A comparison of total collection and marker technique for the measurement of apparent digestibility of diets for growing pigs

Use of markers for the measurement of digestibility is a less labour intens ive method than total faecal collection. The objectives of the present stud y were: (1) to evaluate chromic oxide (Cr2O3), titanium dioxide (TiO2) and acid-insoluble ash (AIA) markers for the calculation of digestibility and ( 2) to examine the reliability of grab sampling as a technique for measuring digestibility in group-housed animals. For marker comparison, eight entire males were housed in individual metabolism crates and offered a cereal-bas ed diet. Pigs were randomly allotted to treatments for total collection per iod one, four to the diet with 1 g chromic oxide and 1 g titanium dioxide a dded per kilogram (Treatment A) and four to the same the diet without marke r (Treatment B). During total collection period two, the treatments were re versed. AIA was measured for all animals in crates. For grab sampling study , grouped-housed animals (13-14 per pen) were fed the same cereal-based die t as for marker comparison above and AIA marker was used. Faecal samples we re taken from a representative number of animals (minimum eight) in a pen w hile held in a weighing scales. All feed and faeces samples were analysed f or marker contend and digestibility. Feed analysis showed 0.93 g/kg of Cr2O 3 and 1.02 g/kg of TiO2 added to the diet. Faecal marker recovery was 96, 9 2.3 and 99.9% (S.E. 2.27) for Cr2O3, TiO2 and AIA, respectively. Mean energ y digestibility values were 0.858, 0.848, 0.844 and 0.855 (S.E. 0.003, P < 0.01) for total collection, Cr2O3, TiO2, AIA, respectively. Energy digestib ility coefficients were 0.852 and 0.861 (S.E. 0.004, P > 0.10) for total co llection las measured in marker comparison) and grab sampled animals, respe ctively. In conclusion, acid-insoluble is a reliable marker for the measure ment of digestibility and grab sampling offers a rapid and reliable alterna tive to the labour intensive metabolism crate method. (C) 2001 Elsevier Sci ence B.V. All rights reserved.