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Produção de ácidos graxos voláteis por fermentação acidogênica em reator anaeróbio de leito fixo e extração em resina de troca iônica e com solvente orgânico; Volatile fatty acids production by acidogenic fermentation in an anaerobic immobilized biomass reactor and extraction with ionic change resin and organic solvent

Leite, José Alberto Corrêa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/04/2005 PT
Relevância na Pesquisa
66.34%
Nesse trabalho utilizou-se o reator anaeróbio horizontal de leito fixo (RAHLF) para produção de ácidos graxos voláteis (AGVs). O reator, com volume total de 2,38 litros, foi preenchido com partículas de argila expandida e alimentado com substrato sintético à base de glicose. Com concentração de glicose de 2000 mg/L, sem adição de alcalinizante e com tempo de detenção hidráulica (TDH) de 2 horas, houve produção de ácidos acético, butírico e propiônico. Com a variação do (TDH) de 2 horas para 0,5 hora, em condições idênticas, houve redução da produção do ácido butírico. Na segunda condição testada, em que a concentração da glicose foi 4000 mg/L, a concentração dos três ácidos aumentou, além de ser produzido o ácido capróico. Nas três últimas experimentações, com a glicose a 2000 mg/L e alcalinizada com bicarbonato de sódio, nas concentrações de 0,1000 e 2000 mg/L e TDH em 0,5 hora, as produções do ácido acético e propiônico aumentaram, enquanto que houve diminuição da produção dos ácidos butírico e capróico. A extração dos AGVs foi realizada em coluna de 320 mL de leito, com resina de troca iônica Dowex Marathon A - tipo aniônica base forte de amina quaternária em gel de divinil benzeno-estireno como matriz. O primeiro sistema extratante testado...

Produção de hidrogênio e ácidos orgânicos por fermentação acidogênica em reator anaeróbio de leito fluidificado; Hydrogen and volatile fatty acids production by acidogenic fermentation in anaerobic fluidized bed reactor

Shida, Gessia Momoe
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/04/2008 PT
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96.37%
A matéria orgânica presente nas águas residuárias representa uma matéria prima barata para integrar o processo de digestão anaeróbia e gerar fontes de energia alternativas, como o hidrogênio. O hidrogênio pode substituir os combustíveis fósseis não renováveis e diminuir as emissões de gases do efeito estufa responsável por grande parte da mudança climática global. A combustão do hidrogênio com o oxigênio produz somente vapor d'água e representa 2,75 vezes mais conteúdo de energia que qualquer hidrocarboneto. Além disso, os ácidos orgânicos gerados no processo podem ser utilizados como fonte de carbono para a produção de metano, hidrogênio por organismos fototróficos e biopolímeros e, para a remoção de nutrientes biológicos. A produção de hidrogênio tem sido estudada em reatores de crescimento suspenso e de crescimento imobilizado como o reator anaeróbio de manta de lodo (UASB), reator anaeróbio de leito fixo e reator anaeróbio de leito fluidificado. O objetivo desse estudo foi avaliar a produção de hidrogênio e ácidos orgânicos em um reator anaeróbio de leito fluidificado contendo argila expandida como material suporte. O reator tinha 190 cm de altura, 5 cm de diâmetro interno e um volume de 4192 'CM POT.3'. O reator foi inoculado com lodo pré-tratado termicamente a 90°C por 10 minutos para o enriquecimento do inóculo acidogênico. O sistema foi operado com tempo de detenção hidráulica (TDH) de 8...

Composição química, produção in vitro de gases da fermentação entérica e ácidos graxos de cadeia curta de gramineas forrageiras tropicais; Chemical composition, in vitro rumen gas production, short chain volatile fatty acids of tropical forage grasses

Nguluve, Damião Wetimane
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/12/2014 PT
Relevância na Pesquisa
96.3%
A análise de alimentos para ruminantes consite na caracterização da sua composição química, que varia em função da edafoclimatologia e manejo agrotécnico ao longo do tempo. O manejo de desfolhação (28 e 42 dias), o genótipo e estações constituem fonte de variação da degradabilidade in vitro da matéria seca (DIVMS), acúmulo de gases no rúmen (PG), metano (CH4) e do perfil dos ácidos graxos de cadeia curta (AGCC), com reflexos na eficiência da produção animal. A introdução dessas práticas no cultivo dos gêneros Brachiarias e Cynodon pode disponibilizar forragem de boa qualidade nutricional, com baixos teores de fibra. As dietas baseadas nas gramíneas tropicais são ricas e fibra e trazem controvérsias nos sistemas de produção de ruminantes, pela emissão de dióxido de carbono (CO2) e de CH4 entéricos, com efeito de estufa (GEE) na atmosfera, proposto para reduzir pela comunidade internacional. Contudo, a mitigação dos GEE exige a quantificação da sua produção por área, animal e por ano. Econmicamente, o CH4 enterico é uma perda de 2-12% de energia que poderia ser convertida em produto animal. O objetivo do estudo foi descrever e explicar os efeitos da frequência de desfolhação (28 e 42 dias)...

