Laxative effect of gastric emptying in normal horses

An enormous important part of conservative therapy on cecal and colonic impaction is the use of laxatives in colic horses. The objective of this study was to investigate the effect of stomach emptying induced by three different volumes of laxatives. Xylose was used as a transit marker. Protocol 1 included 10 % xylose solution (0.5 g/kg b.w.) and an isotonic solution of sodium sulfate (140 g/101water/500 kg b.w.); protocol 2: xylose solution and 10 1 water/500 kg b.w.; protocol 3: xylose solution and an isotonic solution of 370 g magnesium sulfate/101 water/500 kg b.w.; protocol 4: 2 1 water/500 kg b.w. and protocol 5: 2 1 paraffinum liquidum /500 kg b.w. The solution of every single protocol was administered by nasogastric tube to 5 fasting normal adult horses. Between each protocol taken there was one week time off. Serum samples were collected before application and afterwards in intervals of 10 minutes up to 120 minutes post applicationern as well as up to 240 minutes in intervals of 30 minutes. A photometric method was used to detect xylose in serum samples. The time (T-max) until reaching the highest concentration of xylose (C-max) was taken as a marker of stomach emptying. After these examinations Tmax amounts in protocol 1 to 74 +/- 15; in protocol 2 to 66.3 +/- 7; in protocol 3 to 86.7 +/- 20; in protocol 4 to 64 +/- 14 and in protocol 5 to 92 +/- 17 min. The isotonic solution of sodium sulfate in the volume of 101 does not lead to a delay of stomach emptying.