In Vitro Rumen Fermentation Studies with a Bird Resistant Sorghum Grain

Abstract

IN VITRO rumen fermentations were made with Arkansas (AKS) 614 (bird resistant sorghum grain to measure the effects of processing on these grains. Differences among and within grains were measured as milliliters of gas produced per gram of dry matter incubated and in vitro dry matter disappearance. Dry ground AKS 614 sorghum grain consistently produced less gas than a similarly treated non-bird resistant hybrid. However, when these grains were steam processed and flaked, the differences in gas production were less. Tannic acid addition to both nonprocessed and processed AKS 614 and red grain significantly depressed gas production and dry matter disappearance but this effect was not as large when the additions were made to steam processed flaked grains. A larger percentage of the isolated tannic acid was necessary to depress gas production than could be accounted for by the tannic acid content of the AKS 614 grain; thus, it would appear that tannic acid alone cannot account for the decreased utilization of AKS 614 sorghum grain unless the naturally occurring tannins have the ability to act in much lower concentrations than isolated tannic acid. Pearling AKS 614 did not significantly change gas production from that of the nonpearled grain; however, gas production was reduced when AKS 614 pericarp was added to AKS 614 or red pearled grain steam processed by the laboratory method. This depression in gas production was not evident when the AKS 614 pericarp was added to the pearled, nonprocessed grains. When the red grain pericarp was added to the two grains, gas production was enhanced