Volatile fatty acids VFA

In addition to these three main groups of organic components, volatile fatty acids (VFAs), amino acids, detergents, humic substances, organic fibers, etc., have been found. 

The following characteristics were analysed by standard methods (9) TS, volatile solids (VS), chemical oxygen demand (COD), Kjeldahl nitrogen (Kj-N) and ammoniacal nitrogen (NH3-N). The biochemical oxygen demand of whole slurry (BODw) was analysed by a dilution method (10). Volatile fatty acids (VFA) were analysed by gas... 

Odour quality depends not only on the sensitivity of the human nose but also on the subjectivity of the human language to be able to describe the odour (17). Some chemical characteristics of slurry have been compared to the slurry odour. A relationship between volatile fatty acids (VFA) and odour offensiveness of poultry manure was described by... 

This paper reports on the aspects of dust formation in livestock buildings, the material composition of the dust, the emission of dust-bome odourants like volatile fatty acids (VFA) and simple phenols and indoles from piggeries, the importance of particle-borne... 

These short-chain fatty acids are acetic, butyric, lactic and propionic acids, also known as volatile fatty acids, VFA. They are produced from fermentation of carbohydrate by microorganisms in the colon and oxidised by colonocytes or hepatocytes (see above and Chapter 4). Butyric acid is activated to produce butyryl-CoA, which is then degraded to acetyl-CoA by P-oxidation acetic acid is converted to acetyl-CoA for complete oxidation. Propionic acid is activated to form propionyl-CoA, which is then converted to succinate (Chapter 8). The fate of the latter is either oxidation or, conversion to glucose, via glu-coneogenesis in the liver. 

Work with cereals, performed by a number of researchers in diverse locations, has shown that the short-chain aliphatic or volatile fatty acids (VFA), especially acetic acid, are the only chemicals produced in sufficient quantities from decaying residues to be toxic in the field (59, 60, 6l, 62). VFA have also been... 

The effects of dietary FOS on the GI microflora of poultry are well documented. Flidaka et ol. (1991) found that consumption of 8 g FOS per day increased numbers of bifidobacteria, improved blood lipid profiles and suppressed putrefactive substances in the intestine. Patterson et d. (1997) found that caecal bifidobacteria concentrations increased 24-fold and lactobacilli populations increased 7-fold in young broilers with FOS. Bifidobacteria may inhibit other microbes because of a high production of volatile fatty acids (VFAs) or the secretion of bacteriocin-like peptides (Burel and Valat, 2007). The improvement in gut health status by dietary FOS supplementation often results in improved growth performance. Ammerman et d. (1988) demonstrated that the addition of dietary FOS at a level of 2.5 or 5.0g/kg diet improved feed efficiency over the period from 1 to 46 days of age. Mortality was reduced with the higher level. However, Waldroup et d. (1993) found that supplementing the diet of broilers with 3.75 g/kg FOS had few consistent effects on production parameters or carcass Sdmonella concentrations. 

Figure 4. Developments of cumulative hydrogen yield, pH value, volatile fatty acids (VFAs) and alcohols in the batch reactor during the conversion of the substrate to biohydrogen under the pretreated condition of microwave heating...

The general pathways for volatile fatty acid (VFA) formation seem to involve three phases ... 

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