This study aimed to evaluate buffer capacity (BC), pH and faeces consistency of horses submitted to dietetic starch overload. Six crossbreed mature horses were submitted to starch overload with gastric infusion of 17.6g starch kg-1 body weight through nasogastric tube. Faecal samples were collected, before and at 4, 8, 12, 16, 20, 24, 28, 32 and 36 hours post-overload, and immediately submitted to evaluation of pH, BC and consistency. The pH data were compared by t student test (P<0.05). The BC and fecal consistency were compared by Kruskal-Wallis test (P<0.05) and submitted to regression analysis and Spearman correlation in function of the time after overload. There was faecal pH decreased along 36 hours post-overload (P>0.05), with means values varying from 6.09 to 4.46. Based on the model pH = 6.083 - 0.003t - 0.001t² (R² = 0.634), faecal pH decreased 0.004 per hour, 0.028 to each four hours and 1.404 at 36 hours after overload, respectively. As pH, faeces BC decreased (P<0.05) in function of the time after overload. Positive relationship was observed (r = 0.65; P<0.0001) between pH and BC of faeces. All horses presented normal consistency faeces (score 3) until eight hours after overload, following by reduction (P<0.05) up to 36 hours. Results demonstrated that starch overload reduce faecal consistency, buffer capacity and pH in horses faeces.
carbohydrate; horses; diets; faecal pH
