The goal of this research was to evaluate the effects of calf starter fermentation on rumen pH, metabolic adaptation of ruminal epithelia and growth of calves during the weaning transition. In study 1, calf starter consumption increased short chain fatty acid concentration in the rumen and changed expression of genes involved in ketogenesis and intracellular pH regulation but did not affect rumen pH. In study 2, decreasing dietary starch content did not increase rumen pH. However, feeding a calf starter that had the highest in situ dry matter disappearance lowered rumen pH without adversely affecting feed intake and growth of calves. These findings suggest that rumen epithelium can metabolically adapt to increased fermentation in the rumen at molecular level, and that sub-acute rumen acidosis may not adversely affect feed intake and productivity of dairy calves during the weaning transition. / Animal Science

Abstract High-sucrose diet and metabolic acidosis have some similar effects on bone and they both reduce the formation of dentine. This series of experiments was conducted in order to get information about the effects of acidosis and alkalosis on dentine during primary dentinogenesis and also to ascertain if high-sucrose diet affects dentine formation via acidosis. Chronic metabolic acidosis (0.25 mol/L of NH4Cl in drinking water), chronic metabolic alkalosis (0.25 mol/L of NaHCO3 in drinking water) and chronic respiratory alkalosis (atmospheric pressure equivalent to an altitude of 3000 m) were induced in the rats immediately after weaning for 6 and 7 weeks. One subgroup from each of the main groups was fed a high-sucrose (43%) diet and one a standard maintenance diet, each ad libitum. The control groups had the same diets, but normal drinking water and atmospheric pressure. All the rats were injected with tetracycline (to mark the onset of the experiment in dentine) and inoculated orally with Streptococcus sobrinus. The acid-base status was verified by blood gas analysis at the end of the experiments. After sacrifice, fissure caries was scored with Schiff reagent and the areas of dentinal lesions and tetracycline-marked new dentine were measured from sagittally sectioned mandibular molars. The mineral elements (Ca, Mg, F, Na, P and total mineral contents) of the dentine formed before and during the experiment were measured with an electron probe microanalyzer. With the high-sucrose diet, respiratory alkalosis and metabolic acidosis promoted the initiation and progression of caries while metabolic alkalosis slightly retarded it. With the standard diet, all the experimental conditions slowed the rate of dentine formation and metabolic acidosis had the most pronounced effect. The mineral analysis revealed a totally different pattern of mineralization when the rats with metabolic acidosis (increased calcium and total mineral content) were compared to the previously reported rats with a high-sucrose diet (decreased calcium and total mineral content). Besides this, metabolic alkalosis did not correct the effects of the dietary sucrose on dentine formation and blood gas analysis showed no acid-base disturbances in the sucrose diet group. Therefore, a high amount of sucrose in the diet slows the rate of dentine formation and reduces the ability of teeth to resist caries attack by mechanisms different from those of metabolic acidosis. Nevertheless, metabolic acidosis was found to be the most harmful state of disturbance in acid-base balance for the teeth of young rats, especially with a diet containing a high amount of sucrose.

