Master of Science / Department of Animal Sciences and Industry / Jim L. Nelssen / Five-hundred and four barrows and gilts were used in four experiments to determine the influence of dietary ingredients on fat quality. Experiment 1 evaluated feeding duration of choice white grease (CWG) and soybean oil. Increasing feeding duration of pigs fed CWG or soybean oil increased (quadratic, P < 0.01) iodine value (IV) in jowl fat and backfat. Pigs fed soybean oil had increased (P < 0.01) IV in jowl and backfat compared with pigs fed CWG. In Exp. 2 dried distillers grains with solubles (DDGS), extruded expelled soybean meal (EESM), and CWG were used to evaluate diets with common iodine value product (IVP) from ingredients varying in unsaturated fat level and concentration. Pigs fed either diet with DDGS had increased (P = 0.02) backfat and jowl fat IV, compared with all other treatments. Pigs fed EESM had increased (P = 0.04) backfat and jowl fat IV compared with the control, low CWG, and high CWG. Pigs fed low CWG and high CWG had increased (P = 0.04) jowl fat IV compared to the control. Increasing dietary fat increased carcass fat IV, with unsaturated fats from DDGS and EESM having a greater affect than more saturated fats, such as CWG, even when formulated to the same IVP. Experiment 3 evaluated the effects of increasing CWG in corn- and sorghum-based diets on fat quality. There was a grain source X fat level interaction (P = 0.04) for IV in both backfat and jowl fat. Adding CWG increased IV in backfat and jowl fat for pigs fed corn- and sorghum-based diets; however, the greatest increase was between 0 and 2.5% CWG in sorghum-based diets and between 2.5 and 5% CWG in corn-based diets. Despite this interaction, pigs fed corn-based diets had increased (P < 0.01) backfat and jowl fat IV compared with pigs fed sorghum-based diets. Increasing CWG increased (linear, P < 0.01) IV in backfat and jowl fat. Experiment 4 examined the effects of DDGS on fat quality. Backfat, jowl fat, and belly fat IV increased (linear, P = 0.02) with increasing DDGS in both the pigs marketed on d 57 and 78.

The state of diseases in South African domestic pigs drastically changed when Porcine reproductive and respiratory syndrome (PRRS) was introduced in the Western Cape Province during 2004 and was followed by an outbreak of Classical swine fever (CSF), primarily in the Eastern Cape, in 2005. These outbreaks occurred mostly in rural and backyard pig populations. Subsequent to an intensive culling operation, it became necessary to implement country-wide surveillance to substantiate that freedom from these two diseases had been achieved. Samples for a country-wide cross-sectional study were collected from commercial and non-commercial pig establishments in a combined effort between the South African Pig Producers Organisation (SAPPO) and the National and Provincial Departments of Agriculture, Veterinary Services. The survey targeted the high-risk sector of the pig population and included rural pig populations, pigs from “grey” herds (commercial farms with inadequate bio-security) and commercial establishments. Samples were also tested for Swine influenza (SI), Transmissible gastroenteritis (TGE), Aujeszky’s Disease (Aujeszky’s), Foot-and-mouth Disease (FMD) and African swine fever (ASF). The first objective of this study was to evaluate the validity of the survey design. The second objective was to evaluate the results and, thereafter, make valid inferences regarding the disease status of the domestic pig population. This also included the confidence level of the overall survey. The third objective was to qualify and quantify sample losses to enable improved future survey design and execution. The outcome of the survey indicated that the results were sufficient to conclude that the non-commercial pig population is free from CSF, PRRS and SI at the expected minimum prevalence of 1%. The calculations also indicated that the results were adequate to conclude that the commercial pig population is free from CSF, PRRS and SI at the expected minimum prevalence of 5%. The outcome of the calculations done on the second phase test results allows South Africa to conclude that the non-commercial pig sector is free from FMD, ASF, Aujeszky’s and TGE, at the expected minimum prevalence of 2%. The sample sizes for Aujeszky’s, TGE, ASF and FMD tests in the commercial sector were too small to allow for a decision to be made and, as a result, it was not possible to declare this sector free of disease. However, the non-commercial sector is much larger and the risk of disease introduction higher, therefore, if the non-commercial sector tested negative for the disease, it is highly likely that the commercial sector will be free of the disease as well. It is recommended that passive surveillance be augmented and that a national pig survey be conducted every 3 years to provide proof of disease freedom. It is important to conduct a risk analysis to qualify and quantify the risk of CSF and PRRS introduction. This could improve future surveys by providing a scientific basis for targeted surveillance. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Production Animal Studies / unrestricted

