The main aim of the studies was to evaluate the modes of actions of Bio-Mos and the effect that it has on intestinal health as well as performance in broiler chickens. For the purpose of this study there were 2 main objectives. The first was to determine the effect of Bio-Mos as well as soluble mannan on salmonella colonization and to do this it was necessary to develop an in vivo pathogen challenge model, specifically designed for salmonella, using the chicken as animal model. The aim with this salmonella assay was to design a model that could accurately determine the efficacy of different components of the yeast cell wall at reducing or eliminating salmonella colonisation in chickens. The second objective was to evaluate the effect of Bio-Mos with or without the addition of a soluble mannan, fed at different inclusion levels, on chicken health. Specific parameters measured included feed conversion ratios (FCR), volatile fatty acid (VFA) analysis, antibiotic resistance amongst coliform populations, immunoglobulin quantification and gut morphology. Gut morphology measurements included villi height and width, crypt depth, muscularis thickness, goblet cell size and goblet cell density. The salmonella assay trial was not able to yield positive results for either the cell wall preparations or the positive control, indicating that there are some external factors that have to be addressed before this assay can be used to draw any accurate conclusions from. The second section of this study did show FCR differences between some of the treatments, but did not show numerically large differences for VFA production or antibiotic resistance, however the histological evaluation did yield interesting results. Measurements based on the villi height and width, crypt depth and muscularis thickness showed no significant differences between treatments but there was a treatment effect on the goblet cells. The goblet cells of chickens receiving cell wall preparations were statistically significantly larger and present at a higher density than those of the control treatment birds. In an attempt to develop the salmonella assay several aspects of the existing assay model were altered or eliminated. It is possible that the assay can work with some more adjustments, but due to time constrictions it was not possible to further explore alternative approaches. Little research has been done on the effect of nutrition on the goblet cells in chicken intestines. The results noted in this report warrant a more in-depth investigation into the exact modes of action resulting in the differences in goblet cells observed. The use of cell wall preparations on a commercial level holds many advantages, as cell wall preparations appear to affect animal health in a positive way. / Dissertation (MSc (Agric) : Animal Nutrition)--University of Pretoria, 2008. / Animal and Wildlife Sciences / MSc (Agric) / unrestricted

Despite their beneficial effects, concerns have been raised about the role of antimicrobial growth promoters (AGP) in the emergence of antibiotic resistant bacteria. This study evaluated the effects of approved AGP on the emergence of antibiotic resistance in commensal E. coli and foodborne pathogen Salmonella. A survey of antibiotic resistance levels in commercial broiler chicken farms in the Fraser Valley (B.C.) and an experimental feeding trial were conducted from May 2004 to February 2005 and May to November 2005, respectively. The latter examined the effects of ten AGP formulations (bambermycin, penicillin, salinomycin, bacitracin, combination of salinomycin and bacitracin, chlortetracycline, virginiamycin 11ppm, virginiamycin 22ppm, monensin and narasin) on bird performance as well. Multiple antibiotic resistant commensal E. coli and Salmonella carrying virulence genes were found at commercial broiler chicken farms and therefore may serve as reservoirs for these genes. There was no significant difference between feed formulations on the phenotypic or genotypic characteristics of the isolates, except for tetracycline resistance gene tet(B). In the experimental feeding trial, broiler chickens were fed a diet including or excluding AGP. Birds were sampled prior to and weekly during feeding of the control and the AGPP containing diets. Although not detected on day 0, E. coli increased after day 7 to more than 9.9 log10 CFU/g in ceca. Multi-drug resistant E. coli were isolated from birds fed the ten AGP containing diets as well as the control diet. Except for penicillin, none of the AGP containing diets significantly improved bird performance compared to the control diet (P>0.05). Good management practices can significantly improve broiler chickens performance and decrease the mortality rate. / Land and Food Systems, Faculty of / Graduate

