In vivo methods to study the digestion of starch in pigs and poultry

Starch is the largest constituent in diets for pigs and poultry. Pure starch consists predominantly of α-glucan in the form of amylose and amylopectin, embedded in a relatively hydrophobic protein network and surrounded by cell walls. The techniques most commonly employed when studying the quantitative and qualitative digestion of starch are: (1) the slaughter technique that involves slaughtering of animals at a given time point after a meal and collection of samples at various sites of the gastrointestinal tract, (2) the cannulation techniques that involve surgical implantation of one or more permanent cannulas in the gastrointestinal tract (stomach, small intestine and caecum), and (3) the catheterisation technique with surgical installation of permanent catheters in the portal vein and an artery. Results obtained in studies with pigs and poultry are used to discuss strengths and weaknesses of the different methodologies in gaining new insight into the digestion of starch in non-ruminant species.