Genome Sequence and Pathogenicity of Two Swine Parainfluenzaviruses Isolated from Pigs in the United States

Qiao, Dan 14 July 2009 (has links)
Members of the family Paramyxoviridae are non-segmented, negative-strand RNA viruses. A large and diverse host species are infected by paramyxoviruses, including avian, porcine, canine, bovine, equine, ovine, reptiles, aquatic species and humans. In the last few decades, many novel paramyxoviruses have emerged causing catastrophic illnesses in different aquatic and terrestrial species of animals and some of them also made the species jump to humans. Two novel paramyxoviruses 81-19252 (Texas81) and 92-7783 (ISU92) were isolated in the 1980s and 1990s from the brain of pigs that experienced respiratory and central nervous system disease from South and North Central United States. To understand their importance as swine pathogens, molecular characterization and pathogenicity studies were undertaken. The complete genome of Texas81 virus was 15456 nucleotides (nt) and ISU92 was 15480 nt in length consisting of six non-overlapping genes coding for the nucloeo- (N), phospho- (P), matrix (M, fusion (F), hemagglutinin-neuraminidase (HN) and large polymerase (L) proteins in the order 3'-N-P/C/V-M-F-HN-L-5'. The features related to virus replication and found to be conserved in most members of Paramyxoviridae were also found in swine viruses. These include: conserved and complementary 3â leader and 5â trailer regions, trinucleotide intergenic sequences, highly conserved gene start and gene stop signal sequences. The length of each gene of these two viruses was similar except for the F gene, in which ISU92 had an additional 24 nt "U" rich 3â untranslated region (UTR). The P gene of these viruses were predicted to express the P protein from the primary transcript and edit a portion of its mRNA to encode V and D proteins and the C protein was expected to be expressed from alternate translation initiation from the P gene as in Respiroviruses. Sequence specific features related to virus replication and host specific amino acid signatures in P, F, HN and L proteins indicated that these viruses probably originated from bovine parainfluenzavirus 3. Pairwise comparisons of deduced amino acid sequences of swine viral proteins with members of Paramyxoviridae and phylogenetic analysis based on individual genes as well as predicted amino acid sequences suggested that these viruses were novel members of the genus Respirovirus of the Paramyxovirinae subfamily and genotype A of bovine parainfluenzavirus type 3. The mild clinical signs and undetectable gross and microscopic lesions observed in swine parainfluenzavirus (sPIV3)-infected pigs indicate the inapparent nature of these viruses in pigs. Limited seroprevalence studies in serum samples collected from pig farms in Minnesota and Iowa in 2007-2008 by indirect ELISA revealed that sPIV3 are not circulating in these farms. The mild pathogenicity of sPIV3 can facilitate its development as a vaccine vector. The screening ELISA developed by us could be used to detect seroprevalence of sPIV3 in animal and human populations. / Master of Science
264

Effect of Cortisone Injections on Complement Titers of Guinea Pigs

Renshaw, Larry Alan 01 1900 (has links)
As complement is now believed to have some function in immunity it becomes of interest to determine what effect, if any, cortisone may have upon complement concentration in animal sera.
265

Altered protein and fatty acid composition of porcine follicular fluid due to a high fibre diet and the subsequent effects on oocyte maturation