Based on the initial exploratory results of single-phase (acidogenesis and methanogenesis takes place in one vessel) whey biomethanation studies, a two-phase (acidogenesis and methanogenesis takes place in two separated serial vessels) biomethanation process was found to be more suitable for dealing with the current whey utilisation and/or disposal problem. Acidogenesis was found to be less understood in comparison to methanogenesis and therefore acidogenesis became the central problem of this thesis. Given that 90% of the five-day biochemical oxygen demand in whey is due to lactose, continuous culture (Chemostat) experiments were undertaken to examine the general mechanism of lactose acidogenesis by a mixed undefined culture using ¹⁴C-labeled tracers. Also the influence of whey protein (mainly β-lactoglobulin) on the general fermentation scheme was addressed. Experimental factors included a pH range of 4.0 to 6.5, a mesophilic temperature of 35°C and a dilution rate (D) range of 0.05 to 0.65 h⁻¹. At a fixed pH level, the observed variability in the main acidogenic end products (acetate, propionate, butyrate and lactate) with respect to D were found to be a consequence of the systematic separation of the various microbial groups involved in acidogenesis. Batch incubation of a [¹⁴C(U)]-lactate tracer with chemostat effluent samples and preparative separation of the end products followed by a liquid scintillation assay of the location of the radio activity demonstrated that a microbial population lactate to other end products and hence the observed increase in lactate concentrations at high D values. Further use of [¹⁴C(U)]-butyrate and [¹⁴C(2)]-propionate revealed the predominant carbon flow routes from pyruvate to the various end products. A qualitative lactose acidogenic fermentation model was proposed, in which lactose is converted to pyruvate via the Embden-Meyerhof-Parnas pathway. Pyruvate in a parallel reaction is then converted to lactate and butyrate. In the presence of hydrogen reducing methanogens lactate is converted to acetate in a very fast reaction and not propionate as previously believed-. The implications of these findings with regard to optimising the acidogenic phase reactor are discussed. Acidogenic fermentation of protein together with lactose did not affect the carbon flow scheme. In the D range of 0.05 to 0.15 h⁻¹ low pH (pH < 5.0) was found to favour the butyrate route at the expense of the lactate route and at high pH (pH > 5.5) the lactate route was favoured at the expense of the butyrate route, the pH region of 5.0 to 5.5 being the transition range. In order to describe the microbial growth, the Monod chemostat model was chosen among the various alternatives, because of its simplicity and its physico-chemical basis. The estimated model parameters are reported. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Call number: LD2668 .T4 1978 C38 / Master of Science

Increased cancer risk is associated with select dietary factors. Dietary lifestyles can alter systemic acid-base balance over time. Acidogenic diets, which are typically high in animal protein and salt and low in fruits and vegetables, can lead to a sub-clinical or low-grade state of metabolic acidosis. The relationship between diet and cancer risk prompts questions about the role of acidosis in the initiation and progression of cancer. Cancer is triggered by genetic and epigenetic perturbations in the normal cell, but it has become clear that microenvironmental and systemic factors exert modifying effects on cancer cell development. While there are no studies showing a direct link between diet-induced acidosis and cancer, acid-base disequilibrium has been shown to modulate molecular activity including adrenal glucocorticoid, insulin growth factor (IGF-1), and adipocyte cytokine signaling, dysregulated cellular metabolism, and osteoclast activation, which may serve as intermediary or downstream effectors of carcinogenesis or tumor promotion. In short, diet-induced acidosis may influence molecular activities at the cellular level that promote carcinogenesis or tumor progression. This review defines the relationship between dietary lifestyle and acid-base balance and discusses the potential consequences of diet-induced acidosis and cancer occurrence or progression.

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Memoria para optar al Título Profesional de Médico Veterinario / La asfixia fetal tiene como consecuencia una disminución de la oxigenación, lo que genera un descenso del aporte sanguíneo en los órganos que no son imperativos para la sobrevivencia inmediata, donde comienza a emplearse la glicólisis anaeróbica para producir energía. Esta vía metabólica es menos eficiente, debido a que la energía producida es reducida y las reservas de carbohidratos son rápidamente agotadas, desarrollándose finalmente una acidosis metabólica por la acumulación de acido láctico. Esta ha sido asociada con disminución de la absorción de inmunoglobulinas y falla en la transferencia de inmunidad pasiva. El objetivo de este estudio fue evaluar la relación entre la lactatemia de terneras neonatas, con la concentración de PST y la predisposición a enfermar durante su primer mes de vida. Se realizó entre mayo y agosto de 2014 en una lechería de la zona central e incluyó a 38 terneras Holstein-Friesian. Se tomaron muestras de sangre para medir el lactato sanguíneo con un analizador portátil y estimar las PST por refractometría. Además se registraron los eventos clínicos producidos durante el primer mes de vida. La comparación estadística entre las medias de los parámetros evaluados se realizó con la prueba t de Student. Se relacionó el lactato con las PST por medio de análisis de regresión y se evaluó la habilidad predictiva de la lactatemia en la morbilidad de las terneras con análisis de ROC. Terneras provenientes de distocias tenían mayores concentraciones de lactato sanguíneo (p<0,1) y menores niveles de PST (p<0,05), que terneras nacidas de partos eutócicos. Las terneras que enfermaron presentaron mayores concentraciones de lactato, en comparación con las terneras sanas (p<0,05). No hubo diferencias significativas entre las concentraciones de PST entre sanas y enfermas. Si bien el lactato sanguíneo y las PST evidenciaron una asociación negativa (p<0,1), no hubo una relación estadística entre ambos parámetros baja (r2=0,1). El análisis ROC demostró que la medición de la lactatemia posee cierto valor predictivo de enfermedades, con un punto de corte de 4,5 mmol/l para distinguir entre terneras sanas y aquellas que tienen más probabilidades de enfermar. Por lo tanto, el uso de analizadores portátiles de lactato sanguíneo, constituye una herramienta útil para ser usada en terreno en la detección temprana de terneras con una mayor susceptibilidad de enfermar