Orientadores: Irenilza de Alencar Naas, Marta dos Santos Baracho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-14T11:27:11Z (GMT). No. of bitstreams: 1 Menezes_AdrianaGomesde_M.pdf: 3659236 bytes, checksum: 9ed106bcdf2c0254a5318139cf5e3141 (MD5) Previous issue date: 2009 / Resumo: O presente trabalho propôs um estudo exploratório para determinar os pontos críticos de controle, gargalos e possíveis riscos do incubatório e da granja de produção de frango de corte. A pesquisa foi conduzida em um incubatório e em dois aviários na região do interior do Estado de São Paulo. O experimento foi conduzido nas seguintes salas do incubatório: sala de ovos, câmera fria, pré-aquecimento, incubadora e nascedouro. Os seguintes dados foram coletados no incubatório e nos aviários: dados de temperatura (T,?C) e umidade (UR,%), velocidade do ar (VA, m s-1), temperatura superficial do ovo e do pintinho (tS,?C), níveis de amônia (NH3) e luminosidade. Na avaliação dos aviários foi aplicado o questionário do manual de Boas Práticas de Produção de Frango de Corte, bem como entrevistas com os colaboradores/produtores e posterior aplicação da matriz de análise de risco para determinar os pontos críticos de controle. Após a coleta dos dados foi aplicado o Controle Estatístico do Processo (CEP), através da análise de Índice de Capacidade do Processo utilizando o software Minitab15®. Os pontos críticos identificados no incubatório e nas duas granjas analisadas foram a temperatura ambiente e umidade relativa. As categorias que se configuraram como pontos críticos de controle foram: cama de aviário, alimentação, água, higiene e saúde do trabalhador, manejo e biosseguridade, normas e legislações, instalações e planejamento das atividades. Pôde-se concluir que a análise dos PCCs associada às ferramentas de controle CEP, às diretrizes de boas práticas de produção e às demais literaturas consultadas, contribuíram para a garantia da segurança alimentar da produção avícola industrial, resultando em maior confiança na cadeia de produção. / Abstract: This research presents an exploratory study to determine the critical control points, bottlenecks and possible risks of the incubation process and farm production of broilers. The research was conducted in an incubatory and two aviaries in the state of São Paulo. The experiment was conducted in the following rooms of the incubatory: egg room, cold camera, pre-heating and hatchery. The following data were collected in the incubatory and in the aviaries: temperature (T?C), humidity (% RH), air velocity (AV m s-1), surface temperature of the egg and the chick (ST), ammonia levels and light intensity. In the assessment of the aviaries, the following tools were applied: the questionnaire from the Manual of Good Practices for Broiler Production, interviews with employees/producers and subsequent application of the matrix of risk analysis to determine the critical control points. After collection of data, the Statistical Process Control (SPC) was applied, through the analysis of the Process Capability Index PCI and PC, using the software Minitab15®. The critical points identified in the incubatory and in the two farms were T(ºC) and RH(%). The topics that were taken into consideration as critical control points were: poultry litter, food, water, hygiene and health of workers, husbandry and biosecurity, legislation, facilities and planning of activities. It was observed that the analysis of PCCs associated with statistical control tools, guidelines of good practices for production as well as information from existing literature, contributed to ensuring the food safety of the poultry production industry, resulting in higher levels of trust in the production chain. / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

MSCAGR (Animal Science) / One of the ways to minimise cost and promote health in humans and animals is to use natural feed additives instead of antibiotics. Moringa oleifera (Moringa) is a phytobiotic which possess anti-microbial and immune-modulatory properties and contains high levels of nutrients and it can be used as a feed additive. Probiotics are feed additives which consist of living microorganisms that have beneficial effects on the physiology and health of other organisms. The objective of the study was to determine the effect of various levels of Moringa oleifera and probiotics inclusion on growth performance, carcass characteristics and cost benefit analysis for broiler chicken production. Moringa oleifera leaf powder was purchased from Bethel Farm No:683 Bethel mission Gucksdadt Vryheid in Zululand district AbaQulusi municipality. The study was a 5x2 factorial design with five levels of Moringa and two levels of probiotic. Six hundred (600) Ross 308-day old chicks were received and fed commercial starter. The experimental treatments were randomly divided into five levels of Moringa with and without probiotics introduced through drinking water at grower to finisher phase. The diets were supplemented with different inclusion levels of Moringa (Mo) as follows: 0g/kg (M0), 0.6g/kg (M3), 1.2g/kg (M6), 1.8g/kg (M9), 2.4g/kg (M12) of Moringa oleifera leaf meal (MOLM) and probiotic at P0 (0ml/bird/week), P1 (1 ml/bird/week) of a commercial probiotic administered in water for the first three weeks (starter phase). The experiment had three replications with 20 birds per replicate. MOLM and PRB interaction had no significant effect (P>0.05) on any of growth parameters and same findings with MOLM. Probiotics treatments had significantly reduced (P < 0.05) mortality rate (MTRT) in the grower phase. MOLM×PRB had significant effect on (P<0.01) feed intake (FI), MOLM had significantly reduced (P< 0.05) average