Calcium transport across the placenta is asymmetrical and is believed to be an active transport. An essential step in such a transport is translocation of the ion across a single plasma membrane. The objective of this thesis was to study the Ca2+ -related properties of the placental plasma membranes and to gain some knowledge of their role in Ca2+ -transport. Three Ca2+ -related properties were studied: 1. Ca2+ -binding to the placental plasma membranes; 2. The membrane bound enzyme Ca -ATPase; and 3. Ca2+ -uptake by the placental plasma membrane vesicles. Ca2+ -binding properties of the membrane preparation were studied by the use of a new method, the flow dialysis system. Two types of sites for Ca were found: 1) high affinity, low capacity sites, and 2) low affinity, high capacity sites. The high affinity sites had 10-fold higher affinity for Ca2+ than for Mg2+ . A calcium-stimulated, membrane-bound enzyme, namely Ca2+ -ATPase, was located in the placental plasma membranes. This enzyme is distinct from the Na+, K+-ATPase and alkaline phosphatase. The enzyme can be activated by Mg2+ but with lower efficiency. Both Ca2+ and Mg2+ activate the enzyme at the same site. A formula was derived, enabling one to predict very precisely the velocity of the enzyme incubated under any combination of Ca2+ and Mg2+ ; this relationship is presented in a three dimensional model. The formula can be used for other enzymes or other substrates, as was demonstrated with ATP and ADP. The placental plasma membrane vesicles are capable of accumulating Ca2+ . Ca2+ -uptake was defined as the amount of Ca2+ which is not available for rapid exchange and cannot be displaced by a high concentration of competitor in the presence of ATP. This definition is different from and more accurate than the one which is widely used and cited in the literature. An intravesicular Ca2+ concentration of 190 mM was recorded, which was 24-fold higher than the external Ca2+ concentration (8 mM). Ca2+ -uptake was dependent on ATP hydrolysis by the placental Ca2+ -ATPase. This process was independent of Mg2+ . It is suggested that while the substrate for Ca2+ -ATPase is Ca-ATP, the substrate for Ca2+ -uptake is Ca2+. The overall Ca2+ -related properties of the placental plasma membranes are independent of Mg and the entire process from binding to membrane through activation of the enzyme and finally Ca2+ -uptake is dependent on Ca2+ alone. This situation is unique to the placental plasma membranes. It is tempting to speculate that the link between the maternal and the fetal circulation is achieved by forming vesicles loaded with Ca2+ on the maternal side and unloading them through fusion with the basal plasma membrane on the fetal side. The Ca2+ -related properties of placental plasma membranes described in this thesis, provide many answers regarding the first step in the asymmetrical transplacental Ca2+ -transport. Further investigation is required before a full understanding of the entire process is achieved. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

