Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Haiqiang Chen, Animal & Food Sciences. Includes bibliographical references.

Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Aug. 8, 2007. Includes bibliographical references.

Thesis (MSc)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Starch-containing agricultural crops are widely available as feedstocks for the production of fuel ethanol, potable spirits or beer, single-cell protein (animal feed) and high-fructose corn syrups (sweeteners). Starch-rich crops, such as maize, rye, barley and wheat, are usually used for the production of whisky. One of the first steps in the production of whisky is to boil the raw starch at temperatures exceeding 100°C. This gelatinisation step is performed to disrupt and solubilise the starch granules to make them more accessible for enzymatic hydrolysis. After this cooking process, the starch is liquefied by a-amylase and then saccharified by glucoamylase and a debranching enzyme. Lipomyces kononenkoae and Saccharomycopsis fibuligera secrete highly effective a-amylases and glucoamylases, making them two of the most efficient raw-starchdegrading yeasts known. However, L. kononenkoae and S. fibuligera cannot be used in existing industrial fermentations because of their low ethanol tolerance, slow growth rate, catabolite repression, poorly characterised genetics and lack of GRAS (Generally Regarded As Safe) status. This study is divided into two sections. The aim of the first section was to clone a gene (LKA2) encoding a novel starch-degrading enzyme, a second a-amylase (Lka2p) from L. kononenkoae. LKA2 was cloned into a multicopy plasmid, the yeast episomal plasmid, YEp352, under the control of the phosphoglycerate kinase promoter (PGK1 p) and terminator (PGKh) expression cassette. This recombinant plasmid was designated pJUL3 and transformed into a laboratory strain of S. cerevisiae, I1278b. Plate and liquid assays revealed that the recombinant yeast secreted active a-amylase into the medium. The optimum pH for Lka2p was pH 3.5 and the optimum temperature 60°C. The aim of the second part of the study was to construct recombinant strains of S. cerevisiae secreting a-amylase and/or glucoamylase. The individual genes were cloned into a yeast-integrating plasmid, Ylp5, under the control of the PGK1p-PGK1.,-expression cassette. Two indigenous yeasts were selected on the basis of their ability to utilise raw starch, L. kononenkoae and S. fibuligera, as gene donors. Eight constructs containing the L. kononenkoae a-amylase genes, LKA 1 and LKA2, and the S. fibuligera a-amylase (SFA 1) and glucoamylase (SFG1) genes were prepared: four single-cassette plasmids expressing the individual coding sequences under the control of the PGK1 p-PGK1.,- expression cassette, resulting in plPLKA 1, pIPLKA2, plPSFA 1 and pIPSFG1, respectively; two double-cassette plasm ids (expressing both LKA 1 and LKA2 under the control of the PGK1p-PGK1 .,-expression cassette, and SFA 1 and SFG1 under their respective native promoters and terminators), resulting in pIPLKA1/2 and pIPSFAG, respectively, and two single-cassette plasmids expressing SFA 1 and SFG1 with their native promoters and terminators, resulting in pSFA 1 and pSFG1, respectively. The respective constructs were transformed into a laboratory strain of S. cere visiae , L1278b. By homologous recombination, each plasmid was integrated into the yeast genome at the ura3 locus. S. cerevisiae L:1278b that had been transformed with plPLKA 1/2, LKA 1 and LKA2 under the control of the PGK1 rrPGK1,expression cassette resulted in the highest levels of a-amylase activity when assayed for amylolytic activity in a liquid medium. This recombinant strain resulted in the most efficient starch utilisation in batch fermentations, consuming 80% of starch and producing 6 gIL of ethanol after 156 hours of fermentation. The strain expressing SFG1 under the control of the PGK1rrPGK1,expression cassette gave the highest levels of glucoamylase activity.' These results confirmed that co-expression of a-amylase and/or glucoamylase synergistically enhance starch degradation. This study paves the way for the development