bodyweight gain (ABWG) and FI in finisher phase. MOLM and PRB interaction had significant effect (P< 0.05) on dressed weight only and non-significant effect (P>0.05) on the rest of carcass parameters. MOLM inclusion levels did not significantly affect (P>0.05) back fat weight. However, MOLM inclusion level significantly reduced (P< 0.05) dressed weight, shank length, wing weight, drum and thigh weight, back weight and breast muscle weight. PRB inclusion in the diets significantly increased (P< 0.01) shank size and drum + thigh weights (P<0.05). MOLM and PRB inclusion level had no significant effect (P>0.05) on giblets parameters. MOLM and PRB interaction had significant effect on (P<0.05) water holding capacity (WHC) and hardness. MOLM had significant effect (P<0.05) on pH and dripping loss. A significant effect between (MOLM×PRB) Moringa oleifera leaf meal and probiotics (P<0.01) was observed on CD, C* and b*. MOLM had significant effect (P<0.01) on CD, C*, a*, b*, L*, PRB had significant effect (P<0.01) on h*(increased) and a*(reduced) on colour parameters. MOLM fed at P0 resulted in higher mortality at grower stage. It is concluded that MOLM can be added up to 12% with or without PRB without affecting growth performance at finisher phase and carcass characteristics. Inclusion of MOLM up to 12% had good impact on hardness and water holding capacity in the meat. PRB presence improved the growth performance of birds supplemented with MOLM up to 12% inclusion level. MOLM diets were not economically profitable compared to control diet due to high price level of Moringa oleifera powder supplemented in the diets and no best return weight gain per rand invested amongst the diets. / NRF

Emerging broiler famers are faced with the challenge of acquiring contracts with the contract providers in South Africa. The question is, are these emerging farmers able to perform well financially regardless of the availability of contracts to their disposal. Profitability is one of the core issues to the development and sustainability of emerging broiler farmers. A well performing farmer is the one who is able to manage and improve the good financial performance of the farm in general. In order to determine the financial performance of the farm, financial ratios can be useful in determining and analyzing how a farm performs financially. In this study, four financial ratios are used to analyze and determine how emerging broiler farmers in Gauteng perform financially. This is done through a representative farm model which makes use of ten emerging farmers situated in the southern and northern sides of Gauteng. Out of ten emerging broiler farmers that took part in the study, the results show that only two of them are producing under contracts. This is an indication that emerging broiler farmers in Gauteng are characterized by both financial and production risk. This further implies that farmers who do not have contracts are likely to have a poor financial performance in as far as broiler enterprise is concerned. The study establishes the differences between the contract growers and the non contractors that form the representative farm model and this is achieved by looking the results of the financial ratios. The study further distinguishes the financial performances between the southern and northern sides of Gauteng which form the representative farm model. The results indicated that although 80% of the emerging broiler growers in Gauteng do not produce under contracts, they are still able to perform well financially. However the contract growers outperform the no contractors in terms of financial performance due to a well defined market structure. / Dissertation (MScAgric)--University of Pretoria, 2010. / Agricultural Economics, Extension and Rural Development / unrestricted

The South African broiler industry is the greatest contributor to the South African agricultural sector, while at the same time providing the cheapest form of protein to the South African consumer. In light of a recent application for increased tariffs due to the industry’s inability to compete with the price of imported products, the need for a tool that is able to quantify the benefit of increased tariff protection to producers, while at the same time considering the cost of increased tariffs on South African consumers became apparent. The integrated nature of the industry however raised the concern that the assumptions associated with traditional quantitative modelling techniques, particularly that of a perfectly competitive market, would not allow the current broiler model within the BFAP sector modelling framework to represent the industry accurately. The primary objective of the study was to determine the true method of price discovery within the South African broiler market, in order to specify a price equation that is able to capture the dynamics surrounding price formation with improved accuracy. This price formation mechanism was then integrated into a simulation model that represents the industry accurately. Due to its ability to represent reality within the market with greater accuracy, the New Institutional Economic (NIE) framework was used to analyse the structure of the South African broiler industry