Gastrointestinal tract development in fattening lambs fed diets with different amylose to amylopectin ratios

Thirty-six, 7-d-old male lambs of similar weights were used in the current study to examine the effects of dietary amylose to amylopectin ratios (amylose/amylopectin) on gastrointestinal development in fattening lambs fed concentrates with different sources of starch (tapioca, wheat, maize, and pea) and amylose/amylopectin (0.12, 0.23, 0.24, and 0.48, respectively). The maize starch (MS) and wheat starch (WS) diets improved weight and volume of gastrointestinal. The pea starch diet significantly increased papillar height (P < 0.001), papillar surface area (P = 0.019), and density of papillae (P = 0.001) in the rumen. Additionally, the pea starch diet significantly enhanced villus height, crypt depth, and villus surface area and villus/crypt ratio (P < 0.05) in small intestine. Expressions of insulin-like growth factors I (IGF-1) and insulin-like growth factors’ receptors (IGF-1R) significantly increased in the duodenum mucosa (P = 0.021, P = 0.006, respectively), jejunum mucosa (P = 0.002, P = 0.005, resp...