of efficient starch-degrading strains of S. cerevisiae for the production of whisky, beer and biofuel ethanol. / AFRIKAANSE OPSOMMING: Styselbevattende landbougewasse kom wydverspreid voor as die substraat vir die produksie van brandstofetanol, drinkbare spiritualië of bier, enkelselproteïen en hoëfruktose graanstroop. Styselbevattende gewasse, soos mielies, rog, gars en koring, word gewoonlik vir die produksie van whisky gebruik. Die eerste stap in die produksie van whisky is om die stysel by temperature bo 1DOOG te kook. Hierdie jelatinisasie stap word uitgevoer om die styselkorrels te versteur en vloeibaar te maak sodat hulle meer toeganklik vir ensimatiese hidrolise is. Na dié kookproses word die stysel deur o-arnilases vervloei en dan deur glukoamilases en 'n vertakkingsensiem versuiker. Lipomyces kononenkoae en Saccharomycopsis filuligera skei hoogs effektiewe a-amilases en glukoamilases uit, wat dit twee van die effektiefste rou-stysel-afbrekende giste bekend, maak. L. kononenkoae en S. fibuligera kan egter nie in reeds bestaande industriële fermentasies gebruik word nie, as gevolg van hulle lae etanoltoleransie, stadige groeitempo, katabolietonderdrukking, swak gekarakteriseerde genetika en gebrek aan ABAV (Algemeen Beskou As Veilig) status. Hierdie tesis is in twee afdelings verdeel. Die doel van die eerste deel was om 'n geen (LKA2) wat vir 'n nuwe, unieke styselafbrekende ensiem kodeer, te kloneer, 'n tweede a-amilase (Lka2p) van L. kononenkoae. LKA2 is in 'n multikopie plasmied, die gis episomale plasmied, YEp352, onder beheer van die fosfogliseraatkinasepromotor- en termineerder-kasset (PGK1 p-PGK1 r), gekloneer. Hierdie rekornbinante plasmied is pJUL3 genoem en in 'n laboratoriumras van Saccharomyces cerevisiae, L:1278b, getransformeer. Plaat- en vloeibare-ensiem toetse het getoon dat die rekombinante gis aktiewe a-amilase in die medium uitskei. Die optimum pH vir Lka2p is 3.5, is en die optimum temperatuur 60oG. Die doel van die tweede deel van die studie was om rekombinante rasse van S. cerevisiae te konstrueer wat a-amilases en/of glukoamilases uitskei. Die individuele gene is toe in 'n gis-integreringsplasmied, Ylp5, onder beheer van die PGK1p-PGK1,ekspressiekasset, gekloneer. Twee inheemse giste is op grond van hulle vermoë om stysel te benut geselekteer, L. kononenkoae en S. filuIigera, as geen donors. Agt konstrukte bevattende die L. kononenkoae se a-amilasegene, LKA 1 en LKA2, en S. filuligera se a-amilasegeen (SFA 1) en glukoamilasegeen (SFG1), moes gekonstrueer word: vier _enkel-kasset plasmiede wat die individuele koderende sekwense onder beheer van die PGK1 p-PGK1, ekspressiekasset uitdruk, wat onderskeidelik plPLKA 1, pIPLKA2, plPSFA 1 en plPSFG1 lewer; twee dubbel-kasset plasmiede (wat beide LKA 1 en LKA2 onder beheer van die PGK1 p-PGK1,ekspressiekasset, en SFA 1 en SFG1 met hulle onderskeie inheemse promotors en termineerders) uitdruk, wat onderskeidelik pIPLKA1/2 en plPSFAG lewer, en twee enkel-kasset plasmiede wat SFA 1 and SFG1 met hulonderskeie inheemse promotors en termineerders, en wat onderskeidelik pSFA 1 en pSFG1 lewer. Die onderskeie konstrukte is in 'n laboratoriumras van S. cerevisiae, L1278b, getransformeer. Deur middel van homoloë rekombinasie, is die onderskeie plasmiede in die ura3-lokus van die gisgenoom geïntegreer. S. cerevisiae L1278b, getransformeer met plPLKA 1/2, LKA 1 en LKA2 onder die beheer van die PGK1 ~PGK1 ïekspressiekasset, het die hoogste vlakke van a-amilase aktiwiteit gelewer toe dit vir amilolitiese aktiwiteit in vloeibare medium getoets is. Hierdie rekombinante ras het stysel die effektiefste benut, nl. 80% van die stysel en 'n opbrengs van 6 gIL etanol na 156 ure in lotfermentasies. Die ras wat SFG1 onder beheer van die PGK1~PGK1ïekspressiekasset uitdruk, het die hoogste vlakke van glukoamilase-aktiwiteit gelewer. Hierdie resultate bevestig dat die gesamentlike uitdrukking van a-amilase- en/of glukoamilase-ensieme styselafbreking sinergisties . bevorder. Hierdie studie baan die weg vir die ontwikkeling van 'n effektiewe styselfermenterende ras van S. cerevisiae wat moontlik gebruik kan word vir die produksie van whisky en biobrandstofalkohol.

