Nutritional implications ofl-arabinose in pigs

Abstract

The pentose sugarl-arabinose is one of the most abundant components released by complete hydrolysis of non-starch polysaccharides of feed ingredients of vegetable origin. Two studies were conducted to investigate the apparent ileal digestibility and urinary excretion ofl-arabinose at dietary inclusion levels of 50 and 100 g/kg, and 25, 50, 75 and 100 g/kg respectively, in pigs. As a reference, d-glucose was included in the studies. Water intake, ileal flow of volatile fatty acids and ileal and faecal digestibilities of dietary nutrients in pigs fed on the different diets were also examined. Castrated pigs were prepared with a post-valvularT-caecum cannula to measure ileal digestibility. Faecal digestibility was measured in non-cannulated pigs. Apparent ileal digestibility ofl-arabinose was found to be approximately 70%. The presence ofl-arabinose in the diet increased ileal flow of volatile fatty acids and lactic acid, suggesting the occurrence of microbial degradation ofl-arabinose in the pig small intestine.l-arabinose was partly excreted in the urine. The extent of this urinary excretion as a percentage of intake increased linearly (P < 0.01) as the dietary level increased. In pigs fed on the 25 gl-arabinose/kg diet, 10.9% of thel-arabinose consumed appeared in the urine. This level was increased to 14.7% when pigs were fed on a diet containing 100 gl-arabinose/kg diet. Faecal digestibility and retention of nitrogen decreased significantly in pigs fed on thel-arabinose diets.