EFFECT OF TANNINS ON STARCH DIGESTIBILITY AND TMEN OF TRITICALE AND SEMIPURIFIED STARCHES FROM TRITICALE AND FIELD BEANS

1. The effects of field bean tannin-containing hulls (T-hulls), non-ta nnin hulls (NT-hulls) and tannin extract on starch digestibilities and TMEn of triticale and semipurified starches from triticale and field beans were evaluated with adult cockerels and 3-week-old-chicks. 2. Fo r both cockerels and chicks, the digestibility and TMEn of semipurifie d starches from triticale were higher than those from beans. Starch di gestibilities of triticales (range 99.1 to 97.7%), of semipurified sta rches from triticales (range 96.5 to 89.9%) and from field beans (rang e 75.4 to 71.6%) were similar for both cockerels and chicks. 3. The ad dition of NT-hulls improved, in general, the digestibility of semipuri fied starches for both chicks and cockerels, which suggests that fibre improves the digestion of semipurified starches. 4. The effects of ta nnins of T-hulls on semipurified starch from beans and from triticale were different. Tannins always decreased the digestibility and TMEn of semipurified starch from field beans but only decreased the digestibi lity and TMEn of semipurified starch from triticale when fed to chicks , but not when fed to cockerels. 5. The addition of tannin extract alw ays decreased the digestibility of semipurified starches by a greater amount than T-hulls, which supports the idea that the effect of tannin s depends on the quantity of tannin ingested.