Effect of starch type, total β-glucans and acid detergent fiber levels on the energy content of barley (Hordeum vulgare L.) for poultry and swine

Effects of starch type, total beta-glucans and ADF levels on DMD, nitrogen-corrected TME for poultry and DE for swine were evaluated in four experiments utilizing synthetic barley mixtures produced by differential pearling and milling. Forty-seven mature roosters were used in exp. 1 and 45 were used in exp. 3 to determine DMD and TME for poultry and 3 duodenally cannulated pigs were used in exps. 2 and 4 to determine DMD and DB for swine utilizing the MNBT. In exps. 1 and 2, synthetic barley (normal starch) with 11.0% ADF contained lower TME (2733 kcal kg(-1)) and DE (3278 kcal kg(-1)) compared to barley with 3.5% ADF (3371 and 3943 kcal kg(-1), respectively). Increasing total beta-glucans from 3.4 to 6.8% decreased TME from 3248 to 2855 kcal kg(-1) and DE from 3679 to 3542 kcal kg(-1). In exps. 3 and 4, there was an interaction between ADF and starch type. With normal starch, increasing ADF from 2.1 to 12.0% reduced TME from 3301 to 2630 kcal kg(-1) and DE from 4018 to 3247 kcal kg(-1) but with waxy starch, increasing ADF had no effect on either TME (2996 vs. 3086 kcal kg(-1)) or DE (3918 vs. 3712 kcal kg(-1)). These data suggest that the energy content of barley for poultry and swine is decreased greatly by high ADF and less by high total beta-glucans, that beta-glucans have a larger negative effect on energy for poultry than for swine, but that high ADF has a minimal effect on energy when barley starch is waxy regardless of the level of beta-glucans. The negative effects of high beta-glucans from waxy barley in exps. 3 and 4 were more apparent when the diets were low in ADF.