Orientador: Mário De Beni Arrigoni / Resumo: O presente estudo teve o objetivo de avaliar o impacto da flutuação natural da ingestão de massa seca no desempenho, características de carcaça, comportamento ingestivo, perfil metabólico sanguíneo e aspectos morfofisiológicos ruminais de bovinos alimentados com dietas de alta inclusão de concentrado, por meio de estudo meta-analítico. Os experimentos contidos na meta-análise utilizaram animais com grupamento genético similar ao utilizado em confinamentos comerciais brasileiros. A meta-análise teve como base de dados os resultados de dez experimentos conduzidos no Confinamento Experimental da Faculdade de Medicina Veterinária e Zootecnia da UNESP, em Botucatu, entre os anos de 2006 e 2015. Os dados foram coletados a partir 838 bovinos, divididos em 238 baias, consideradas as unidades experimentais para o estudo. Os valores de flutuação de ingestão de massa seca na baia foram calculados pela diferença da ingestão de massa seca entre dois dias consecutivos e dividido pelo dia anterior para encontrar o valor em porcentagem. Com base na mediana geral de 5,62%, os animais foram divididos em dois grupos: alta e baixa flutuação de massa seca. As análises estatísticas foram feitas com auxílio do programa computacional R (versão 3.2.3). Utilizou-se um modelo de regressão linear misto para analisar os dados, no qual os experimentos e baias foram considerados como variáveis aleatórias e grupos de flutuação como variável fixa. Os grupos de baixa e alta flutuação apresentaram flutuação mé... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the inpact of natural dry matter intake fluctuation on performance, carcass characteristics, feeding behavior, blood metabolic profile and morphophysiological ruminal aspects of cattle fed with diets of high inclusion of concentrate. The experiments used for this meta-analysis used cattle with genetic group similar to used in Brazilian commercial feedlots. The meta-analysis was conducted using a database of results of ten experiments conducted in Experimental Feedlot of Faculty of Veterinary Medicine and Animal Science, UNESP, Botucatu, between the years 2006 and 2015. Data were collected from 838 bulls, divided into 238 pens, considered the experimental units for the study. The values of dry matter intake fluctuation were calculated by the difference in dry matter intake between consecutive days and divided by the previous day to find the value in percentage. Based on the overall median of 5.62% cattle were classified into two groups: high- or low-fluctuation. All data analysis was performed in R using a mixed model approach where pens and year were random variables and fluctuation group fixed. The low and high fluctuation groups presented a dry matter intake fluctuation average of 4.79% and 6.74%, respectively. Low fluctuation group showed higher dry matter intake as percent of body weight (P <0.01), higher average daily gain (P = 0.05), higher dry matter intake in kg (P = 0.06), greater total weight gain (P = 0.08), as well as greater depositio... (Complete abstract click electronic access below) / Mestre

