Effect of molassed sugar beet pulp on nutrient utilisation and metabolic parameters during exercise.

Abstract

The aim of this study was to investigate the effect of partly replacing oats with molassed sugar beet pulp in a traditional hay/oat diet on nutrient utilisation and metabolic parameters in exercising horses. In a change-over experiment, 4 Standardbred geldings were fed a hay and oat-based diet (Oat diet) and a hay and oat-based diet where oats was partially replaced with molassed sugar beet pulp (MSBP diet). Each experimental period was 21 days during which total collection of faeces and urine was made and an exercise test (ET) performed. The crude fat digestibility was lower on the MSBP diet (P<0.05), while there were no differences in digestibility of other nutrients and energy and in the urinary excretion of nitrogen and energy. At rest plasma insulin were lower (P<0.05) 60 and 90 min postprandially on the MSBP diet, while no differences were found in plasma glucose and insulin between the diets during the ET. The peak plasma and muscle lactate values were lower (P<0.05) on the MSBP diet and the content of muscle glycogen was higher (P<0.05) after the ET on the MSBP diet. In conclusion, the metabolic response differed between diets giving a lower lactate response and a higher glycogen content in muscle after exercise on the MSBP diet. This suggests that the dietary carbohydrate composition may influence the rate of glycogenolysis with lactate production and support the hypothesis that MSBP can replace oats in a hay based diet without impairing nutrient utilisation and metabolic response in exercising horses.