Ileal digestibility of amino acids for zero-tannin faba bean (Vicia faba L.) fed to broiler chicks.

An experiment was conducted to determine the apparent ileal digestibility (AID) of amino acids (AA) in zero-tannin faba beans (ZFB; Vicia faba L.) fed to broiler chicks. In total, 120 broiler chicks were divided into 24 groups of 5 birds that were balanced for BW and fed 1 of 3 diets in a completely randomized design (8 groups/diet) from d 14 to 21 of age. The diets were a soybean meal-cornstarch-based basal diet or the basal diet with soybean meal and cornstarch replaced by 50% of either conventional (tannin-containing) faba beans (CFB) or ZFB. The CFB were fed for comparison with ZFB. All of the 3 diets contained chromic oxide (0.3%) as an indigestible marker, and nutrient digestibilities were determined by the difference method. On d 21, the birds were killed by cervical dislocation and contents of the lower-half of the ileum were obtained for determination of apparent AA digestibility. The CFB and ZFB were similar in CP, AA, neutral detergent fiber, and acid detergent fiber contents. The ZFB did not contain tannins, whereas the CFB contained 0.82% tannins. The ZFB had greater (P < 0.05) AID for all AA (except Met) compared with that of the CFB by an average of 12.6 percentage points. The 2 faba-bean types were similar in AID of Met. The results show that the ZFB evaluated in the current study had greater AID of AA than CFB, and hence, it may be a better source of protein for broiler chicks than CFB.