In vitro rumen fermentation characteristics of bakery by‐products containing high starch and sugar

Abstract

The objectives of this study were to evaluate the nutritional characteristics of bakery by‐products (castella, pancake, baumkuchen) and their effect on rumen fermentation in vitro as compared with steam‐flaked corn and barley as human‐edible grains. The fermentation pattern of sugar and starch as pure components was also investigated. Additionally, rumen pH was evaluated using a low‐capacity buffer. Bakery by‐products contained high sugar (212–590 g/kg DM) and starch (262–545 g/kg DM). Castella exhibited the highest sugar content, whereas pancake and baumkuchen were rich in starch and ether extract within bakery by‐products, respectively. The gas production rate at the early phase of incubation was higher in bakery by‐products than in grains, and the highest in castella among all feeds. Bakery by‐products produced higher total organic acids and propionate than grains. Bakery by‐products also exhibited a lower rumen pH than grains during twenty‐four hours of incubation with a low‐capacity buffer. As pure components, sucrose showed a higher gas production rate and lower pH than starch. Overall, compared with grains, bakery by‐products have the potential not only to supply more energy to ruminants but also decrease rumen pH because sugar and starch in bakery by‐products ferment rapidly and produce higher organic acids in the rumen.