Nutrient Infusion into the Ileum of Rats Does Not Lower Plasma Lipids or Alter Apolipoprotein mRNA Abundance

Abstract

Viscous polysaccharides enhance the delivery of nutrients to the ileum. Our objective was to determine if the presence of nutrients in the ileum, in the absence of fiber, alters plasma and hepatic lipids. Twenty-four wistar male rats weighing 150–160 g were fed a fiber-free purified diet (30% of energy as fat) for 7 d. The small intestine was cannulated 30 cm proximal to the ileo-cecal junction. The animals consumed the purified diet ad libitum and the intestine was infused (3 mL/h) with saline, or an enteral solution contributing 10, 20 or 30% total energy for half of a 12-h feeding period. Infusion was performed for 14 d, after which the animals were killed. The animals adjusted their food intake so that each group had an equivalent energy intake and weight gain over the experimental period. The relative ileal mucosa weight was increased with nutrient infusion indicating hypertrophy. Plasma cholesterol in the nutrient-infused animals tended to be higher than in the saline-infused animals (P < 0.06). Apolipoprotein B and A-IV mRNA were not affected by ileal infusion. Thus, enhanced delivery of nutrients to the ileum, without fiber present in the diet, does not lower plasma cholesterol.