The excitation-contraction-relaxation cycle of the guinea pig ileum longitudinal smooth muscle was studied in muscles contracted by a muscarinic agent, cis-2-methyl-4-dimethylaminomethyl-1,3-dioxolane methiodide (CD) and by 60 mM KC1. Aspects of the cycle were investigated by analyzing the active transport enzyme activities in the sarcolemma, the tissue Ca depots which could release Ca for contraction and the sensitivity of the contractile responses to extracellular ion changes. Essentially net changes of intracellular Ca, Mg, Na and K content during contractions were measured by a modified 'La method'. The tissues were washed for 30 min in 160 mM Tris-HCl solution (pH 7.4) containing 10 mM LaCl₃ at 4°C in order to seal the intracellular ions in the cell and displace extracellular ions. A method to loosen the 'intercellular cementing' substance by reducing the tissue Ca and Mg was developed as an adjunct to the preparation of a sarcolemmal enriched microsomal fraction. The method reduced the tenacity of the tissue and made the tissue easy to disrupt by a mild homogenizing procedure. The method also appeared to aid the extraction of contractile proteins. The microsomal fraction was not detectably contaminated by mitochondria and was enriched with vesicles of sarcolemma, probably originating from the muscle caveolae. The sarcolemma enriched microsomal fraction had a Ca-ATPase activity that was progressively stimulated by 10⁻⁷ to 2.4 x 10⁻⁴ M free Ca²⁺ , did not require Mg and was inhibited by La. The microsomal Ca-ATPase activity was not due to contamination by actomyosin. The actomyosin Ca-r-ATPase in the soluble fraction had a higher affinity than the microsomal Ca-ATPase for Ca and for La. The microsomal Ca-ATPase activity was postulated to be associated with an active Ca pump thought to he located in the cayeolae. The microsomal fraction had a Mg-dependent ATPase that could Be stimulated by Na, but K and ouabain had very little additional effect. The addition of an activating factor in the soluble fraction conferred some K and ouabain sensitivity to the Mg-dependent Na-ATPase, which indicated that a Na,K-ATPase was present in this tissue. Low doses of ouabain contracted the longitudinal ileum but the responses were not antagonized by raising the external K concentration five fold, as would be expected if ouabain acted by inhibiting the Na,K-ATPase. However, the ouabain response was rapidly lost when extracellular Ca was removed from the medium and the decline of the response followed the same time course as the loss of extracellular Ca. The peak of the ouabain contraction coincided with significant increases of intracellular Ca and Na, but K loss was not apparent until relaxation ensued. The results suggested that ouabain has an early direct effect on membrane permeability before it inhibited the Na,K-ATPase. CD (2 x 10⁻⁷ M) and 60 mM KCl induced phasic and tonic contractions of the longitudinal muscle of the ileum. The phasic contraction declined from 100% to 7% over 10 min when Ca was omitted from the physiological medium. This decline followed the time course of the loss of extracellular Ca. This, together with the fact that low concentrations of LaCl₃ inhibited the phasic component, indicated that Ca bound to the outer aspect of the cell was responsible for the phasic component. The tonic component was lost more rapidly than the phasic component when the Ca was removed from the Tyrode's solution. The tonic component seemed activated by free Ca mobilized from the extracellular space. The extracellular origin of the Ca for contraction was consistent with the observed small net gain of intracellular Ca that occurred during the phasic and tonic contractions. The minimal volume of the sarcoplasmic reticulum and the abundance of caveolae was also consistent with the high sensitivity of the tissue to extracellular Ca concentrations. The intracellular Ca gained during contraction wa,s extruded within 30 sec after the CD or 60 mM KCl were washed out of the tissue bath, Following washout of CD, the muscle was quiescent for the 20 to 30 min 'equilibration' phase. Spontaneous activity was absent during this phase and tension was below baseline. After a maximal CD contraction, a second response to CD or to 60 mM KCl induced during the 'equilibration' phase had an altered or desensitized biphasic appearance. Responses of the muscle to CD for 10 min were accompanied by a cytoplasmic loss of K. After washout of CD, the K was regained slowly over 20 to 30 min. Stimulation of the tissue by 60 mM KCl did not cause a loss of K from the muscle nor did it cause desensitization of the muscle. Higher extracellular K concentrations decreased the time required after CD contractions for the return of spontaneous activity and prevented muscle desensitization to repeated doses of CD, probably by accelerating the return of intracellular K levels to normal. It was proposed that during contraction, elevated intracellular Ca activated K channels, thereby increasing K permeability and causing the 'after-hyperpolarization' and subsequent desensitization which follows muscarinic induced contractions. / Pharmaceutical Sciences, Faculty of / Graduate

This thesis is a study of the effect of lipid injections on complement titers of guinea pigs.

