THE USE OF DOSED AND HERBAGE N-ALKANES AS MARKERS FOR THE DETERMINATION OF DIGESTIVE STRATEGIES OF CAPTIVE GIRAFFES (GIRAFFA-CAMELOPARDALIS)

Selected aspects of digestion in captive giraffes were investigated in two trials with a type of marker that is new for digestive studies in non-domestic species. n-Alkanes were used as internal and external ma rkers. In Trial I, diet composition, intake, and digestibility were di rectly measured and estimated with the marker. Six giraffes were dosed once daily for 3 weeks with labeled pellets containing 3,800 ppm of e ach C-28, C-32, and C-36 alkanes at similar to 100 mg/100 kg bodyweigh t. Intake of cabbage, browse, and a cattle pellet could accurately be estimated with the alkane method. For an oat/wheat mix and clover hay, however, there were large differences between directly measured intak es and those obtained using the alkane method, with the alkane method substantially underestimating. In Trial 2 mean retention times (MRTs) of fluid and particle phase were estimated. Three subadult giraffes we re dosed once with cobalt-ethylenediamine tetraacetic acid (Co-EDTA) ( 260 mg) and alkanes C-29 (140 mg) and C-36 (370 mg). The average MRT f or the fluid phase (Co-EDTA) was 31 hr and for the particle phase (alk anes) was 41 hr (C-36) and 43 h (C-29) This study showed that n-alkane s have potential as markers for investigating digestive strategies in non-domestic herbivores. (C) 1998 Wiley-Liss, Inc.