The effect of a seaweed-derived calcium supplement on gastric juice pH in the horse.

Abstract Low gastric pH for extended periods of time can increase the risk of gastric ulceration in horses. Therefore, nutritional interventions that buffer stomach acid may be helpful to decrease ulcer risk. The objective of this trial was to evaluate whether the incorporation of calcified Lithothamnion corallioides and Phymatolithon calcareum (Calmin®; Celtic Sea Minerals, Cork, Ireland) into an equine ration would buffer equine gastric juice. Nine mature, Thoroughbred-cross horses including 6 geldings and 3 mares (524±49 kg) were housed in stalls and fed 2 kg/day of a texturized concentrate (Purina® Omolene 100®) and 1.5% BW grass hay/day. On testing days 0, 7 and 14, the horses received one of three dietary pelleted treatments (CON, MIN1x, MIN2x) in a randomized, crossover design. CON contained no added Calmin®, MIN1x provided Calmin® at a 1x concentration, and MIN2x provided a 2x dose. All horses underwent gastroscopy (Karl Storz, El Segundo, CA) prior to feeding the treatments, and at 2 and 4 hrs post-feeding. Gastric juice was aspirated and pH measured using a benchtop pH meter (ThermoOrion pH Meter Model 410A). Overall, there was a significant time effect (P