APPARENT, TRUE AND REAL ILEAL PROTEIN AND AMINO-ACID DIGESTIBILITIES IN GROWING PIGS FED 2 VARIETIES OF FABABEANS (VICIA-FABA L) DIFFERENT IN TANNIN CONTENT

Five gilts, with an average initial BW of 35 kg, were fitted with a si mple T-cannula at the distal ileum and with two catheters in the exter nal jugular veins. The pigs were fed twice daily 700 g of two semi-pur ified corn starch-based diets that contained 30% of white- or dark-flo wered fababeans (Vicia faba L.), with .1 and .58% condensed tannins, r espectively. Chromic oxide was included to determine nutrient digestib ilities. N-15-leucine was infused continuously via a jugular catheter for 9 d (160 mg of N-15-leucine per d and animal). Ileal digesta were collected for 24 h on d 7 and 9 of the infusion period. Blood samples were taken every 6 h during digesta collections. The contribution of e ndogenous to total protein and amino acids was calculated according to the principles of the N-15-isotope dilution technique. The real ileal protein and amino acid digestibilities were considerably higher than their corresponding apparent values e. g., for protein the differences were 17.1 and 19.3 percentage units for the white- and dark-coloured beans, respectively. These differences are related to the recovery of protein and amino acids of endogenous origin in the small intestine. H owever, it appears that a difference in condensed tannin content of ap proximately 0.2% as reported in this study has only a small effect on the ileal recovery of protein and amino acids. This conclusion may not be valid if there had been a larger difference in tannin content, as was evident from the studies that were reviewed.