A comparison between ytterbium acetate, ruthenium phenanthroline and indigestible acid detergent fibre in a double-marker system for intestinal flow measurements in steers

Abstract

S U M M A R YThree double-marker systems were used in cannulated steers offered straw-based diets supplemented with barley, fishmeal or a combination of both, in an attempt to reduce the risks of misinterpreting biological results based on calculations of digesta flows using markers. Ruthenium phenanthroline (Ru-phe), ytterbium acetate (Yb-ac) and the indigestible acid detergent fibre fraction (IADF) were used as markers of the particulate phase of digesta in conjunction with Cr-EDTA as a liquid-phase marker to estimate duodenal and ileal digesta flows. The present paper presents the difficulties met in the application of marker techniques.The particulate marker used in a double-marker system for calculation of nutrient flow modified the degree of statistical significance observed for dietary treatment effects on digesta flow parameters.The data suggest that the type of diet used affects the behaviour of individual markers in different ways and could incur some bias in the results. It is hypothesized that the physical and chemical characteristics of digesta, in different dietary conditions, can be responsible for differential attachment of markers to particles of the solid phase. In such cases, the distinction made in the double-marker technique between particulate and liquid phases may not be sufficient to correct for lack of representativeness of digesta contents sampled from T-shaped cannulae.For the diets studied it was concluded that the interpretation of digestion parameters should be based on both Ru-phe and Yb-ac results.

Manipulation of nitrogen digestion by sheep using defaunation and various nitrogen supplementation regimens.

“…Except for determining digesta retention time, usage of chromic oxide for measuring nutrient flow and digestion generally is acceptable (Merchen, 1988). Although a dual marker system has been suggested (Faichney, 1975) in conjunction with the use of simple T cannulas, its applicability remains questionable (Ortigues et al, 1990).…”

Determination of digesta flow entering the omasal canal of dairy cows using different marker systems

“…Ytterbium. Yb has been used extensively as a solidphase marker within double-marker systems (for example, Ortigues et al 1990;Huhtanen et al 1997) following the observation that proportionately 0•93 of administered Yb is associated with particulate matter in duodenal digesta (Siddons et al 1985). Use of alternative procedures that provide a more rigorous labelling of Yb with fibre fractions (Ellis et al 2002) could be expected to improve the association with particulate matter.…”

Effect of non-uniform distribution of particle-associated markers on the measurement of duodenal digesta flow by the double-marker technique

“…The results of Ortigues et al (1990) show differences of a similar order of magnitude but, because their sampling procedure resulted in negative R values, the differences were in the opposite direction. Thus R calculated using Yb was 20 % less and dry matter flow was 5 % greater than when Ru-phen was used.…”

“…However, Ortigues et al (1990) modified the double-marker method by imposing the assumption that their solute marker, CrEDTA, remained totally in solution, although it is known that some CrEDTA does adsorb to paniculate matter (Warner 1969;Faichney 1975). This adsorption leads to a higher apparent concentration of CrEDTA in digesta water than in fluid phase water in samples of abomasal and duodenal digesta.…”