Digesta collection procedure may affect ileal digestibility in pigs fed diets based on wheat bran or beet pulp

Abstract

Digestibility determined by collection of feed residues at the terminal ileum (ileal digestibility) has been shown to provide a reliable estimate of amino acid availability to the pig. As a routine technique to collect ileal digesta, an ileo-rectal anastomosis (IRA) has been proposed. In this trial, four Large White pigs (52.0 ± 1.5 kg) were used to test IRA against ileo-colic post-valve fistulation (ICPV), considered as a reference fistulation technique. A standard cereal-based diet and two semi-synthetic diets enriched with either wheat bran or beet pulp were used. They were given consecutively to each group of two pigs (ICPV, IRA), once or twice a day, in the order mentioned above. Similar values for total nitrogen and amino acid-digestibility were obtained in ICPV and IRA pigs on the standard or the wheat bran diets. On the beet pulp diet, ICPV collection resulted in a significantly higher apparent digestibility of total nitrogen and amino acids than did IRA collection. This was probably due to the bypass of the ileo-caeco-colic sphincter in the IRA pigs. Therefore, depending on the diet, digestibility values based on IRA collection may differ from those measured by ICPV collection. Further work is needed to identify the particular conditions that make ileo-caeco-colic sphincter function a critical determinant of digestibility values.