Made available in DSpace on 2014-10-09T12:51:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:05Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The objective of this work, achieved in the framework of the BIOCOR European Network, has been to provide the operators of Sea-Water Injection System (SWIS) with improved decision support. The implication of biological component on carbon steel corrosion was explored as well as the possible synergy with other elements (mechanical stress, material properties…). This work showed that biogenic sulphide production, a corrosion threat for steel, can have different origins in seawater. The production rate can determine kinetics and morphology of corrosion attack, which might be governed by the type of microorganisms present. The key parameters are the availability of electron acceptors and the surrounding environment temperature. Sulfate-Reducing Bacteria (SRB) exhibit more vigorous attack compared to sulfidogenic bacteria or genera Clostridium, both found in the studied SWIS. Microbial activity also affects the mineralization process naturally occurring on carbon steel surface leading to architectures composed of mixed iron (II) and (III) minerals such as iron sulfides, magnetite, iron oxyhydroxides, chukanovite and green rust (sulfated or carbonated) as well as calcareous deposits. Inner layers of these structures could possibly provide an anaerobic habitat for SRBs, where they can flourish by using sulfate from GR(SO42-) as a terminal electron acceptor for their dissimilatory respiration. This enables continuous degradation of steel. Finally, significance of material microstructure and impact of mechanical stress on corrosion processes was also recognized. Grain boundaries and inclusions are playing a role during the initial stage of corrosion attack. This impact can diminish during the immersion time. An elevated bacterial activity coupled with mechanical stress leads to an increase of material deterioration. However, the mechanisms are not different from those usually observed for unstressed steel. Moreover, sulfidogenic microbial activity does not seem to lead to a failure mechanism related to Stress Corrosion Cracking (SCC). In conclusion, the outcomes indicate the possible situations, which may (or may not) lead to breach the safe operating window for a given SWIS.

Os métodos de tratamento para a obesidade em cães e gatos focam na restrição calórica, seja restringindo a ingestão de alimento ou alimentando o animal com dietas hipocalóricas. Entretanto, esses métodos frequentemente falham, sendo necessárias estratégias alternativas para promover a perda de peso. O objetivo desse estudo foi investigar as diferenças na microbiota fecal entre animais magros e obesos e determinar se a castração e/ou a perda de peso estão associadas com mudanças na população microbiana. No primeiro experimento, a composição da microbiota fecal foi avaliada nos gatos magros inteiros, magros castrados e obesos castrados, antes e depois da perda de peso. Os gatos obesos foram submetidos a seis semanas de restrição energética e apresentaram redução na massa gorda após a perda de peso (P<0,001), embora o peso corporal não tenha mudado (P>0,05). Firmicutes, seguido de Bacteroidetes foram os filos predominantes em todos os grupos. O grupo dos magros castrados tiveram o perfil de bactérias que era esperado para os obesos, com maior abundância de Firmicutes e menor de Bacteroidetes (P<0,05). Não foram observadas diferenças entre os grupos magros inteiros e obesos castrados. A população microbiana dos gatos obesos mostrou poucas alterações com a perda de peso. No segundo experimento, o teste foi realizado quando os cães estavam magros, após consumo ad libitum para promover o ganho de peso e após a perda de peso. As seguintes concentrações séricas foram analisadas: glicose, colesterol, triglicerídeos, albumina, creatinina, fosfatase alcalina (FA), alanina aminotransferase (ALT), proteínas totais (PT), insulina e leptina. As amostras de fezes foram analisadas para determinar a abundância de Bacteroidetes e Firmicutes. As concentrações de triglicerídeos, colesterol, albumina, FA, ALT e PT foram maiores (P<0,05) nos cães obesos quando comparados aos magros. Bacteroidetes foi mais abundante (P<0,001) nos magros e Firmicutes não diferiu entre os grupos (P>0,05). Após a perda de peso, os níveis de colesterol e PT e a abundância de Bacteroidetes permaneceram inalteradas estatisticamente. Conclui-se então que, nos modelos testados, há diferenças na microbiota fecal entre os grupos dos estudos realizados. Entretanto, no estudo com os gatos a obesidade pareceu não influenciar o crescimento