O Brasil ocupa uma posição de destaque mundial em relação à produção agropecuária, sendo necessário fornecer segurança microbiológica aos consumidores. Salmonella é um agente causador de infecções alimentares em seres humanos, de forma que os produtos de origem suína são responsáveis por cerca de 5-10% dos surtos em humanos. O controle depende do conhecimento da distribuição da bactéria desde o rebanho até o frigorífico. Em regiões com altas prevalências no campo, esforços direcionados primeiramente em reduzir a prevalência nos rebanhos visam minimizar os riscos de contaminação dos produtos. Neste sentido, medidas de biossegurança, seguindo boas práticas de produção agropecuária, são fundamentais. Além disso, a aplicação de intervenções complementares são, possivelmente, formas de reduzir a prevalência em um período de tempo mais curto. Desta forma o objetivo deste trabalho foi validar três estratégias: 1) utilização de um prebiótico Actigen®™ na ração dos animais, (PRE); 2) uma vacina viva Enterisol SC 54®, (VAC) e 3) o sistema de wean-to-finish, (WTF). Estes grupos foram comparados entre si e com o sistema tradicional em três sítios, o grupo controle (GC), frente à soroprevalência e contaminação em carcaças. Cada estratégia foi realizada em três repetições, sendo colhidas amostras de sangue de 55 animais de cada lote no dia do alojamento na terminação e quatro dias antes do abate. Suabe de 40 carcaças de cada lote foram colhidas antes do resfriamento. As soroprevalências e frequências de isolamento foram comparadas entre os grupos por meio de teste de qui-quadrado. A soroprevalência pré-abate foi estatisticamente menor no grupo PRE 50,3% em relação ao WTF, VAC e GC, com 99%, 96,9% e 98,8% respectivamente. As frequências de isolamentos em superfície de carcaça variaram de 0% a 29,1% nos grupos PRE e VAC respectivamente, sendo que ambas diferem significativamente entre si e dos grupos CG 18,33% e WTF 15% (p<0,05). Pode-se comprovar a eficácia do prebiótico em prevenir a infecção a campo frente às demais estratégias. Em relação às contaminações de carcaças, os resultados corroboram com os conhecimentos acerca do papel da pressão de infecção do campo nas contaminações na planta frigorífica. / Brazil has been increasing its worldwide position in relation to agricultural production, and is necessary providing food safety to consumers. Salmonella is a foodborne pathogen for humans and pork products play an important role in the amount of outbreaks. The control depends on the knowledge of the distribution of the bacteria occurrence from the herd to the slaughterhouse. In regions with high on farm prevalence, efforts are primarily directed to reduce the prevalence in the swine population in order to minimize the risks of products contamination. In this sense, biosecurity measures and good production practices are useful. Moreover, increase the knowledge about additional interventions, to reduce on farms prevalence in a shorter period of time, also is important. Therefore, the objective of this work was to validate three strategies: 1) use of Actigen ® ™ prebiotic in animal feed, (PRE); 2) a live vaccine Enterisol SC54® (VAC); and 3) the system of wean- to-finish, (WTF). Seroprevalence and contamination on carcasses surface in these groups were compared with the traditional system in three sites (the control group-CG). Each strategy was performed in three replicates, and blood samples were collected from 55 animals of each batch at the first day of finishing phase and four days before slaughter. Swabs of 40 carcasses were taken from each batch before chilling. The seroprevalence and isolation frequencies were compared between groups using logistic regression. The seroprevalence before slaughter was lower in PRE (50.3%) compared with the WTF, VAC and GC groups, with 99%, 96.9% and 98.79%, respectively. The frequency of Salmonella isolation was lower in PRE group 0%, when compared with the other groups (p<0.05). The results prove that prebiotic is able to prevent infection in the field compared to the other strategies. Regarding the carcass contamination, these finds are consistent with the knowledge on the role of infection pressure in the field contamination in the plant.