Jarrett, Selene January 2018 (has links)
Background Ovarian follicular fluid serves as the microenvironment for a maturing oocyte prior to ovulation. Previous studies have shown that gilts fed a high fibre (HF) diet before ovulation have improved fertility compared to gilts fed a control (C) diet, including a higher proportion of metaphase II oocytes following in vitro maturation (IVM). Hypothesis The molecular composition of porcine follicular fluid (pFF) was altered by the diet and that these alterations conferred the fertility benefits. Aims The aim of this study was to compare the protein composition of pFF from pigs fed a control diet with pFF of pigs fed a high fibre diet, to identify whether a high fibre diet fed to pigs during their oestrous cycle altered the composition of pFF. Additionally, the pFF of fertile animals was compared with the pFF of non-fertile animals to identify whether pFF composition was associated with fertility; fertile animals produced an embryo following in vitro fertilisation (IVF). Differences in the molecular composition were to be used to ascertain the potential underlying mechanism(s) involved in dietary induced improvements to oocyte maturation. Results The protein composition of pooled pFF from 12 HF-pigs and 12 C-pigs was compared by liquid chromatography tandem mass spectrometry (LC-MS/MS). Additionally, within each dietary group, the composition of pooled pFF from pigs whose oocytes produced blastocysts following in vitro fertilisation (C-Bl and HF-Bl) was compared with pFF from pigs whose oocytes did not produce blastocysts (C-No and HF-No respectively; n=6 per group). These proteomic analyses identified differentially expressed proteins, associated with several canonical pathways including acute phase response signalling, complement system and LXR/RXR activation, as determined by Ingenuity Pathway Analysis. Quantitative western blots revealed the differential expression of candidates associated with these canonical pathways. Plasminogen expression was lower (P≤0.05) in pFF of HF-pigs compared to pFF of C-pigs. In pFF from C-Bl gilts, apolipoprotein A4 (P≤0.01) and apolipoprotein M (P≤0.05) expression were higher compared to pFF from C-No gilts. Plasmin expression was lower (P≤0.05) in pFF from HF-Bl gilts compared to pFF from C-Bl gilts. Due to the interest in the differentially expressed apolipoproteins (involved in cholesterol and lipid efflux), a targeted metabolomic analysis was carried out to measure the concentration of nine fatty acids (FAs) in pFF of individual pigs in C-No, C-Bl, HF-No, HF-Bl groups (n=6 per group); adrenic, arachadonic, arachidic, dihomo- γ-linolenic, docosapentaenoic, erucic, linoleic, palmitoleic and oleic acids were measured by LC-MS/MS. The analysis revealed the lower concentration of linoleic acid (LA, p≤0.05) and higher concentration of erucic acid (P≤0.05) in HF-pFF compared to C-pFF. Following the results of the targeted metabolomic analysis, cumulus-oocytecomplexes (COCs) were matured in TCM 199 medium supplemented with 0 (No-LA), 50, 100 or 200 μM LA for 44 hours (n = 320 per treatment). COC diameters were measured and the COCs were categorised into "full", "partial" or "no" expansion. COCs were denuded, fixed and stained to determine their stage of maturation. IVM with 200 μM LA resulted in the reduced diameter of COCs (p≤0.01), fewer COCs with full cumulus expansion (p≤0.05) and fewer metaphase II oocytes (p≤0.05). Discussion Plasminogen is the precursor to plasmin, a proteolytic enzyme involved in weakening the follicular wall prior to ovulation. The lower expression of plasminogen and plasmin in pFF of high fibre pigs implies a delay in the accumulation of the inflammatory proteins required for ovulation. The delay in ovulation can result in the lengthening of the oocyte maturation process, leading to more mature oocytes, as observed in the previous studies. A disruption in the expression of apolipoproteins may also occur in high fibre-fed pigs. The increase in apolipoproteins associated with blastocyst development was only observed with pFF of control pigs but not high fibre pigs. An alteration in lipid homeostasis in the high fibre pigs could potentially affect oocyte energy consumption. LA concentration was also lower in pFF of high fibre pigs. LA is an essential fatty acid, indicating that the difference in concentration is directly from the diet. The lower levels of LA can potentially be beneficial to oocyte maturation, which is substantiated by the negative effects of a high LA concentration on IVM of abattoir derived oocytes.
266

Direct and correlated responses to selection in large white pigs for growth rate on restricted feeding