Control of Salmonella Enteritidis in turkeys using organic acids and competitive exclusion product

Milbradt, E. L.; Zamae, J. R.; Araujo Junior, J. P.; Mazza, P.; Padovani, C. R.; Carvalho, V. R.; Sanfelice, C.; Rodrigues, D. M.; Okamoto, A. S.; Andreatti Filho, R. L.
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 554-563
ENG
Relevância na Pesquisa
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Aim: To evaluate the use of organic acids (OAs) and competitive exclusion (CE) product administered continuously in the feed and transiently in drinking water on the control of Salmonella enterica subspecie enterica serotype Enteritidis (SE) prior to slaughter.Methods and Results: The influence of treatments were evaluated on pH, population of the lactic acid bacteria (LAB) and bacteria of the family Enterobacteriaceae, concentration of volatile fatty acids and SE colonization in the crop and caecum. The birds were challenged with SE 24 h before being slaughtered, and then, the caeca and crop were removed and subjected to SE counts. Continuous administration of OAs reduced the population of bacteria from the Enterobacteriaceae family in both crop and caecum, positively influenced the butyric acid concentration and reduced SE colonization in the caecum. The diet supplemented with CE product positively influenced the quantity of LAB in the crop and caecum, elevated the butyric acid concentration and reduced both Enterobacteriaceae quantity and SE colonization in the caecum. There was no effect from administering the treatments via drinking water on the variables measured.Conclusions: Continuous supplementation in feed with OAs and CE product reduced SE colonization of the caeca.Significance and Impact of the Study: Supplementation of OAs and CE product in diet to turkeys can reduce the SE load...

Effects of age and mannanoligosaccharides supplementation on production of volatile fatty acids in the caecum of rabbits

Guedes, Cristina; Mourão, José Luís; Silva, Severiano; Gomes, Maria José; Rodrigues, M.M.; Pinheiro, Victor
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
96.3%
This trial studied the effect of including mannanoligosaccharides (MOS, Bio-Mos®, Alltech Inc., USA) in the diet on the caecal volatile fatty acids (VFA) and pH of rabbits from 34 to 90 days of age. Three experimental diets were compared: control diet, zinc bacitracin (ZnBac) diet (control diet with 0.1 g ZnBac/kg feed) and MOS diet (control diet with 2.0 g MOS/kg feed). Rabbits were slaughtered at 34, 48, 69 and 90 days of age and caecal contents were collected and analyzed for dry matter, pH and VFA concentration. The empty caecum and caecal contents weights relative to live weight were also determined. Age affected (P<0.0001) VFA concentration and pH values in the caecum. The pH decreased with age whereas VFA concentration increased. Rabbits fed MOS had higher (P<0.05) VFA and tended (P=0.098) to had lower pH in the caecum than rabbits fed ZnBac and control diets. Acetic, propionic and butyric acids concentrations in the caecum increased with MOS but its molar proportions were similar among diets. Diet had no effect on empty caecum weight and caecal contents weight and dry matter concentration. There was no interaction effect between diet and age. From 34 to 90 days of age, VFA production was higher (P<0.05) in the caecum of rabbits fed MOS than in those fed ZnBac diet and control diet. The addition of MOS to the diet increased the VFA concentration in the caecum of growing rabbits from 34 to 90 days of age.