as action domain. The actors and activities in the value chain were evaluated, followed by an analysis of the institutions that govern exchange within the market, highlighting the implications of these institutions for price formation within this coordinated market structure. Upon evaluation of compensation structures used within broiler production contracts, it became evident that the market for live broilers produced by contract growers could be considered as a market for grower services, as opposed to a market for live broilers. Compensation based on a broiler production tournament offers significant incentives for greater efficiency, effectively ensuring that production efficiency increases on a continuous basis. Despite the contractual obligation of integrated producers to pay their contracted growers based on a formula including the cost of production, the broiler producer price is negotiated between integrators and retailer, within a concentrated market structure. The cost of production is used as bargaining tool in price negotiations, yet the availability of imported products at extremely competitive prices limits the extent to which increased production costs can be passed up through the value chain. This was confirmed by the fact that the response of the domestic broiler producer price was much more elastic to changes in the international price than to changes in feed costs. The theoretical factors that drive broiler producer prices in South Africa were confirmed econometrically through the use of an error correction model, estimated empirically using secondary monthly data from 2007 to 2012. The estimated equations were integrated into a partial equilibrium framework using an import identity to establish equilibrium in the market, rather than a price equilibrator. The inelastic response from the domestic broiler producer price to changes in broiler feed prices raised questions regarding South African producers’ ability to compete with imported products and produce sustainably in the long run. Given the higher costs of production domestically, as well as the relative size and importance of the broiler industry within the South African agricultural sector, the need to evaluate the tariff application objectively was clear. Policy decisions should weigh the benefit of increased producer prices on broiler producers against the cost of protective policy to consumers, while also considering the specific consumers that would be required to bear the cost of increased tariffs. Integration of the partial equilibrium model of the broiler industry into the BFAP sector modelling framework enabled the simulation of various tariff scenarios, quantifying the effect on the agricultural sector, as well as chicken consumption. At the same time, the successful simulation of different scenarios and policy shocks validated the model. Simulation of the tariffs applied for by SAPA resulted in a producer price increase of 6%, which would be a significant margin on the bottom line for domestic producers. The cost to consumers of a 3.3% increase in retail prices also seems digestible; however the underlying factors that drive competitiveness should also be addressed in order to ensure long run sustainability for the industry. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

Respiratory disease complex is a major cause of mortality and economic losses in the commercial broiler industry. In 1991 a previously unidentified bacterium associated with respiratory disease and cranial cellulitis was isolated from broilers in the then Transvaal Province (van Beek, van Empel, van den Bosch, Storm, Bongers, du Preez, 1994. ). In 1994 the organism was named Ornithobacterium rhinotracheale (Vandamme, Segers, Vancanneyt, van Hove, Mutters, Hommez, Dewhirst, Paster, Kersters, Falsen, Devriese, Bisgaard, Hinz, Mannheim, 1994.). Since then Ornithobacterium rhinotracheale has been isolated worldwide from chickens and turkeys showing respiratory signs and has become well established as contributing to the respiratory disease complex in both species (van Empel, Hafez, 1999). In South Africa respiratory disease and Ornithobacterium rhinotracheale in particular is routinely controlled by the inclusion of antibiotics such as Oxtetracycline into the feed of broilers during rearing. Concerns about antibiotic residues in poultry meat for human consumption as well as evidence that suggests that Ornithobacterium rhinotracheale readily develops resistance to antibiotics (Devriese, Hommez, Vandamme, Kersters, Haesebrouck, 1995), make this strategy unsustainable. It was with a view to reducing producers’ dependence on long term prophylactic antibiotic therapy that this study to determine the safety and efficacy of an OR bacterin vaccine was carried out. Injection of the bacterin into broilers was deemed impractical on a commercial scale, so it was applied to broiler breeder parent stock in order that they could protect their progeny through vertically transmitted immunity developed as a result of vaccination. Breeder flocks were vaccinated intramuscularly at nine and 18 weeks with a monovalent bacterin based on OR serotype A with oil adjuvant. Vaccine safety was evaluated by palpation of vaccination sites