Nguyen Hong Nguyen, Nguyen Unknown Date (has links)
Responses in growth rate, food conversion efficiency, carcass composition, residual food intake, meat quality and reproduction traits to selection in pigs for four years, for high or low post-weaning growth rate on a fixed but restricted ration were measured in progeny grown on either restricted, ad libitum individual or ad libitum group feeding regimens. Genetic and phenotypic correlations among the traits were also examined on animals whose full pedigrees comprised a total of 5324 animals. Substantial divergent response was achieved from selection for high vs. low growth rate on restricted feeding, with the genetic means of daily gain diverging by 81.25 g or 2.78 genetic standard deviations (SigmaG). The high and low growth rate lines also differed in ultrasonic backfat and food conversion efficiency by 1.12 SigmaG and 0.84 SigmaG, and by 0.88 SigmaG, 1.10 SigmaG, and 1.14 SigmaG for carcass weight daily gain, carcass fat and lean percentage, respectively. These responses were consistent with the moderately to highly, favourable genetic correlations among and between performance and carcass composition traits. Genetic changes in growth rate, ultrasonic backfat, food conversion ratio, carcass daily gain, carcass fat and lean percentage when measured on ad libitum individual feeding were all economically beneficial. The high growth line had a significantly lower voluntary daily food intake and residual food intake than the contemporaneous low line, indicating a reduced energy requirement for maintenance in the high relative to the low line. Genetic correlations between either growth rate or backfat and carcass traits were favourable but unfavourable between daily food intake and carcass fat or lean percentage, implying that selection strategies which place emphasis on increased leanness and decreased fatness would result in a decline in voluntary food intake of the animals. The descendants of breeding pigs selected for high post-weaning daily gain on restricted feeding showed significantly increased growth rates, slaughter weights and carcase lean percentages and reduced fatness when grown in group housing with ad libitum feeding. This suggests that restricted feeding is an effective performance testing approach for seedstock lines supplying commercial regimens with group housing and ad libitum feeding. Carcase lean pH values measured 24 hours post-mortem (pH24) were not statistically different between the selected lines, suggesting that an increase in basal metabolic rate due to increased rate of lean deposition in the high relative to the low line may have been compensated for by a reduction in heat production from other sources such as physical activity. Such a reduction was evidenced by a lower residual food intake in the high than the low growth lines. This supports the hypothesis that selection for high growth rate on restricted feeding does not have detrimental effects on pork quality. The sows of the high growth line produced more piglets with significantly heavier weights at birth, giving a potential for better post-natal growth and higher yield of pork weaned per sow per year than the low growth sows. Body weights of the high line sows prior to mating were also significantly higher than those of low line sows suggesting earlier age of sexual maturity. A non-significant tendency for high line sows to have a lower voluntary food intake than low line sows pointed to the possibility that their lower maintenance requirement as growers was carried over to the lactational phase of life. It is concluded that selection for high growth rate on a restricted ration of fixed amount will produce pig strains with a high genetic potential for lean growth, reduced energy requirement for maintenance and improved reproductive performance, and which will be suitable for growing under a wide range of commercial feeding environments.
267

Direct and correlated responses to selection in large white pigs for growth rate on restricted feeding

