Thesis (PhD (Plant Production and Soil Science)--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (Ph. D.)--Victoria University (Melbourne, Vic.), 2007. / Includes bibliographical references.

Thesis (Ph. D.)--Victoria University (Melbourne, Vic.), 2007. / Includes bibliographical references.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2009. / Includes bibliographical references. Also available on the World Wide Web.

Research suggests that specific compositions of gut microbiota can directly affect energy harvesting and fat storage, which may indicate a potential role of intestinal bacteria in the regulation of body weight (i.e., obesity). The purpose of the current study was to determine if prebiotic- and probiotic-based diets modify gut microbiota in genetically obese rodents. For this, female Zucker diabetic fatty (ZDF) rats were assigned diets containing fructooligosaccharides (FOS), Bifidobacterium (BIF), or Lactobacillus (LAC) for three weeks. qPCR was then used to measure levels of colonic Bifidobacterium, Lactobacillus, and total bacteria. At termination, there was no significant difference in Lactobacillus levels between diets. However, there was significantly less Bifidobacterium in BIF vs. FOS or LAC-fed rats. The evidence in this study shows there were no significant differences in Lactobacillus levels between any of the feeding groups and the control group, supporting the conclusion that ingestion of any of the tested supplemented feed does not statistically modulate Lactobacillus numbers in female ZDF rats. However, the rats from the Bifidobacterium and FOS feeding groups had significantly higher colonic Bifidobacterium levels than the control group from ingesting the supplemented feed, indicating that the presence of the probiotic Bifidobacterium animalis subspecies lactis and the prebiotic FOS stimulated the growth of Bifidobacterium.

Extreme physical exertion is commonly associated with acute physiological changes in immune variables known to disturb host defences. Likely induced by the production of stress hormones (e.g., cortisol), partaking in ultra-endurance events with accompanying physiological stressors (e.g., environmental extremes, sleep deprivation and compromised hydration and (or) nutritional status) may amplify stress hormone responses and compromise immune status to a greater extent. To date, research investigating the impact of extreme physical exertion (e.g., ultra-marathon events) on physiological variables is extremely limited. More recently, the potential use of probiotics with known immunomodulatory effects may be considered an appropriate nutritional strategy to improve host defences and minimise and (or) prevent sub-clinical or clinically significant outcomes in active populations.

Acne vulgaris is a chronic inflammatory skin disorder, which affects the pilosebaceous units of the skin. Although this disease is normally self-limiting, it affects over 50 million Americans and results in lost productivity and treatment costs exceeding 1.2 billion dollars annually.1 While the exact cause of acne is unknown, its pathogenesis is classified into four factors: increased sebum production, abnormal keratinization, hypercolonization by Propionibacterium acnes, and inflammation.2 Despite numerous treatment options, increasing resistance to antibiotics3 and significant side effect profiles of many other therapeutics has created a need for safer, gentler treatment options. There has been renewed interest in the gut-skin-brain axis theory and the therapeutic role of oral probiotics, as new evidence suggests that gut dysbiosis plays an important role in mediating cutaneous skin inflammation and acne lesions.2 Specifically, strains of Lactobacillus acidophilus and Bifidobacterium bifidum, two strains commonly found in probiotics, have been found to decrease gut permeability and reduce systemic inflammation associated with acne.4 Additionally, in small clinical trials, these strains decreased acne severity and had an supplemental effect on clinical efficacy when used with oral antibiotics.5 Despite these promising results, the lack of large randomized controlled trials with standardized outcome measurements has prevented the adoption of oral probiotics as a viable treatment option by domestic and international dermatological societies. Therefore, this study proposes a randomized control trial to determine whether the adjunctive use of oral probiotics with antibiotics significantly reduces acne severity compared to oral antibiotics alone. We hypothesize that there will be a statistically significant decrease in acne severity scores among those receiving oral probiotics and antibiotics compared to those receiving only antibiotics among adolescents between the ages of 12-24 with moderate to severe acne. We hope that these study results will help provide evidence to incorporate oral probiotics into practice as a safe and efficacious treatment option to those suffering from moderate to severe acne, while advancing our understanding of how mediating gut microbiota can improve acne outcomes.

