The chromium-51 complex of ethylenediamine tetraacetic acid as a soluble rumen marker

Abstract

In experiments on digestive function in ruminants, markers can be used to estimate the rate of movement of digesta, the volume of a viscus and the rates of absorption of solutes from the gut. The most widely used water-soluble marker is polyethylene glycol (PEG), which was introduced by Sperber, HydCn & Ekman (1953). They found that the polymer with mean molecular weight 4000 was not degraded in the gut or absorbed, and described the use of PEG for the three purposes set out above.HydCn (1961) has given a full mathematical treatment of the principles involved in the use of soluble markers to measure the rate of flow and volume of rumen fluid, and has indicated the inherent limitations of the method. He found that PEG gave a satisfactory estimate of rumen fluid volume (PEG space was approximately 95 % of rumen water volume); in experiments of long duration (i.e. days or weeks), the flow rate could be calculated from the rate of fall in concentration of the marker; and in short-term experiments, the flow could be estimated from the amount of reference substance that had disappeared from the rumen during the experiment and the mean concentration of the marker in the rumen fluid.However, a serious limitation in the use of PEG is the lack of a specific, sensitive and accurate method of analysis. All published methods have been based on precipitation from aqueous solution with subsequent gravimetric or turbidimetric measurement. Analytical difficulties have been recorded by Smith (1958), and Corbett, Greenhalgh, Gwym & Walker (19 j8) obtained incomplete recovery of PEG from the faeces of grazing cattle and sometimes from stall-fed cattle.An alternative reference substance was sought and radioactivity was selected as a ineans for sensitive and completely specific analysis. The complex of 51Cr with ethylenediamine tetraacetic acid (j1Cr EDTA) was tested and compared with PEG.The results which are reported here showed j3Cr EDTA to be a highly satisfactory soluble marker in sheep. E X P E R I M E N T A L AnimalsNine Merino wethers, one Merino ewe, and four cross-bred sheep were used. Five of the Merino wethers were 'normal', the rest of the sheep were fitted with rumen cannulas. The Merinos were fed once daily and were housed indoors in metabolism cages of the type described by Reis & Schinckel (1961). Faecal collections from the available at https://www.cambridge.org/core/terms. https://doi

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

“…Nutrient flow at the duodenum was estimated by the dual phase marker technique (Faichney, 1975) using chromium-EDTA (Cr-EDTA; Downes and McDonald, 1964) to mark the fluid phase and ytterbium acetate as the particulate phase marker. Solutions of Cr-EDTA (3420 mg Cr/ml) and ytterbium acetate (845 mg Yb/ml) were continuously infused, via separate infusion lines, into the reticulo-rumen by means of a multi-channel peristaltic pump (Minipuls 2; Gilson, France).…”

Recovery of intravenously infused chromium EDTA and lithium sulphate in the urine of cattle and their use as markers to measure urine volume

“…In support, Downes and McDonald (1964) also recorded 90% recovery of Cr in the urine of sheep after a single intravenous injection of 51 CrEDTA. This consistency in recovery provides confidence in the wider use of the non-radioactive form of CrEDTA as a marker with potential to estimate urine output.…”

“…Chromium complexed with ethylenediamine tetra-acetic acid (CrEDTA; Downes and -Present address: Department of Primary Industries and Fisheries, PO Box 6014, CQMC, Rockhampton, QLD 4702, Australia. E-mail: maree.bowen@ dpi.qld.gov.au McDonald, 1964;Stacy and Thorburn, 1966) and lithium salts (Suharyono, 1992;Dixon et al, 2003) have been investigated for suitability as markers to examine such factors as the rate of flow and volume of rumen fluid, and the intake of supplements, by ruminants. The application of these substances as intravenously administered markers for estimating urine output in grazing ruminants requires knowledge of the recovery of the marker in the urine and of the diurnal variation in marker concentration, or the metabolite : marker ratio, in the urine.…”

Effect of dietary molasses on the site and extent of digestion of nutrients in sheep fed broiler litter

“…The double marker technique (Faichney, 1975) was used for estimation of partial digestibility, with chromium (Cr-EDTA; Downes & McDonald, 1964) and ytterbium (Yb-acetate; Siddons et al, 1985) as liquid and particulate phase markers respectively. The Cr-EDTA and Yb-acetate were prepared according to the methods described by Morgan et al (1976), and predetermined daily doses were infused continuously into the rumen using a peristaltic pump.…”