This study evaluated the effect of high or low digestible energy ratio of
carbohydrate in a high or normal dietary energy density on performance,
amino acid utilization and intestinal functions of weaned piglets. A total of 32 healthy weaners (9.60 ± 0.13 kg) were allocated to two dietary energy densities (3,400 and 3,800 kcal/kg) and two digestible energy ratio of
carbohydrate to fat (9:1 and 3:1) in a 2 × 2 factorial arrangement. There were eight piglets per treatment. The feed intake of piglets was significantly increased by dietary high
carbohydrate ratio (9:1) (p < 0.01); however, this did not result in improved
body weight gain (p > 0.05). The piglets fed high
carbohydrate energy ratio had a reduced villus height/crypt depth (VH/CD) ratio in the duodenum (p < 0.05), and dietary high energy density further decreased the VH/CD ratio in the ileum (p < 0.01). In the duodenum, the lymphocyte count was increased by dietary high energy density (p < 0.05), while dietary energy density and
carbohydrate energy ratio interacted to increase lymphocyte count in the ileum (p < 0.05). The serum
cholesterol,
triglyceride and
low-density lipoprotein were not significantly affected (p > 0.05), but dietary energy density interacted with dietary energy ratio to increase
high-density lipoprotein concentration (p < 0.05) in piglets fed reduced
carbohydrate energy ratio. Dietary high energy density reduced energy digestibility (p < 0.05), whereas high
carbohydrate energy ratio increased crude
protein digestibility in the piglets (p < 0.05). The intestinal
sucrase,
lactase activities and serum concentrations of
histidine,
leucine,
lysine,
methionine,
phenylalanine,
alanine,
glycine,
tyrosine and
citrulline were higher in the piglets fed dietary increased
carbohydrate energy ratio. Oxidative stress markers and
volatile fatty acids concentrations were altered by the dietary treatments. It was concluded that dietary high energy density could be detrimental to piglets intestinal functions and that increased
carbohydrate energy ratio could affect
amino acid utilization and
body weight gain in weaner pigs.