Effects of fibre level and dietary mannanoligosaccharides on digestibility, caecal volatile fatty acids and performances of growing rabbits. Animal Feed Science and Technology

Pinheiro, Victor; Guedes, Cristina; Outor-Monteiro, Divanildo; Mourão, José Luís
Fonte: Universidade de Trás-os-Montes e Alto Douro Publicador: Universidade de Trás-os-Montes e Alto Douro
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
96.27%
The current experiment with 3 trials aimed to study the effect of two levels of dietary fibre – high fibre (HF; 323 g aNDFom/kg) and low fibre (LF; 248 g aNDFom/kg) – and the effect of mannanoligosaccharides (MOS) addition (1 g/kg) to the LF diet (LFM) on the performances and health status of growing rabbits, digestibility and caecal fermentative characteristics. In the growth trial 132 rabbits of both sexes were used (11 cages with 4 rabbits per treatment) from weaning (32 days of age) to slaughter (67 days of age). Rabbits fed HF diet showed a significantly higher weight gain and live weight at 67 days than rabbits fed LF diet (2032 g vs. 1935 g) (P<0.05). Feed and digestible energy intake increased with dietary fibre level (P<0.05). During the growing period rabbits fed HF diet had a feed intake 26% higher than those fed LF diet. Feed efficiency ratio was worse in HF animals (0.334 vs. 0.385; P<0.05). Addition of MOS to LF diet did not affect growth performance parameters (P>0.05). Mortality and morbidity rate were not affected by treatments. In the digestibility 24 rabbits from 46 to 51 days of age trial were used. The HF diet resulted in a significant (P<0.05) decrease in digestibility of dry matter, organic matter and protein while the aNDFom digestibility was not significantly different between diets (P>0.05). Supplementation with MOS had no effects on digestibility (P>0.05). In the 3rd trial the caecal traits were measured in 30 rabbits with 46 days of age that received the experimental diets in the previous 14 days. Caecal production of total volatile fatty acids (VFA)...

Inhibition of a Glucose-Limited Sequencing Fed-Batch Culture of Salmonella enterica Serovar Enteritidis by Volatile Fatty Acids Representative of the Ceca of Broiler Chickens

van der Wielen, Paul W. J. J.; Biesterveld, Steef; Lipman, Len J. A.; van Knapen, Frans
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /04/2001 EN
Relevância na Pesquisa
66.47%
The effects of concentrations of volatile fatty acids on an anaerobic, glucose-limited, and pH-controlled growing culture of Salmonella enterica serovar Enteritidis were studied. Suddenly increasing volatile fatty acids to the concentrations representative of the ceca of 15-day-old broiler chickens caused washout of serovar Enteritidis. In contrast, a sudden increase to the volatile fatty acid concentrations representative of the ceca of younger broiler chickens caused a reduction in the biomass but not washout. Gradually increasing volatile fatty acids caused a gradual decrease in the biomass of serovar Enteritidis. We conclude that the concentrations of volatile fatty acids present in the ceca of broilers with a mature microflora can cause washout of serovar Enteritidis in an in vitro system mimicking cecal ecophysiology.

Role of Volatile Fatty Acids in Development of the Cecal Microflora in Broiler Chickens during Growth

van der Wielen, Paul W. J. J.; Biesterveld, Steef; Notermans, Servé; Hofstra, Harm; Urlings, Bert A. P.; van Knapen, Frans
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /06/2000 EN
Relevância na Pesquisa
66.51%
It is known that volatile fatty acids can inhibit growth of species of the family Enterobacteriaceae in vitro. However, whether these volatile fatty acids affect bacterial populations in the ceca of chickens is unknown. Therefore, a study was conducted to investigate if changes in volatile fatty acids in ceca of broiler chickens during growth affect bacterial populations. Results showed that members of the Enterobacteriaceae and enterococci are present in large numbers in 3-day-old broilers and start to decrease when broilers grow older. Lactobacilli are present in large numbers as well in 3-day-old broilers, but they remain stable during the growth of broilers. Acetate, butyrate, and propionate increase from undetectable levels in 1-day-old broilers to high concentrations in 15-day-old broilers, after which they stabilize. Significant negative correlations could be calculated between numbers of Enterobacteriaceae and concentrations of undissociated acetate, propionate, and butyrate. Furthermore, pure cultures of Enterobacteriaceae isolated from the ceca were grown in the presence of volatile fatty acids. Growth rates and maximal optical density decreased when these strains grew in the presence of increasing volatile fatty acid concentrations. It is concluded that volatile fatty acids are responsible for the reduction in numbers of Enterobacteriaceae in the ceca of broiler chickens during growth.

Role of volatile fatty acids in colonization resistance to Clostridium difficile.

