Fermentation of Ammonia Fiber Expansion Treated and Untreated Barley Straw in a Rumen Simulation Technique Using Rumen Inoculum from Cattle with Slow versus Fast Rate of Fiber Disappearance

Abstract

The purpose of this study was to determine the effect of rumen inoculum from heifers with fast vs. slow rate of in situ fiber digestion on the fermentation of complex versus easily digested fiber sources in the forms of untreated and Ammonia Fiber Expansion (AFEX) treated barley straw, respectively, using an artificial rumen simulation technique (Rusitec). In situ fiber digestion was measured in a previous study by incubating untreated barley straw in the rumen of 16 heifers fed a diet consisting of 700 g/kg barley straw and 300 g/kg concentrate. The two heifers with fastest rate of digestion (Fast ≥ 4.18% h-1) and the two heifers with the slowest rate of digestion (Slow ≤ 3.17% h-1) were chosen as inoculum donors for this study. Two Rusitec apparatuses each equipped with eight fermenters were used in a completely randomized block design with two blocks (apparatus) and four treatments in a 2 × 2 factorial arrangement of treatments (Fast or Slow rumen inoculum and untreated or AFEX treated straw). Fast rumen inoculum and AFEX straw both increased (P < 0.05) disappearance of dry matter (DMD), organic matter, true DMD, neutral detergent fiber, acid detergent fiber, and nitrogen (N) with an interactive effect between the two (P < 0.05). Fast rumen inoculum increased (P > 0.05) methane production per gram of digested material for both untreated and AFEX straw, and reduced (interaction, P < 0.05) acetate: propionate ratio for untreated straw. Greater relative populations of Ruminococcus albus (P < 0.05) and increased microbial N production (P = 0.045) were observed in Fast rumen inoculum. AFEX straw in Fast inoculum had greater total bacterial populations than Slow, but for untreated straw this result was reversed (interaction, P = 0.013). These findings indicate that differences in microbial populations in rumen fluid contribute to differences in the capacity of rumen inoculum to digest fiber.

Screening of white‐rot fungi for bioprocessing of wheat straw into ruminant feed

“…The effect of a change from complex to easily digestible fibre sources (by means of chemical pretreatment) on the VFA production has been demonstrated by Griffith et al . (). They reported a similar decrease in acetate and acetate/propionate ratio, as well as an increase in propionate molar proportion.…”

Symposium review: Technologies for improving fiber utilization

“…Similarly, AFEX treatment increased IVNDFD of corn stover and wheat straw by 19 to 20% (Bals et al, 2010). Recently, Griffith et al (2016) reported 35 and 27% greater in vitro dry matter digestibility (IVDMD) and IVNDFD due to AFEX treatment of barley straw. Feeding trials with lactating dairy cows using AFEX-treated rice straw have shown adequate intake and no adverse health effects with the treated material (Weimer et al, 2003;Blummel et al, 2014).…”

“…An alternative to direct ammoniation alone that combines chemical and physical treatments is AFEX. The method involves ammoniating low-quality forages at high temperature and pressure, with subsequent pressure release and ammonia removal (Campbell et al, 2013;Griffith et al, 2016) or recycling. Bals et al (2010) observed 206% greater NDFD with AFEX treatment of late harvest switch grass relative to the untreated forage versus 56% greater digestibility with traditional ammoniation.…”

“…Nevertheless, research on the effects and fate of residual acetamide in cattle fed AFEX-treated forages are needed to ensure that meat and milk are not contaminated. Recent animal trials have not reported adverse health effects (Blummel et al, 2014;Griffith et al, 2016;Mor et al, 2018). The main advantages of AFEX treatment over traditional ammoniation method include safety, as the pellets generated are benign, ease of transport due to density of the pellets, and recycling of the ammonia.…”

Synchrony Degree of Dietary Energy and Nitrogen Release Influences Microbial Community, Fermentation, and Protein Synthesis in a Rumen Simulation System

“…Effluent was collected every day from days 6 to 8 in a 1.0-L container immersed in an ice water bath and filtered through a nylon cloth (Guangda Hengyi Co., Beijing, China) with an inner size of 8 cm × 12 cm and a pore size of 40 µm, as described in previous studies [15,31]. The residues were used to determine DM, organic matter (OM), NDF and CP as described in other studies [32,33], and filtrate was used to detect MPS.…”