Nguyen Hong Nguyen, Nguyen Unknown Date (has links)
Responses in growth rate, food conversion efficiency, carcass composition, residual food intake, meat quality and reproduction traits to selection in pigs for four years, for high or low post-weaning growth rate on a fixed but restricted ration were measured in progeny grown on either restricted, ad libitum individual or ad libitum group feeding regimens. Genetic and phenotypic correlations among the traits were also examined on animals whose full pedigrees comprised a total of 5324 animals. Substantial divergent response was achieved from selection for high vs. low growth rate on restricted feeding, with the genetic means of daily gain diverging by 81.25 g or 2.78 genetic standard deviations (SigmaG). The high and low growth rate lines also differed in ultrasonic backfat and food conversion efficiency by 1.12 SigmaG and 0.84 SigmaG, and by 0.88 SigmaG, 1.10 SigmaG, and 1.14 SigmaG for carcass weight daily gain, carcass fat and lean percentage, respectively. These responses were consistent with the moderately to highly, favourable genetic correlations among and between performance and carcass composition traits. Genetic changes in growth rate, ultrasonic backfat, food conversion ratio, carcass daily gain, carcass fat and lean percentage when measured on ad libitum individual feeding were all economically beneficial. The high growth line had a significantly lower voluntary daily food intake and residual food intake than the contemporaneous low line, indicating a reduced energy requirement for maintenance in the high relative to the low line. Genetic correlations between either growth rate or backfat and carcass traits were favourable but unfavourable between daily food intake and carcass fat or lean percentage, implying that selection strategies which place emphasis on increased leanness and decreased fatness would result in a decline in voluntary food intake of the animals. The descendants of breeding pigs selected for high post-weaning daily gain on restricted feeding showed significantly increased growth rates, slaughter weights and carcase lean percentages and reduced fatness when grown in group housing with ad libitum feeding. This suggests that restricted feeding is an effective performance testing approach for seedstock lines supplying commercial regimens with group housing and ad libitum feeding. Carcase lean pH values measured 24 hours post-mortem (pH24) were not statistically different between the selected lines, suggesting that an increase in basal metabolic rate due to increased rate of lean deposition in the high relative to the low line may have been compensated for by a reduction in heat production from other sources such as physical activity. Such a reduction was evidenced by a lower residual food intake in the high than the low growth lines. This supports the hypothesis that selection for high growth rate on restricted feeding does not have detrimental effects on pork quality. The sows of the high growth line produced more piglets with significantly heavier weights at birth, giving a potential for better post-natal growth and higher yield of pork weaned per sow per year than the low growth sows. Body weights of the high line sows prior to mating were also significantly higher than those of low line sows suggesting earlier age of sexual maturity. A non-significant tendency for high line sows to have a lower voluntary food intake than low line sows pointed to the possibility that their lower maintenance requirement as growers was carried over to the lactational phase of life. It is concluded that selection for high growth rate on a restricted ration of fixed amount will produce pig strains with a high genetic potential for lean growth, reduced energy requirement for maintenance and improved reproductive performance, and which will be suitable for growing under a wide range of commercial feeding environments.
268

Direct and correlated responses to selection in large white pigs for growth rate on restricted feeding

Nguyen Hong Nguyen, Nguyen Unknown Date (has links)
Responses in growth rate, food conversion efficiency, carcass composition, residual food intake, meat quality and reproduction traits to selection in pigs for four years, for high or low post-weaning growth rate on a fixed but restricted ration were measured in progeny grown on either restricted, ad libitum individual or ad libitum group feeding regimens. Genetic and phenotypic correlations among the traits were also examined on animals whose full pedigrees comprised a total of 5324 animals. Substantial divergent response was achieved from selection for high vs. low growth rate on restricted feeding, with the genetic means of daily gain diverging by 81.25 g or 2.78 genetic standard deviations (SigmaG). The high and low growth rate lines also differed in ultrasonic backfat and food conversion efficiency by 1.12 SigmaG and 0.84 SigmaG, and by 0.88 SigmaG, 1.10 SigmaG, and 1.14 SigmaG for carcass weight daily gain, carcass fat and lean percentage, respectively. These responses were consistent with the moderately to highly, favourable genetic correlations among and between performance and carcass composition traits. Genetic changes in growth rate, ultrasonic backfat, food conversion ratio, carcass daily gain, carcass fat and lean percentage when measured on ad libitum individual feeding were all economically beneficial. The high growth line had a significantly lower voluntary daily food intake and residual food intake than the contemporaneous low line, indicating a reduced energy requirement for maintenance in the high relative to the low line. Genetic correlations between either growth rate or backfat and carcass traits were favourable but unfavourable between daily food intake and carcass fat or lean percentage, implying that selection strategies which place emphasis on increased leanness and decreased fatness would result in a decline in voluntary food intake of the animals. The descendants of breeding pigs selected for high post-weaning daily gain on restricted feeding showed significantly increased growth rates, slaughter weights and carcase lean percentages and reduced fatness when grown in group housing with ad libitum feeding. This suggests that restricted feeding is an effective performance testing approach for seedstock lines supplying commercial regimens with group housing and ad libitum feeding. Carcase lean pH values measured 24 hours post-mortem (pH24) were not statistically different between the selected lines, suggesting that an increase in basal metabolic rate due to increased rate of lean deposition in the high relative to the low line may have been compensated for by a reduction in heat production from other sources such as physical activity. Such a reduction was evidenced by a lower residual food intake in the high than the low growth lines. This supports the hypothesis that selection for high growth rate on restricted feeding does not have detrimental effects on pork quality. The sows of the high growth line produced more piglets with significantly heavier weights at birth, giving a potential for better post-natal growth and higher yield of pork weaned per sow per year than the low growth sows. Body weights of the high line sows prior to mating were also significantly higher than those of low line sows suggesting earlier age of sexual maturity. A non-significant tendency for high line sows to have a lower voluntary food intake than low line sows pointed to the possibility that their lower maintenance requirement as growers was carried over to the lactational phase of life. It is concluded that selection for high growth rate on a restricted ration of fixed amount will produce pig strains with a high genetic potential for lean growth, reduced energy requirement for maintenance and improved reproductive performance, and which will be suitable for growing under a wide range of commercial feeding environments.
269

