Rapid method for the gas-chromatographic determination of volatile fatty acids in rumen fluid

Abstract

A rapid method for the gas-chromatographic determination of volatile fatty acids (VFA, C2 to C5) in rumen fluid with the aid of flame ionization detection is based on the direct analysis of the rumen fluid without previous extraction. After filtration of the rumen fluid, metaphosphoric acid is added to precipitate proteins, and formic acid (5 %) is used to eliminate the disturbing "ghosting" effect. The clear supernatant obtained after centrifugation is injected directly into the column. The analysis of one rumen sample requires about 8 minutes. For the quantitative determination, a nonautomatic integrator is used. The individual VFA are calculated by comparing with a standard. The recovery and precision of the gas-chromatographic techniques are discussed.The energy requirements of ruminants are mainly covered by absorption through the rumen wall of the short-chain fatty acids. The molecular proportion of the different VFA is closely related to energy utilization and the animal's production. For nutritionists, a rapid and accurate method for fatty acid analysis in rumen fluid is therefore of great importance. In recent years, gas chromatography has appeared to be the most suitable technique.James and Martin (1952) perfected the first gas-chromatographic separation of both straight-and branchedchain lower fatty acids. Because of their volatility, the lower fatty acids were analyzed as esters, and later the acids themselves were determined directly.

Effect of anaerobic fungi on in vitro feed digestion by mixed rumen microflora of buffalo

“…VFA were estimated using a Nucon-5765 gas chromatograph equipped with a flame ionization detector as per the method described by Cottyn and Boucque [20], using a glass column of 4 feet in length and 1.8 mm diameter packed with chromosorb 101, with gas flow rates for nitrogen, hydrogen and air as 30, 30 and 320 mL/min, respectively.…”

Effect of white-rot basidiomycetes-treated wheat straw on rumen fermentation in artificial rumen

“…The residue was washed twice with water, and was dried to constant weight at 105 °C. The concentrations of volatile fatty acids (VFA) in the effluent were determined by the gas chromatography procedure (Cottyn and Boucque, 1968) using crotonic acid as the internal standard in the Perkin-Elmer 8500 gas chromatograph. The volumes of gas produced were measured with a gas meter and the methane and C0 2 gases were analyzed in a Chrom 4 gas chromatograph as reported by Czerkawski and Clapperton (1968).…”

Porphyromonas loveana sp. nov., isolated from the oral cavity of Australian marsupials

“…nov., P. gingivalis ATCC 33277 T and P. gulae ATCC 51700 T were grown in peptone/yeast/glucose medium and analysed by GLC (Cottyn & Boucque, 1968;Ottenstein & Bartley, 1971;Playne, 1985). All isolates showed the same major metabolic end products, which were acetic, propionic, butyric and isovaleric acids, with minor production of isobutyric, succinic and phenylacetic acids (Table 1).…”