and clinical observation of breeders for two weeks after vaccination. The serological response of breeders to vaccination was monitored using an ELISA test for Ornithobacterium rhinotracheale optimised for use under South African conditions. Vaccine efficacy was determined by monitoring of broiler progeny of vaccinated breeders raised under commercial conditions as well as through controlled challenge studies with Ornithobacterium rhinotracheale under laboratory conditions. In order to determine the financial consequences of using the test vaccine, a partial farm budget was drawn up from available broiler data and possible outcomes were modelled using a stochastic model. The vaccine proved to be safe for use in commercial broiler breeders and vaccinated birds developed a good humoral response to vaccination. As a result of cross-contamination of isolators with Ornithobacterium rhinotracheale the results of the challenge studies were inconclusive. No evidence of protection of broiler progeny of vaccinated breeder flocks could be detected through the challenge trials. In the absence of in-feed medication, broilers hatched from vaccinated breeders did, however, performed better under commercial conditions than those hatched from unvaccinated breeder flocks. The partial farm budget showed that broilers raised from OR vaccinated breeder flocks were more profitable than the negative control flocks. The quantitative risk analysis showed that the probability of making a relative profit from broilers as a result of OR vaccination of parent stock was 74%, from the use of in-feed medication in broilers from unvaccinated parents was 70% and from a combination of the interventions was 99%. It can be concluded that the last of these options was most profitable. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2003. / Veterinary Tropical Diseases / unrestricted

<p>  </p> <p>This thesis aimed to evaluate the effect of heat treatment of different ingredients on their respective phosphorus digestibility and assess the impact of protein source in the basal diet on the regression-derived phosphorus digestibility methodology. Two studies were carried out to evaluate the objectives.</p> <p>In study 1, regression-derived ileal digestibility and utilization coefficients of phosphorus (P) responses to autoclaving soybean meal (SBM) or poultry meal (PM) were investigated in two experiments. On day 19 post hatching male Cobb 500 broiler chickens were individually weighed and allotted into 6 or 5 treatments in experiment (Exp.) 1 or 2, respectively, in a randomized complete block design, with 8 replicate cages and 8 birds per cage in both experiments. In Exp. 1, diets were formulated with either non-autoclaved or autoclaved soybean meal at 380, 480, or 580 g/kg in a 2 file:///C:/Users/vshae/AppData/Local/Temp/msohtmlclip1/01/clip_image002.png 3 factorial arrangement. Experiment 2 consisted of a basal diet and other four diets, with 40 or 80 g/kg of non-autoclaved PM or autoclaved PM arranged as a 2 file:///C:/Users/vshae/AppData/Local/Temp/msohtmlclip1/01/clip_image002.png 2 + 1 factorial. Chromic oxide was added as an indigestible index marker to determine nutrient ileal digestibility and retention. Birds received the experimental diets for 3 days, and excreta collection was conducted during the last two days. All birds were euthanized by CO2 asphyxiation, and ileal digesta samples were collected. Data were analyzed using the GLM procedure. In both studies autoclaving decreased (<em>P</em> < 0.05) DM digestibility and retention. Increasing the inclusion level of test ingredients linearly increased (<em>P</em> < 0.05) intake of digestible and utilizable P in both studies and linearly reduced the digestibility and retention of DM and P in the soybean meal study. Autoclaving SBM resulted in higher (<em>P</em> < 0.01) ileal digestibility of P and retention of P and Ca. The estimated ileal digestibility of P in SBM, autoclaved SBM, PM, and autoclaved PM were 45, 53.6, 61.2 and 61.2%, respectively, and the corresponding retention were 40.6, 45, 51.7, and 59.2%. Autoclaved SBM tended (<em>P</em> = 0.058) to have higher P digestibility than non-autoclaved, but no effect was noted with PM. These results indicated that autoclaving feed ingredients reduced the digestibility and retention of dry matter, and the digestibility of phosphorus of soybean meal may be improved by heat treatment but not that of poultry meal, which may be due to phytate P degradation.