Circadian variation in composition of duodenal and ileal digesta from pigs fitted with T-cannulas

Abstract

ABSTRACTCircadian variation in the composition of digesta was examined in pigs fitted with replaceable T-cannulas in the proximal duodenum and terminal ileum. The pigs were fed twice daily with a cereal-based diet containing Cr2O3, as a marker. Digesta were collected hourly for 16 h following morning feeding (pig live weight (LW) 25 and 65 kg) or as a 12-h composite collection (pig LW 45 kg), and analysed for pH, dry matter (DM), ash, crude fat, crude protein, starch, neutral-detergent fibre (NDF) and Cr2O3,.No statistically significant differences were found in the composition of digesta from pigs weighing 25 or 65 kg LW. Calculated relative to Cr2O3, recoveries in 12-h composite samples of duodenal and (ileal) digesta were 1·19 (0·34) for DM, 1·28 (0·31) for crude protein, 0·97 (0·05) for starch and 0·93 (0·79) for NDF. Composition of both duodenal and ileal digesta varied considerably during the sampling period and was particularly influenced by giving food. Between-hour coefficients of variation for the samples taken hourly were, in general, greater at the duodenum (mean 017) than at the ileum (mean 0·11), while mean within-hour (between pigs) coefficients of variation (0·19 and 0·18, respectively) were greater than those between hours. The Cr2O3 marker generally followed the flow of dietary matter through the gastrointestinal tract, although there was an indication of a partial separation of NDF from other dietary components in the stomach. Composition of the 12-h composite samples of digesta did not differ from that of the mean of the samples taken hourly for 16 h.