To evaluate the effects of dietary hemicellulose from corn on growth and metabolic measures, female pigs (n = 48; initial BW 30.8 kg) were fed diets containing 0 to 38.6% solvent-extracted corn germ meal for 28 d. Increasing the hemicellulose level had no impact on ADG or ADFI, but resulted in a quadratic response on G:F. To investigate physiological changes that occur with increased dietary hemicellulose, blood, colon contents, and tissue samples from the liver and intestine were obtained from a subset (n = 16; 8 pigs/treatment) of pigs fed the least and greatest hemicellulose levels. The abundance of phosphoadenosine monophosphate-activated protein kinase (AMPK) and the mitochondrial respiratory protein, cytochrome C oxidase II (COXII) were determined in liver, jejunum, ileum, and colon by Western blotting. The mRNA expression levels of AMPKα1, AMPKα2, PPAR coactivator 1α (PGC1-α), PPARγ2, and sirtuin 1 (Sirt1) were determined in liver and intestinal tissues. When compared with pigs fed the control diet, pigs fed the high hemicellulose diet had increased plasma triglycerides, but there was no difference in plasma cholesterol, glucose, or insulin. Absolute and relative liver weights were decreased in pigs consuming the high hemicellulose diet. The highfiber diet led to a tendency for decreased liver triglyceride content. In pigs fed the high hemicellulose diet, ileal mucosal alkaline phosphatase activity was increased and sucrase activity tended to be increased. The high hemicellulose diet had no effect on phospho-AMPK, AMPK mRNA, or colonic VFA, but in pigs consuming the high fiber diet there was a greater abundance of COXII in colon tissue. The expression of PGC1-α, PPARγ, or Sirt1 mRNA was not altered by dietary fiber in liver, jejunum, or ileum tissue. In colon tissue from pigs fed the high fiber diet there was an increase in Sirt1 mRNA and a trend toward increased of PGC1-α mRNA. These data suggest that alterations in metabolism involved in adaptation to a diet high in hemicellulose are associated with increased colonic Sirt1 mRNA and COXII expression, indicating an increased propensity for oxidative metabolism by the intestine.

For more information the full article can be found at http://jas.fass.org/