A technique for the collection and the study of biochemical and microbial characteristics of postprandial gastric contents from conscious horses

The objective of this study was to collect gastric contents from conscious horses via naso-gastric (NG) intubation to facilitate the study of the microbial ecosystem of the equine stomach. Six healthy Arabian horses (from 3 to 5 years old) were used according the following procedure. Two hours after the morning feeding, horses were sedated and restrained for NG intubation. A video-endoscope passed through a NG tube was used to position the NG tube in contact with the digesta. The video-endoscope was removed, the digesta were aspirated through the NG tube and collected. Each horse was sampled two times on 2 days according to the protocol. Volume, pH, temperature, dry matter (DM), total anaerobes and lactobacilli microbial populations, volatile fatty acids (VFA), ammonia (NH3), d-glucose and d-/l-lactate concentrations were measured on each sample. Repeatability and reproducibility were calculated for each variable. The technique allowed collection of 190 ± 68 ml of gastric contents during each sampling time, which provided the necessary quantities for the various analyses performed. Repeatability of the variables studied ranged from 0.39 for DM up to 0.90 for lactobacilli counts, whereas reproducibility ranged from 0.19 for volume to 0.89 for d-glucose concentration. Paired with classical endoscopic exam for equine gastric ulcer syndrome (EGUS) diagnosis, this collection technique can be easily used by scientists and veterinarians to study the relationship between some major chyme characteristics such as pH, microbial populations and lactate, and the occurrence of diseases such as EGUS.