Digestion of starch and fibre carbohydrates in peas by adult cockerels

Abstract

The digestion of starch and fibre by adult cockerels fed peas which were whole, ground, autoclaved, heated, dehulled, cooked or supplemented with a cellulose degrading enzyme was studied. The starch in ground peas that had been autoclaved, heated or dehulled was slightly, though not significantly, better digested than the starch in peas that had been ground only. Feeding peas whole greatly reduced starch digestibility. Cooking failed to improve starch digestibility as retrograded starch produced in the cooking process was not digested. The more finely ground the foodstuff, the better the in vitro enzymatic hydrolysis of starch. Starch digestibility correlated well (r2 = 0.80) with the true metabolisable energy values obtained for the different pea treatments. In experiment 1 cockerels digested on average 0.22 of the pea fibre from the different forms of peas. A significant decrease in xylose digestion was observed when birds were fed dehulled peas, birds excreting more xylose than they ingested. In experiment 2, cockerels digested on average 0.38 of the pea fibre from different forms of peas. A reduction in fibre digestion was observed when birds were fed cooked peas as a consequence of a decreased digestibility of all monosaccharide residues. A slight increase in fibre digestion was observed when peas were augmented with 'cellulase', entirely because of an increase in xylose digestion.