das diferentes populações de microorganismos. / Treatment methods for obesity in dogs and cats focus on calorie restriction, either by restricting the calorie intake of the animal, or by feeding energy diluted diets. However, these methods often fail, requiring additional strategies to promote weight loss. The objective of this study was to investigate differences in the gut microbiota between lean and obese animals and determine whether neutering and/or weight loss are associated with changes in the microbial populations. In the first experiment, the composition of the faecal microbiota was evaluated in lean intact, lean neutered and obese neutered cats, before and after weight loss. The obese cats were submitted to six weeks of energy restriction and showed less fat body mass after weight loss (p<0.001), although the body weight has not changed (P>0.05). Firmicutes followed by Bacteroidetes were the predominant bacterial phyla in all groups. The lean neutered cats had a bacterial profile of what one would expect from the obese cats, with greater abundance (P<0.05) of Firmicutes and lower abundance (P<0.05) of Bacteroidetes. There were no significant differences between lean intact and obese neutered. The microbe populations of obese cats showed very few changes with weight loss. In the second experiment, testing was performed when the dogs were lean, after ad libitum feeding to promote weight gain and after weight loss. Serum concentrations were analyzed: glucose, cholesterol, triglycerides, albumin, creatinine, alkaline phosphatase (ALP), alanine aminotransferase (ALT), total proteins (TP), insulin and leptin. Faecal samples were analyzed to determine the abundances of Bacteroidetes and Firmicutes. Triglycerides, cholesterol, albumin, PA, ALT and TP were greater (P<0.05) in obese dogs when compared to the lean. The abundance of Bacteroidetes was greater (P<0.001) in the lean group and the phylum Firmicutes showed no differences among the groups (P>0.05). After weight loss, the levels of cholesterol and TP and the abundance of Bacteroidetes remained unchanged statistically. In conclusion, differences in the faecal microbiota were observed among the groups of both studies. However, in the study with cats, obesity seems not to influence the growth of diverse populations of microrganisms.

In order to develop novel antibacterial therapies that combine anti-adhesion, anti-quorum sensing and the delivery of conventional antibiotics, the effects of polymers on bacterial aggregation and quorum sensing (QS) were studied. QS is a term used to describe method by which bacteria use chemical signal molecules to modulate pre-infection behaviour such as surface attachment. Polymers that can interfere with bacterial adhesion or the signal molecules used for QS are therefore a potential means to control bacterial population responses. In this thesis, the ability of the cationic polymers poly (N-[3-(dimethylamino) propyl] methacrylamide) (p(DMAPMAm), P1) and poly (N-dopamine methacrylamide-co-N-[3-(dimethylamino) propyl] methacrylamide) (p(DMAm-co-DMAPMAm), P2) to cluster a range of bacteria, such as Staphylococcus aureus(Gram-positive), Vibrio harveyi, Escherichia coli and Pseudomonas aeruginosa(Gram-negative) under conditions of varying pH and polymer concentration was investigated. It was identified that clustering ability was strongly dependent on the balance between charge and hydrophobicity. The results also suggested that catechol moieties might have a positive effect on adhesive properties. Moreover, the potency of polymers against QS of Vibrio harveyi was assayed via testing bioluminescence. P1 which was able to bind to the surface of bacteria through electrostatic interactions enhanced the expression of QS and P2 which could bind to both the bacteria and QS signals showed the ability to both enhance and reduce light production. Furthermore, polymeric vesicles made of copolymers containing poly (3,4-dihydroxy-L-phenylalanine methacrylamide) (p(L-DMAm)) which displayed similar dual affinity compared toP2 were prepared and their ability to modulate QS responses in Vibrio harveyi was demonstrated. All the vesicles showed higher potency in quenching bioluminescence than their linear polymer analogues. To explore the feasibility of using self-assembled polymers for anti-microbial drug delivery, silver loaded DOPG lipid vesicles were made and were found to interfere with QSwhile reducing bacterial viability when the concentration of Ag+ was above the MIC (0.1 μg/mL). The results overall suggested that combined antimicrobial therapies might be possible using polymers and both QS and cytostatic or cytotoxic agents.

