Pattern of motility and flow of digesta in the forestomach of the Llama (Lama guanacoe f.glama)

Summary

A study of the pattern of stomach motility was made in five conscious llamas. Motility was recorded continuously by X-radiography, electromyography and/or balloons with pressure transducers, and correlated with outflow of fore-stomach contents measured by a thermistor.

The llama forestomach showed a rhythmic pattern of contractions (motility cycle). A single cycle lasted about 82 s. Evidence is presented that each cycle comprises a single A- and numerous B-contraction sequences. Each motility cycle started with an A-sequence which began with a contraction of the canal between compartment 2 (C2) and compartment 3 (C3). A vigorous contraction of C2 followed, as the pressure in the canal fell below the baseline, then a contraction of the caudal sac of compartment 1 (C1) and another contraction of the canal occurred. The B-sequence of contractions began with a contraction of the cranial sac of C1 at the same time as the second canal contraction, followed by a weak contraction of C2 and finally a contraction of the caudal sac of C1. This B-sequence was repeated a number of times in each motility cycle.

Passage of contents from C2 to C3 only occurred as the canal relaxed during the A-contraction.

Continuous aborally-directed segmention and peristaltic-like movements were recorded in C3. These contractions occurred at 10 min⁻¹ in the proximal part, and at 5 min⁻¹ in the distal part where they were strongest. In the hind stomach mixing movements could be seen. At the border between C3 and the hind stomach, within a length of 10 cm the pH fell from 6 to less than 2. No reflux of contents was observed from the hind stomach to C3.