Rate of passage in the rabbit digestive tract: influence of marker dosing time, ileal cannulation and marker type
A control group of 5 adult rabbits and a group of 4 ileocannulated rabbits, fed ad libitum were used to assess the effect of marker dosing time, marker type (Ytterbium vs Cerium labelled cellwall) and the effect of the ileal cannulation, on measurement of passage rate (RPM). The passage rate of particles labelled with 169 Yb was equal to those labelled with 141 Ce, and allowed the comparison of RPM obtained with these two markers given at different times to the animals.
In our experimental conditions, over 70% percent of the animals showed no hard faeces excretion between 10:00 and 16:00, because of soft faeces excretion during this period. The total mean retention time (MRT) did not vary significantly when the marker dosing time took place out of the period of caecotrophy (meanly 20.3h). But a 25% reduction in MRT (-5.2h) was observed when marker was given during caecotrophy (at 13:00) compared to a dosing time at the beginning of the caecotrophy (11 :00). This decrease in MRT values at 13:00 was partly due to a shorter (-1.5h) minimal transit time (TTm). When the marker was given befare caecotrophy (8:00) or at the beginning of the caecotrophy (11 :00), a part of the labelled particles could be incorporated directly into the soft faeces and ingested, thus contributing to increase the MRT value and particularly the TTm value. For a dosing time after caecotrophy, the labelled particles spent more time in the caeco-colic segment. In addition, the variability of rate of passage parameters appeared to be lower for a dosing time placed at the beginning of the caecotrophy (11 :00). Rabbits having an ileal cannula showed a slight lower (-15%) feed intake and a higher faecal digestibility (+2 units). No significant difference in transit however was registered between conventional and cannulated animals.
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Official journal of the World Rabbit Science Association (WRSA)
e-ISSN: 1989-8886 ISSN: 1257-5011 https://doi.org/10.4995/wrs