Bacteria communicate with each other by releasing chemicals called quorum sensing molecules. A common gram-negative bacteria, Pseudomonas aeruginosa, releases a number of such molecules including, N-3-(oxododecanoyl)-L-homoserine lactone (3OC12-HSL) and Pseudomonas quinolone signal (2-heptyl-3,4-dihydroxyquinoline, PQS). The quorum sensing molecules have immunomodulatory effects on mammalian cells in addition to their role in bacteria. There has been very little study of the vascular effects of quorum sensing molecules on the host. The aim of this thesis was; therefore, to investigate the effect of Pseudomonas aeruginosa quorum sensing molecules, 3OC12-HSL and PQS, on vascular function and endothelial cell permeability and to study the potential mechanisms involved. Both 3OC12-HSL and PQS caused slowly developing vasorelaxation in arterial and venous preparations isolated from pigs. PQS was slightly more potent (pIC50) as a vasorelaxant than 3OC12-HSL. The endothelium was not a prerequisite for 3OC12-HSL-induced vasorelaxation since removal of endothelium and the nitric oxide synthase inhibitor (L-NAME) did not attenuate responses. Indeed, the opposite is true since 3OC12-HSL vasorelaxation responses were larger in the absence of the endothelium and nitric oxide. The mechanism of 3OC12-HSL does not involve either prostanoids, cyclic GMP, mitochondrial targets, calcium channels, chloride channels, PPAR-γ receptors, pannexin receptors, gap junctions or cystic fibrosis transmembrane conductance regulator. However, ouabain and depolarisation induced by potassium chloride decreased 3OC12-HSL responses suggest an impact on membrane potential. Overnight exposure of the porcine coronary artery to wild type Pseudomonas aeruginosa (PAO-L), produced a selective reduction in the magnitude of contractions to potassium chloride. However, neither 3OC12-HSL nor PQS produced an inflammatory response with prolonged exposure since they did not modify tumor necrosis factor alpha or vascular tone under these conditions. Both 3OC12-HSL and PQS increased endothelial cell permeability. Both caused a fall in endothelial resistance and an increase in FITC-dextran transport across human brain microvascular endothelial cells (HBMECs). The immunoblotting data showed that the levels of adherens junction and tight junction protein expression were decreased in HBMECs exposed to 3OC12-HSL, but not PQS. Rather PQS, but not 3OC12-HSL, caused a concentration-dependent phosphorylation of p38 MAPK, suggesting these molecules may modify vascular permeability by different mechanisms. In summary, these data show that 3OC12-HSL and PQS affect mammalian vascular function by decreasing vascular tone and increasing endothelial permeability. The potential advantage of these effects of quorum sensing molecules on host cells allowing bacteria to promote increase local circulation or produce oedema or allow access to promote systemic infection.

The human gut microbiota is considered to be a highly specialized organ providing nourishment, regulating epithelial cell development, modulating innate immune responses and colonization resistances, and it significantly impacts human health and disease. Dispite of being extensively studied for several decades, the functionality of the microbiota colonization in the human gastrointestinal tract and the mechanisms of the interactions between the host and bacteria are still poorly understood. This research follows a novel and unique approach, which combines the complementary strengths of in vitro experiment, in vivo study and mathematical modelling. The work undertaken has three emphases: 1) probiotic strains and their impact on human health; 2) the development of gut microbiota in infants; 3) quantification of human gut microbial ecosystem at both the species level and the system level. In the first part of this research, a versatile anaerobic continuous culture platform was implemented following a novel and unique design, which allows easy and continuous sampling and monitoring of microbial growth. A number of carefully planned in vitro experiments have been conducted to investigate the growth and competition of probiotic strains under different culture conditions. These in vitro experiments improve the understanding for the growth behaviour of the specific probiotic strains. The second part of this project analyzed 50 faecal samples collected from 9 healthy infants with administration of probiotic strains and placebo. The analysis is based on the 454-pyrosequencing technology, which reveals the complete profiles of gut microbiota in these infants and confirmed the modulation effect of the specific probiotic strains. The last part of this research focused on the development of mathematical and computational models of human gut microbial ecosystem. The outcome from this part of the research includes: a) a new bacterial growth model that overcomes the parodox of competitative exclusion caused by previous models; b) a versatile computational framework to simulate in vitro fermentation experiments; and c) a comprehensive mathematical model for human gut and gut microbiota that is the first model for its nature.

