Effect of Dietary Fiber Level on the Healing of Gastric Ulcers in Horses

Abstract

Equine Gastric Ulcer Syndrome (EGUS) is estimated to occur in 53 to 93% of performance horses. Feeding practices, management, and dietary composition have all been suggested to impact the frequency and severity of EGUS. The aim of this study was to determine if alteration of fiber content within the concentrate portion of the diet alters gastric ulcer scores. The effects on healing of a commercially available high fiber and low fiber feeds were compared. The experiment was conducted in two phases. During phase I, 21 mature Quarter Horses were managed under a 7 d feeding/fasting regimen to induce gastric ulceration. Horses were fed ad libitum grass hay for 24 hr, followed by 24 h fasting. After d 7, gastroscopic examination was performed to determine ulcer scores of the greater (GC) and lesser curvature (LC) of the stomach. Following gastroscopy, 16 horses with an ulcer score of ≥ 1 in GC and ≥ 2 in LC were selected for phase II. Horses were pair matched by weight, gastric ulcer score, and type and assigned to either the high fiber (HF) or low fiber group (LF) in a randomized block design. Each group was fed their respective ration for 30 d in 50:50 ratio with grass hay at 2% of BW in DMI. Gastroscopic examination was performed on d 0, d 15, and d 30 of phase II to evaluate the occurrence of gastric ulceration. During this time, a stomach fluid sample was also extracted from the gastric antrum of the stomach and pH was recorded immediately. Data were analyzed with Proc GLM (SAS) suitable for repeated measures. Gastric ulcer scores in both groups had improved from d 0 to 15 and d 15 to 30 (P < 0.05). The LF group had a greater stomach pH of 4.46 (P < 0.05) compared to 2.92 in the HF group on d 15. The results of this study suggest that an increase in fiber level in the concentrate portion of the diet does not alter the rate of gastric ulcer healing using an induced ulcer model.