</p> <p>The second study was conducted to evaluate the effect of varying protein sources in the basal diet on the regression-derived P digestibility in soybean meal. This experiment was organized in a 4 × 3 factorial arrangement, consisting of 4 diet types that differed in their protein sources; with the test ingredient as the only source of protein, or with one of 3 protein supplements (casein, potato protein isolate (PPI) or dried egg albumen (DEA)) added at 60 g/kg, and 3 levels of test ingredient (SBM) inclusion at 290, 370 or 450 g/kg. Male Cobb 500 broiler chickens were individually weighed and distributed in the 12 treatments in a randomized complete block design, with 8 replicate cages and 6 birds per cage on day 19 post hatching. Birds were fed the experimental diets for 3 days, and ileal digesta and excreta samples were collected similarly to the first study. Diet type affected (<em>P</em> < 0.01) the digestibility and total tract retention of DM, P, N, and Ca. Diets with added casein presented the highest (<em>P</em> < 0.05) digestibility of P, Ca, and N, retention of P and Ca, and intake of digestible and utilizable P. The digestibility and retention of DM linearly decreased (<em>P</em> < 0.001) with increasing inclusion levels of SBM in all diet types. The estimated ileal digestibility of P in SBM was 56.9, 62.6, 59.1, and 36.4% for diets without protein supplements, with casein, PPI, or DEA, respectively; the corresponding retention of P were 51.7, 82.6, 42.7, and 52.2%. Diet type affected (<em>P</em> < 0.05) the slope and intercept of P digestibility in SBM. A comparison of the coefficients using confidence intervals demonstrated that the ileal digestibility of P in SBM determined in diets with DEA was lower (<em>P</em> < 0.05) than in the other diet types, which were not different from one another. These results indicate that the selection of dietary protein supplements may affect P digestibility essays using the regression method. </p> <p>In summary, the digestibility of P in soybean meal may be improved by heat treatment while not that of poultry meal, which may be ascribed to the higher phytate P content of SBM, and phytate degradation from heat treatment. Results from the second study demonstrated that the protein source, but not level in the basal diet affects the P digestibility of the essay ingredient determined using the regression method. These findings can contribute to reducing P excretion by enhancing the formulation of broiler diets on a digestible P basis, providing information on the effect of heat treatment on dietary P availability, and refining the methodology used to determine P digestibility.</p>

This experiment was conducted to determine the differences in meat quality (cooking loss and shear force), descriptive sensory characteristics, consumer acceptance, and whole muscle proteomes between normal and Pale, Soft, and Exudative (PSE) broiler breast meat. Male Hubbard × Cobb 500 birds (n = 1,050) were raised in commercial houses. Prior to harvest, a sample of the broilers (n = 900) were subjected to short-term stress (38 °C for 2 h), and the remaining broilers (n = 150) were maintained at control conditions (21 °C for 2 h). From the stressed and control condition broilers, breast samples were characterized by pH24 and L*24 as normal (pH24 5.8-6.2, L*24 45-55) or PSE (pH24 5.4-5.7, L*24 55-65). Normal chicken breast meat had lower shear force values than PSE meat (P < 0.05). Based on sensory descriptive analysis, normal cooked chicken breast was more tender and juicier than PSE breast meat (P < 0.05). Consumer sensory analysis results indicated that 81% of consumer panelists liked normal breast meat whereas 62% of the panelists liked PSE breast meat. Whole muscle proteome profiling identified fifteen differentially abundant proteins (P < 0.05) in normal and PSE meat samples. Actin alpha, myosin heavy chain, phosphoglycerate kinase, creatine kinase M type, beta-enolase, carbonic anhydrase 2, proteasome subunit alpha, pyruvate kinase, and malate dehydrogenase were over-abundant in PSE meat whereas phosphoglycerate mutase-1, alpha-enolase, ATP-dependent 6-phosphofructokinase, and fructose 1, 6-bisphosphatase were over-abundant in normal meat. In addition, normal and PSE broiler breast meat were sampled from commercial plants and evaluated for meat quality attributes (pH, color, cooking loss, and tenderness) and their whole muscle proteome. Normal chicken breast meat had lower shear force values than PSE meat (P < 0.05). Proteome analysis revealed five differentially abundant proteins (P < 0.05) between the normal and PSE chicken breast samples. Glycolytic enzymes (beta-enolase and fructose-bisphosphate aldolase C) were over-abundant in PSE breast meat. Myofibrillar protein (myosin heavy chain) was over-abundant in PSE breast meat. In conclusion, results indicated that differences in proteome abundance could be related to the meat quality differences between normal and PSE breast meat.

Lactic acid producing bacteria (LAB) and organic acids have been proposed as effective alternatives to antibiotics, however there is limited literature concerning their combination. Thus, the objective of this thesis was to investigate the effects of LAB, encapsulated butyric acid (EBA), and their combination. Under challenged conditions, the in vitro study demonstrated that both EBA and LAB were capable of reducing pathogen proliferation over time, with greater efficacy at lower initial concentration. However, EBA demonstrated a greater effectiveness on pathogen reduction. Under challenged conditions, the results of the in vivo study indicated that birds fed LAB performed comparatively to that of birds fed antibiotics concerning BW and FCR from d 0-45 and both diets enhanced gut physiology, pH and immune parameters. Overall, the results of the thesis indicate the ineffectiveness of combining EBA and LAB, while providing valuable evidence supporting LAB as an effective alternative to antibiotics.