Orientador: Paulo Francisco Domingues / Banca: Simone Baldini Lucheis / Banca: Erika Cosendey Toledo de Mello Peixoto / Resumo: O objetivo deste trabalho foi avaliar a influência de dois tipos de sistemas de produção sobre a produção de leite e a ocorrência de mastite em ovelhas da raça Bergamácia. Também foram analisados no leite os níveis de proteína, gordura, sólidos totais e lactose. Determinou-se no sangue e no leite os níveis dos seguintes minerais: cálcio (Ca), zinco (Zn), sódio (Na), potássio (K) e fósforo (P), e as vitaminas A e E. Foram utilizadas 35 ovelhas distribuídas em dois grupos: Grupo 1 (G1;n=16) em sistema de pasto rotacionado (Panicum maximum cv. Tanzânia) e o Grupo 2 (G2;n=19) em confinamento com dieta balanceada, contendo silagem de milho e concentrado. Os dois grupos foram avaliados por um período de 8 semanas. Nos dois sistemas de produção os cordeiros foram separados das mães 48 horas após o nascimento. Para o diagnóstico da mastite clínica utilizou-se diariamente o teste da caneca telada, e semanalmente, o California Mastitis Test (CMT) e a contagem de células somáticas (CCS) para a mastite subclínica. Observaram-se os seguintes valores médios para os minerais, analisados a cada 15 dias em amostras de leite e plasma, nos grupos G1 e G2, respectivamente: Ca (1,55g/L e 0,24g/L; 1,57g/L e 0,23g/L); Zn (0,025g/L e 0,003g/L; 0,027g/L e 0,003g/L); Na (0,75g/L e 3,44g/L; 0,73g/L e 3,34g/L); K (1,43g/L e 0,24g/L; 1,48g/L e 0,91g/L) e P (4,49g/L e 0,027g/L; 4,59g/L e 0,025g/L). Os valores médios para vitamina A no leite e sangue, respectivamente: G1 (1,025μmol/L e 2,445μmol/L) e G2 (0,915μmol/L e 2,518μmol/L). Os valores médios para vitamina E no leite e sangue, respectivamente: G1 (17,513μmol/L e 35,568μmol/L) e G2 (17,982μmol/L e 35,318μmol/L). Conclui-se que os animais confinados apresentaram produção de leite maior quando comparado com os animais a pasto, entretanto, estatisticamente não significativo. A ocorrência de mastite subclínica infecciosa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the influence of two types of systems on dairy production and the occurrence of mastitis in Bergamacia ewes. The levels of protein, fat, total solids and lactose were also assessed in milk. The following minerals had their levels quantified in blood and milk: calcium (Ca), zinc (Zn), sodium (Na), potassium (K) and phosphorus (P), as well as the vitamins A and E. Thirty-five ewes were distributed into two groups: Group 1 (G1; n=16) in rotational grazing system (Panicum maximum cv. Tanzânia) and Group 2 (G2; n=19) in confinement, with a balanced diet containing corn silage and concentrate. Both groups were evaluated for 8 weeks, so that lambs were separated from their mothers 48h after birth. To diagnose clinical mastitis, strip cup test was daily performed. In addition, California Mastitis Test (CMT) and somatic cell count (SCC) were weekly assessed to evaluate subclinical mastitis. The following mean values were detected for minerals, which were analyzed every 15 days in milk and plasma samples from G1 and G2, respectively: Ca (1.55g/L and 0.24g/L; 1.57g/L and 0.23g/L); Zn (0.025g/L and 0.003g/L; 0.027g/L and 0.003g/L); Na (0.75g/L and 3.44g/L; 0.73g/L and 3.34g/L); K (1.43g/L and 0.24g/L; 1.48g/L and 0.91g/L) and P (4.49g/L and 0.027g/L; 4.59g/L and 0.025g/L). The mean values for vitamin A in milk and blood were, respectively: G1 (1.025μmol/L and 2.445μmol/L) and G2 (0.915μmol/L and 2.518μmol/L). For vitamin E, the mean values in milk and blood were, respectively: G1 (17.513μmol/L and 35.568μmol/L) and G2 (17.982μmol/L and 35.318μmol/L). We concluded that confined animals had higher dairy production, compared to those in grazing system, although there was no statistical difference. Infectious subclinical mastitis was 25.0% for grazing animals and 31.5% for confined ones. The agents isolated from the latter were Streptococcus spp. (83.3%)... (Complete abstract click electronic access below) / Mestre