Rolfe, R D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1984 EN
Relevância na Pesquisa
66.56%
The in vitro inhibition of Clostridium difficile by volatile fatty acids was correlated with the pH and concentrations of volatile fatty acids in the ceca of hamsters of different ages. The concentrations of cecal volatile fatty acids increased with the age of the animals. Maximum concentrations of individual volatile fatty acids were attained when the animals were ca. 19 days old, with acetic, propionic, and butyric acids occurring in the highest concentrations (72, 16, and 32 microequivalents/g of cecum, respectively). The cecal pH was approximately the same in hamsters of all ages (pH 6.6 to 7.0). Only butyric acid reached a concentration in the ceca of hamsters which was inhibitory to the in vitro multiplication of C. difficile. This inhibitory concentration was attained when the animals were ca. 19 days of age. When mixtures of volatile fatty acids were prepared at concentrations equal to those present in the ceca of hamsters, there was a direct correlation between the in vitro inhibitory activity of the volatile fatty acids and the susceptibility of hamsters 4 days of age or older to C. difficile intestinal colonization. The resistance of hamsters less than 4 days of age to C. difficile intestinal colonization appears to be due to factors other than volatile fatty acids.

Quantitative gas chromatographic analysis of volatile fatty acids in spent culture media and body fluids.

van den Bogaard, A E; Hazen, M J; Van Boven, C P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1986 EN
Relevância na Pesquisa
66.35%
Gas chromatographic analysis of volatile fatty acids for identification of obligately anaerobic bacteria and for presumptive diagnosis of anaerobic infections is now widely practiced. However, it is difficult to compare data because only a qualitative analysis is done or only chromatograms are presented instead of quantitative data on volatile fatty acid production. We compared three stationary phases for volatile fatty acid analysis of aqueous solutions and four methods of pretreating samples for gas chromatography. Quantitative analysis could be done accurately by using Carbowax as the stationary phase after pretreatment of spent culture media with Dowex columns. If only qualitative analysis is required (e.g., for presumptive diagnosis of anaerobic infections), ether extraction and headspace analysis are equally suitable. The overall variation coefficient for volatile fatty acid production by four reference strains of obligately anaerobic bacteria after 24 h of incubation was approximately 10%.

METABOLIC FUNCTION OF BRANCHED-CHAIN VOLATILE FATTY ACIDS, GROWTH FACTORS FOR RUMINOCOCCI II. : Biosynthesis of Higher Branched-Chain Fatty Acids and Aldehydes

Allison, M. J.; Bryant, M. P.; Katz, I.; Keeney, M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1962 EN
Relevância na Pesquisa
66.39%
Allison, M. J. (Dairy Cattle Research Branch, USDA, Beltsville, Md.), M. P. Bryant, I. Katz, and M. Keeney. Metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. II. Biosynthesis of higher branched-chain fatty acids and aldehydes. J. Bacteriol. 83:1084–1093. 1962.—A number of strains of rumen bacteria require branched-chain volatile fatty acids for growth. A strain of Ruminococcus flavefaciens that requires either isovalerate or isobutyrate incorporates radioactive carbon from isovalerate-1-C14 and isovalerate-3-C14 into leucine and into the lipid fraction of the cells. Evidence obtained by both paper and gas chromatography indicated that most of the label in the lipid of cells grown in isovalerate-1-C14 was in a branched-chain 15-carbon fatty acid, with some in a 17-carbon acid; about 7.5% of the C14 was recovered in a branched-chain 15-carbon aldehyde. The aldehydes were in the phospholipid fraction and were presumably present as plasmalogen.

Volatile fatty acids and aerobic flora in the gastrointestinal tract of mice under various conditions.

Byrne, B M; Dankert, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1979 EN
Relevância na Pesquisa
66.43%
Volatile fatty acids are reported to exert a repressive effect upon Enterobacteriaceae and Pseudomonas species in vitro and in vivo in young mice. The mean total volatile fatty acid concentration in the cecal samples of conventional mice fed ad libitum was 81.7 mumol/g (wet weight), which is antibacterial in vitro, and in the rectal samples it was 41.1 mumol/g (wet weight). The mean count of Enterobacteriaceae in the cecum was only 10(2)/g, whereas in the rectum it was 10(5)/g. Volatile fatty acid levels were influenced by food intake and increased to peak levels approximately 6 to 10 h after eating and then declined. In mice fasted for 17 h, the butyric acid concentration was considerably lower and the number of cecal samples positive for Enterobacteriaceae increased. When fasted for 4 days, mice had extremely low cecal and rectal volatile fatty acid concentrations and the Enterobacteriaceae and enterococci counts increased to mean of 2 x 10(6)/g and 3 x 10(6)/g, respectively, in the cecum and to means of 10(7) and 5 x 10(6)/g in the rectum. We conclude that volatile fatty acids are probably one of the many interference mechanisms which are involved with control of the levels of Enterobacteriaceae (and enterococci) in the large intestine of mice.