Salmonellosis is one of the most important foodborne zoonotic diseases throughout the world and poultry represents an important source of infection in humans. Chickens may become infected during incubation, in the brooding houses, through various vectors, such as feed and rodents or during slaughtering and processing. The use of antibiotics have been reduced and even banned in some countries, due to the risk of bacterial populations developing resistance against the antibiotics. This lead to the exploration of alternative products for antibiotics as growth promoters, which include prebiotics, probiotics, organic acids, essential oils, plant extracts and many more. These products may improve animal health, productivity and microbial food safety in a natural way. A feeding trial was conducted to investigate the effects of the dietary inclusion of probiotics and a prebiotic to improve the health and performance of broilers, which were challenged with Salmonella typhimurium. 1800 chicks (900 chicks exposed to Salmonella and 900 chicks not exposed) were randomly assigned to 6 dietary treatments for 5 weeks. The dietary treatments were: 1) No feed additives added, 2) A prebiotic (fructooligosaccharide) added to the feed, 3) Probiotic type 1 (Spore-forming bacteria) added to the feed, 4) Probiotic type 1 combined with the prebiotic added to the feed, 5) Probiotic type 2 (Lactobacillus spp.) added to the feed, 6) Probiotic type 2 combined with the prebiotic added to the feed. The feed intake, average daily gain and body weight of the control (nonchallenged) birds were significantly higher (P<0.05) than the Salmonella (challenged) birds. The Probiotic type 2 combined with the prebiotic improved the feed intake of the non-challenged birds compared to the non-challenged birds that received no supplementation or only a prebiotic. The challenged and non-challenged birds that did not receive any supplementation had lower body weights and average daily gains compared to the birds that received supplementation. The feed conversion ratio showed significant differences among the treatments (P<0.003) and between the control and Salmonella birds (P<0.05). The non-challenged birds fed the Probiotic type 2 combined with a prebiotic and the challenged birds fed only the prebiotic, displayed a decrease in liver weight, compared to the other treatments. However, the duodenum, jejunum and caeca weights of the broilers were significantly (P<0.05) enlarged shortly after Salmonella exposure through the inclusion of Probiotic type 1 and the two combination treatments in the diet. No significant differences were observed in the ileal weights after Salmonella exposure or after dietary supplementation. The total serum protein and the aspartate amino transferase (AST) levels showed no significant differences between the groups and treatments. However, the albumin levels of the challenged birds were significantly lower (P<0.05) than the non-challenged birds. The globulin levels were higher for the challenged birds that did not receive any supplementation than those that received a prebiotic and probiotics. The albumin: globulin ratios were higher for the non-challenged birds than the challenged birds. In general, the challenged birds tended to have more lesions than the non-challenged birds on the gastrointestinal tract (GIT). There were no significant differences in the villous height, mucosal thickness and crypt depth of the duodenum, jejunum and ileum. However, the control birds supplemented with Probiotic type 2 combined with a prebiotic showed a thicker mucosa layer than the control that received no supplementation. These findings indicate that the supplementation of a basal diet with probiotics and combination treatments of probiotics with a prebiotic can be used as growth promoters for broilers. These products, especially the Probiotic type 2 combined with the prebiotic, show promising effects as alternatives for antibiotics as pressure increases to eliminate the growth promotant antibiotics from being used in the livestock industry. / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted

Over the past decade the poultry industry has made tremendous improvements in production and efficiency that can be attributed to areas of nutrition. Feed additives are one area of nutrition that the poultry industry utilizes to improve performance and efficiency. Experiment 1 investigated the effects of two nutrient densities diets and three enzyme inclusion strategies on 59 d Ross x Ross 708 male broiler performance under a natural disease challenge. These data suggest that when supplementing EIS2 broiler performance and processing characteristics are improved. Additionally, HD also improved broiler performance. The objective of the second experiment was to examine the interactive effects of probiotic and copper inclusion on 42 d Ross x Ross 708 male broiler performance. The resulting data suggests that inclusion of Cu-H at 250 ppm enhances broiler performance while lowering E.coli presence. These data also suggests that BL and Cu-H interact, ultimately reducing the efficacy of BL.