title: Effects of Aspergillus Oryzae Culture and 2-Hydroxy-4-(Methylthio)-Butanoic Acid on In vitro Rumen Fermentation and Microbial Populations between Different Roughage Sources.
abstract: An in vitro experiment was conducted to evaluate the effects of Aspergillus oryzae culture (AOC) and 2-hydroxy-4-(methylthio)-butanoic acid (HMB) on rumen fermentation and microbial populations between different roughage sources. Two roughage sources (Chinese wild rye [CWR] vs corn silage [CS]) were assigned in a 2×3 factorial arrangement with HMB (0 or 15 mg) and AOC (0, 3, or 6 mg). Gas production (GP), microbial protein (MCP) and total volatile fatty acid (VFA) were increased in response to addition of HMB and AOC (p<0.01) for the two roughages. The HMB and AOC showed inconsistent effects on ammonia-N with different substrates. For CWR, neither HMB nor AOC had significant effect on molar proportion of individual VFA. For CS, acetate was increased (p = 0.02) and butyrate was decreased (p<0.01) by adding HMB and AOC. Increase of propionate was only occurred with AOC (p<0.01). Populations of protozoa (p≤0.03) and fungi (p≤0.02) of CWR were differently influenced by HMB and AOC. Percentages of F. succinogenes, R. albus, and R. flavefaciens (p<0.01) increased when AOC was added to CWR. For CS, HMB decreased the protozoa population (p = 0.01) and increased the populations of F. succinogenes and R. albus (p≤0.03). Populations of fungi, F. succinogenes (p = 0.02) and R. flavefacien (p = 0.03) were increased by adding AOC. The HMB×AOC interactions were noted in MCP, fungi and R. flavefacien for CWR and GP, ammonia-N, MCP, total VFA, propionate, acetate/propionate (A/P) and R. albus for CS. It is inferred that addition of HMB and AOC could influence rumen fermentation of forages by increasing the number of rumen microbes.
authors.affiliation: Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China ; Qilu University of Technology, Jinan, 250353, China .
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.affiliation: Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Y M
authors.initials: YM
authors.lastname: Wu
authors.affiliation: Novus International Research Center, Beijing, 100085, China .
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
authors.affiliation: Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
authors.forename: J X
authors.initials: JX
authors.lastname: Liu
authors.affiliation: Department of Animal Science, Chonnam National University, Gwangju 500-757, Korea .
authors.forename: K H
authors.initials: KH
authors.lastname: Myung
keywords: 2-Hydroxy-4-(Methylthio)-Butanoic Acid; Aspergillus Oryzae; Chinese Wild Rye; Corn Silage; In vitro Rumen Fermentation; Microbial Population