Changes in the Mouse Intestinal Microflora During Weaning: Role of Volatile Fatty Acids

Lee, Adrian; Gemmell, Erica
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1972 EN
Relevância na Pesquisa
66.39%
The influence of volatile fatty acids on the ecology of the bacterial flora of the mouse intestinal tract has been studied in three situations where large fluctuations in the composition of the microflora have been observed. Young mice were shown to ingest solid food particles when 11 days old; this correlated with the appearance of strictly anaerobic fusiform bacilli in the intestinal lumen and a 10,000-fold decrease in numbers of coliform bacilli. Over the same period, volatile fatty acids were shown by gas-liquid chromatography to appear in the intestinal content. It is suggested that the fusiform bacilli are responsible for the presence of the volatile acids (especially butyric acid) which exert an inhibitory effect on the coliform bacteria, resulting in the decline in numbers. When germ-free mice are placed in a specific pathogen-free mouse colony, changes in the intestinal flora occurred which were similar to those observed in the young mice approaching weaning. Once again, the decline in the coliform population correlated with the appearance of significant levels of butyric acid in the large intestine. In a further series of experiments, mice were fed penicillin and levels of the intestinal fatty acids were measured. The antibiotic eliminated the anaerobic fusiforms from the intestine...

Detection of anaerobic wound infection by analysis of pus swabs for volatile fatty acids by gas-liquid chromatography.

Reed, P J; Sanderson, P J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1979 EN
Relevância na Pesquisa
66.49%
Swabs were able to absorb enough extractable volatile fatty acids from broth cultures of anaerobic organisms for detection and analysis by gas-liquid chromatography (GLC). Similarly, volatile fatty acids were often detected in swabs dipped into liquid pus. Fifty-three liquid pus specimens were then investigated fully to determine if GLC analysis of swab samples gave the same result as microbial culture of the specimens and GLC analysis of the liquid pus. Anaerobic bacteria failed to grow from 36 and volatile fatty acids were not extracted from swabs of 31 of these pus samples but were extracted from swabs of five. Anaerobic bacteria were isolated from 17 of the specimens, and in 15, volatile fatty acids were also detected in the swab samples; in two, volatile fatty acids were absent from both swab samples and liquid pus. In this study, results by culture and GLC analysis of swabs were similar in 87% of specimens.

Activation of volatile fatty acids in bovine liver and rumen epithelium. Evidence for control by autoregulation

Ash, R.; Baird, G. D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1973 EN
Relevância na Pesquisa
66.38%
1. The total capacities of homogenates of bovine liver and rumen epithelium to activate acetate, propionate and butyrate were determined. 2. Activating capacities were assayed by measuring the rate of formation of the corresponding CoA esters. The methods used for determining the concentrations of the CoA esters allowed the CoA esters of acetate, propionate and butyrate to be distinguished. It was thus possible to investigate the effect of the presence of a second volatile fatty acid on the rate at which a given volatile fatty acid was activated. 3. The propionate-activating capacity in rumen epithelium was decreased by about 87% in the presence of butyrate, the acetate-activating capacity in liver was decreased by about 55% in the presence of either propionate or butyrate, and the butyrate-activating capacity in liver was decreased by about 40–50% in the presence of propionate. 4. All three activating capacities in liver appeared to be located in the mitochondrial matrix and membrane. The three activating capacities had similar locations to each other in rumen epithelium as well, although in this case activity was more evenly divided between the mitochondria and the cytoplasm. 5. The relative activating capacities towards the volatile fatty acids in the two tissues...

Determination of volatile fatty acids in plasma after ethanolic extraction

Remesy, Christian; Demigne, Christian
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1974 EN
Relevância na Pesquisa
66.45%
1. A new rapid micro-method for measuring plasma volatile fatty acids is described. The volatile fatty acids are extracted from plasma with ethanol in the presence of a known quantity of internal standard (sodium isobutyrate). After evaporation of the ethanolic solution of the sodium salts, the residue is dissolved in a dilute solution of orthophosphoric acid to permit analysis by g.l.c. 2. A technique of g.l.c. analysis is described which permits the separation of all the volatile fatty acids from the other plasma constituents at temperatures below 100°C in 5 min. 3. Steam-distillation techniques are unsatisfactory when the acetic acid concentrations in the plasma are below 0.2mm. Heating of a number of plasma constituents in acid conditions gives rise to acetic acid. 4. The binding of volatile fatty acids to plasma proteins was studied; this binding is negligible for acetic acid, but increases with the length of the fatty acid carbon chain. 5. The limits of use of the method and the physiological implications are discussed.