An?lise tribol?gica de um sistema de acionamento alternativo de pigs para a ind?stria do petr?leo

Medeiros, Suelson Di?genes de Fran?a 23 September 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:04Z (GMT). No. of bitstreams: 1 SuelsonDFM_DISSERT.pdf: 3898058 bytes, checksum: 85578e98eca2ae4f89d7ebd20d9c5e06 (MD5) Previous issue date: 2010-09-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / It is analyzed through the concepts of tribology and mechanical contact and damage the suggestion of implementing a backup system for traction and passage of Pipeline Inspection Gauge (Pig) from the inside of pipelines. In order to verify the integrity of the pipelines, it is suggested the possibility of displacement of such equipment by pulling wires with steel wires. The physical and mechanical characteristics of this method were verified by accelerated tests in the laboratory in a tribological pair, wire versus a curve 90. It also considered the main mechanisms of wear of a sliding system with and without lubricant, in the absence and presence of contaminants. To try this, It was constructed a test bench able to reproduce a slip system, work on mode back-and-forth ("reciprocation"). It was used two kinds of wires, a galvanized steel and other stainless steel and the results achieved using the two kinds of steel cables were compared. For result comparative means, it was used steel cables with and without coating of Poly Vinyl Chloride (PVC). The wires and the curves of the products were characterized using metallographic analysis, microhardness Vickers tests, X-ray diffraction (XRD), X-Ray Refraction (XRF) and tensile tests. After the experiments were analyzed some parameters that have been measurable, it demonstrates to the impracticality of this proposed method, since the friction force and the concept of alternating request at the contact between the strands of wire and the inner curves that are part ducts caused severe wear. These types of wear are likely to cause possible failures in future products and cause fluid leaks / Analisa-se, por interm?dio dos conceitos da tribologia e da mec?nica do contato e do dano, a sugest?o de implanta??o de um sistema alternativo para tracionamento e passagem de Pipeline Inspection Gauge (Pig) pelo interior de dutos. Com o intuito de verificar a integridade dos dutos, sugere-se a possibilidade de realizar o deslocamento destes equipamentos atrav?s de tracionamento com fios de arames de a?o. ?s caracter?sticas mec?nicas e f?sicas deste m?todo proposto foram verificadas atrav?s de ensaios acelerados em laborat?rio, em um par tribol?gico, arame versus uma curva de 90?. Estudam-se tamb?m, os principais mecanismos de desgastes de um sistema deslizante, com e sem lubrificante, na aus?ncia e na presen?a de contaminantes. Para esse fim foi constru?da uma bancada de ensaio para testes em laborat?rio, capaz de reproduzir um sistema de deslizamento, com movimento alternado em modo de vai-e-vem ( reciprocation ). Foram utilizados dois tipos de fios de arame, um de a?o galvanizado e outro de a?o inoxid?vel. Utilizou-se como forma comparativa de resultados cabos de a?os com e sem revestimento de Poli Cloreto de Vinila (PVC). Os fios de arame e as curvas dos dutos foram caracterizados atrav?s de an?lise metalogr?fica, an?lise de microdureza Vickers, dos ensaios de difra??o de raios-x (XRD), refra??o de raios-x (XRF), e de ensaios de tra??o. Ap?s a realiza??o dos ensaios analisam-se alguns par?metros que foram mensur?veis e evidencia-se o processo de desgaste por Delamina??o entre os pares tribol?gicos envolvidos. Associa-se essa forma de desgaste a for?a de atrito e a concep??o da solicita??o alternada no contato entre os fios de arames e a parede interna das curvas que fazem parte dos dutos. Estes tipos de desgastes ir?o ocasionar poss?veis falhas nos dutos e originar futuros vazamentos de fluidos
270

