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

Abstract

Effects of starch type, total β-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 DE 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 β-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 β-glucans, that β-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 β-glucans. The negative effects of high β-glucans from waxy barley in exps. 3 and 4 were more apparent when the diets were low in ADF. Key words: Barley, fiber, energy, digestibility, β-glucans