Effect in the cow of intraruminal infusions of volatile fatty acids and of lactic acid on the secretion of the component fatty acids of the milk fat and on the composition of blood

Storry, J. E.; Rook, J. A. F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1965 EN
Relevância na Pesquisa
66.33%
1. The effects in the cow of intraruminal infusions of acetic acid, propionic acid or butyric acid on the secretion of the component fatty acids of the milk fat, and of these acids and of lactic acid on the composition of the blood plasma of the jugular vein, have been studied. 2. The infusion of acetic acid or butyric acid increased the yield of the C4–C16 acids of milk fat but decreased the yield of C18 acids. The infusion of propionic acid decreased the yields of all major component acids except palmitic acid and possibly lauric acid. 3. The changes in the concentrations in blood plasma of glucose and of ketone bodies were consistent with the glucogenic effect of propionic acid and the ketogenic effects of butyric acid and acetic acid. The effects of lactic acid were not consistent from cow to cow. Only with the infusion of acetic acid was a significant increase in the concentration of total volatile fatty acids in blood plasma found. Infusions of butyric acid and of propionic acid tended to depress the concentration of citric acid in the blood plasma and infusion of acetic acid increased it. No consistent effects of the infused acids on the concentration in blood plasma of esterified cholesterol, free cholesterol, triglyceride or phospholipid were observed. 4. The possibility is discussed that the effects of the infused acids on milk-fat secretion are caused through an alteration of the concentrations of precursors of milk fat in mammary arterial blood.

Volatile fatty acids in the faeces of patients in `germ-free' isolation

Gompertz, D.; Brooks, A. P.; Gaya, H.; Spiers, A. S. D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1973 EN
Relevância na Pesquisa
66.34%
Faecal volatile fatty acids represent the end products of the metabolism of the anaerobic flora of the large bowel. The excretion of these volatile acids has been investigated in five leukaemic patients maintained in plastic `germ-free' isolators. Under `isolator' conditions there is a pronounced fall in volatile fatty acid excretion. The possibility that the measurement of these acids may be used to monitor anaerobic overgrowth and recolonization in these patients is discussed.

Analysis by gas liquid chromatography of production of volatile fatty acids by anaerobic bacteria grown on solid medium.

Wiggins, R J; Wilks, M; Tabaqchali, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1985 EN
Relevância na Pesquisa
66.37%
Volatile fatty acids produced in Robertson's cooked meat medium by a range of clinically relevant anaerobes were compared by gas liquid chromatography with those produced in blood agar. The same volatile fatty acid profiles were obtained in both media, although the concentration of acids was lower in blood agar. We conclude that detection of volatile fatty acids from a pure culture of an organism on solid medium is practicable and offers advantages over the conventional technique.

Effects of adding unsaturated fatty acids on fatty acid composition of saccharomyces cerevisiae and major volatile compounds in wine

Duan,L.L.; Shi,Y.; Jiang,R.; Yang,Q.; Wang,Y.Q.; Liu,P.T.; Duan,C.Q.; Yan,G.L.
Fonte: South African Journal of Enology and Viticulture Publicador: South African Journal of Enology and Viticulture
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
Relevância na Pesquisa
66.43%
The synergistic influences of three unsaturated fatty acids (UFAs, namely linoleic acid, oleic acid and linolenic acid) on the fatty acid composition of Saccharomyces cerevisiae and major volatile compounds were investigated in synthetic grape juice. The addition of UFAs led to a corresponding increase in UFAs in the cellular lipid, which was accompanied by a reverse reduction in the content of medium-chain saturated fatty acids (C6:0 to C14:0) and little variation in that of long-chain saturated fatty acids (C16:0 to C24:0). The supplementation of UFAs considerably improved yeast growth and fermentation activity and, in particular, increased the concentrations of most volatile compounds in wine, including higher alcohols (2-phenylethanol, 2-methyl-1-propanol and 3-(methylthio)-1-propanol), medium-chain fatty acids (butanoic acid, hexanoic acid and octanoic acid), acetate esters (isoamyl acetate and 2-phenylethyl acetate) and all ethyl esters. Remarkable linear relationships were further found between ethyl esters and the concentration of the added UFAs (R² from 0.909 to 0.996), which significantly intensified the fruity, flowery and sweet attributes of the final wine, as assessed by calculating the odour activity values. Our results suggest that rationally increasing the concentration of UFAs is not only a practical method to improve yeast fermentation activity...