Diferentes padrões de divisões de sexos para alojamento de suínos criados em sistema "wean to finish" / Different patterns of gender divisions for housing swine reared in "wean to finish" system

Massari, Juliana Maria, 1987- 25 August 2018 (has links)
Orientadores: Daniella Jorge de Moura, Douglas D'Alessandro Salgado / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-25T22:25:38Z (GMT). No. of bitstreams: 1 Massari_JulianaMaria_M.pdf: 1764444 bytes, checksum: 4c263e9b2842e904bef162cd308829b6 (MD5) Previous issue date: 2014 / Resumo: O Brasil é um dos maiores produtores de carne suína do mundo, e almeja sempre por avanços a fim de estabelecer-se e conquistar novos mercados consumidores. O "wean to finish" é um sistema de criação de suínos, na qual os animais permanecem em uma mesma instalação do desmame até a fase de abate. Ainda não existem muitos estudos que definam qual o melhor padrão de divisões de sexo para alojamento de suínos criados neste sistema visando o bem-estar e a produtividade. Assim, objetivou-se estudar o alojamento exclusivo de 26 machos suínos (T1), misto (T2), contendo 13 machos e 13 fêmeas, e o tratamento único de fêmeas (T3) para os quesitos de ganho de massa, variáveis comportamentais e ambientais. Para análise dos dados foi utilizado às análises estatísticas descritivas, exploratórias e confirmatórias (teste de Kruskall-Wallis), através do programa estatístico Minitab. Foram obtidas diferenças no ganho de massa entre as diferentes condições de alojamento ao longo das fases de criação. Os resultados analisados das variáveis comportamentais também indicaram diferenças entre os tratamentos. Já com relação às variáveis ambientais, não foram obtidas diferenças significativas / Abstract: Brazil is one of the largest pork producers in the world, and always craves advances in order to establish themselves and gain new consumer markets. The "wean to finish" is a system of pig farming, where animals remain in an installation phase from weaning to slaughter. There are not many studies that define what the best pattern of divisions sex for housing pigs created this system for the well - being and productivity. Thus, we aimed to study the exclusive property of 26 male pigs (T1) , mixed (T2) , containing 13 males and 13 females , and females only treatment (T3) for questions of mass gain , behavioral and environmental variables . Data analysis was used to descriptive, exploratory and confirmatory statistical analysis (Kruskal - Wallis test) , through the Minitab statistical program . Differences were obtained in mass gain between the different housing conditions throughout the stages of creation. Analyzed the results of the behavioral variables also indicated differences between treatments. In relation to environmental variables, no significant differences were obtained / Mestrado / Construções Rurais e Ambiencia / Mestra em Engenharia Agrícola

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