Two trials were conducted to evaluate effects of feeding barley/canola meal pellets on feedlot performance, subacute ruminal acidosis (SARA), and feeding behaviour in feedlot steers. In trial 1, 350 beef steers (285 ± 22 kg) were backgrounded and finished on pelleted barley and canola meal (PB) or rolled barley and canola meal (RB) diets. Backgrounding DMI was lower (P < 0.05) for PB steers but ADG did not differ (P > 0.05) and feed efficiency (FE) tended (P < 0.1) to be improved. During finishing and the total trial DMI and ADG were lower (P < 0.05) but FE was improved (P < 0.05) for the PB treatment. Steers fed PB were on feed longer (P < 0.05). Steers fed PB showed more variation in DMI (P < 0.05) than steers fed RB. Carcass composition and quality were similar between the treatments.<p>Trial 2 utilized 4 ruminally fistulated beef steers in a 4 x 4 latin square, 2 x 2 factorial trial. Factors were processing (pelleted vs. rolled) and grain type (barley vs. corn). All treatments included canola meal. Each 23 d period consisted of a 19 d adaptation period followed by a 24 h rumen fluid collection period, and a 24 h eating behaviour study. There were no grain type x processing interactions (P > 0.05) or effect of grain type (P > 0.05) on any of the variables. Eating behaviour did not differ (P < 0.05) between treatments. Processing had no effect (P > 0.05) on rumen ammonia or volatile fatty acid (VFA) concentration, proportion of acetate or butyrate, or rumen osmolality. Steers fed pelleted grain had lower (P < 0.05) rumen pH measurements, a greater (P < 0.05) molar proportion of propionate, and decreased (P < 0.05) acetate:propionate ratio. To reflect the feedlot trial corn was removed from the model. Rumen VFA concentration was higher (P < 0.05) and pH lower (P < 0.05) for the PB steers. Results show performance during backgrounding was improved but finishing performance depressed in PB steers. Further research is necessary to reduce the risk of SARA when feeding PB during finishing.

Two trials were conducted to evaluate effects of feeding barley/canola meal pellets on feedlot performance, subacute ruminal acidosis (SARA), and feeding behaviour in feedlot steers. In trial 1, 350 beef steers (285 ± 22 kg) were backgrounded and finished on pelleted barley and canola meal (PB) or rolled barley and canola meal (RB) diets. Backgrounding DMI was lower (P < 0.05) for PB steers but ADG did not differ (P > 0.05) and feed efficiency (FE) tended (P < 0.1) to be improved. During finishing and the total trial DMI and ADG were lower (P < 0.05) but FE was improved (P < 0.05) for the PB treatment. Steers fed PB were on feed longer (P < 0.05). Steers fed PB showed more variation in DMI (P < 0.05) than steers fed RB. Carcass composition and quality were similar between the treatments.<p>Trial 2 utilized 4 ruminally fistulated beef steers in a 4 x 4 latin square, 2 x 2 factorial trial. Factors were processing (pelleted vs. rolled) and grain type (barley vs. corn). All treatments included canola meal. Each 23 d period consisted of a 19 d adaptation period followed by a 24 h rumen fluid collection period, and a 24 h eating behaviour study. There were no grain type x processing interactions (P > 0.05) or effect of grain type (P > 0.05) on any of the variables. Eating behaviour did not differ (P < 0.05) between treatments. Processing had no effect (P > 0.05) on rumen ammonia or volatile fatty acid (VFA) concentration, proportion of acetate or butyrate, or rumen osmolality. Steers fed pelleted grain had lower (P < 0.05) rumen pH measurements, a greater (P < 0.05) molar proportion of propionate, and decreased (P < 0.05) acetate:propionate ratio. To reflect the feedlot trial corn was removed from the model. Rumen VFA concentration was higher (P < 0.05) and pH lower (P < 0.05) for the PB steers. Results show performance during backgrounding was improved but finishing performance depressed in PB steers. Further research is necessary to reduce the risk of SARA when feeding PB during finishing.