Cystic fibrosis (CF) is a common lethal hereditary disease resulting from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR dysfunction affects multiple organ systems and most morbidity and mortality in CF results from lung disease. The CF lung appears healthy at birth, but spontaneously develops airway disease characterized by infection, inflammation, mucus plugging and airway remodeling. A CF pig model was recently generated to determine the events that initiate lung disease. CF pigs recapitulate many findings seen in humans with CF, including the spontaneous development of lung disease. I used newborn CF pigs to investigate two leading hypotheses regarding CF disease initiation: abnormal airway surface liquid (ASL) composition and defective mucociliary transport (MCT). I developed an assay to study ASL composition and found that CF ASL contained similar sodium concentrations, elevated potassium concentrations, and a decreased fraction of volatile material. I developed an assay to measure MCT in vivo. By tracking individual particles in 3-dimensions I found that newborn pigs exhibit a ventrally directed cilia orientation in the trachea. I also found that MCT is highly heterogeneous and particles traveled at different speeds within airways and between airways, challenging the classic view that airway mucus exists as continuous blanket. Comparing particle transport revealed that non-CF and CF newborn pigs exhibit similar basal particle clearance and speeds. Cholinergic stimulation induces mucus and fluid secretion. Particles became stuck in newborn CF pigs after cholinergic stimulation and stasis persisted with tissue submersion. This challenged the leading hypothesis that attributes CF airway disease pathogenesis to ASL depletion. I hypothesized that adherent mucus impairs mucociliary transport in CF airways and I developed an assay to visualize mucus stasis in submerged tracheal segments ex vivo. CF trachea stimulated in vivo exhibited highly adhesive mucus entities that emerged exclusively from submucosal gland ducts. These adherent entities impaired MCT even with extremely high ASL depths. Non-CF trachea with combinatorial disruption of HCO3- and Cl- transport reproduced the defect in CF signifying that anion transport disruption was responsible for adherent mucus. These data suggest that CFTR disruption directly produces multiple host defense defects, including defective bacterial killing and abnormally adherent mucus. Therapeutic targeting of the described defects may provide new opportunities to intervene early and improve the lives of those with CF.

No description available.

While much is known about the attachment of the chlamydiae to the host cell and intracellular events during the developmental cycle, little is known about the mechanism(s) by which elementary bodies exit the cell. In this report, we use the guinea-pig conjunctival model of Chlamydia caviae infection to present in vivo ultrastructural evidence supporting two mechanisms for release of chlamydiae from the mucosal epithelia. Four days after infection, histopathologic observation shows an intense infiltration of polymorphonuclear leukocytes (PMN) in the conjunctival epithelium. Using transmission electron microscopy, a gradient-directed PMN response to chlamydiae-infected epithelial cells was observed. As PMN infiltration intensifies, epithelial hemidesmosome/integrin/focal adhesion adherence with the basal lamina is disconnected and PMNs literally lift off and release infected superficial epithelia from the mucosa. Many of these infected cells appear to be healthy with intact microvilli, nuclei, and mitochondria. While lysis of some infected cells occurs with release of chlamydiae into the extracellular surface milieu, the majority of infected cells are pushed off the epithelium. We propose that PMNs play an active role in detaching infected cells from the epithelium and that these infected cells eventually die releasing organisms but, in the process, move to new tissue sites via fluid dynamics.

Few studies in the area of psychodietetics have concentrated upon the relationship between a single dietary nutrient and behavior. However, some vitamins have been shown to be particularly important to central nervous system activity. Among these is Vitamin C (ascorbic acid). Two experiments were done to determine the effects of ascorbic acid deficient diets on a learning task in which guinea pigs were subjects. Learning was defined as acquisition and extinction of shock-escape and shock-avoidance behavior. In Experiment I, twelve adult guinea pigs were fed diets containing two different deficient amounts of ascorbic acid for six weeks. They were then run on shock-escape, shock-avoidance and extinction schedules. No significant differences in behavior among the dietary groups were shown by statistical analysis, either in acquisition or extinction. In Experiment II, three adult guinea pigs were fed the same ascorbic acid-deficient diets as in Experiment I for six weeks after a baseline performance on a shuttlebox shock avoidance schedule was obtained. Performance after dietary treatment among or across subjects was not observably different from the performance prior to treatment. Serum and adrenal protein analysis confirmed that the dietary treatment had lowered the total ascorbic acid content of the serum and adrenals, but behavior did not show a corresponding or consistent change. These results indicate that ascorbic acid deficient diets fed to adult guinea pigs did not result in a change in behavior as observed on shock-escape, shock-avoidance, or extinction schedules.