Hulless barley (Hordeum vulgare l.) with altered starch traits: rumen degradation kinetics
Date
2012-03-13
Authors
Yang, L.
McKinnon, J.J.
Christensen, D.
Rossnagel, B.
Beattie, A.
Yu, P.
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ORCID
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Poster Presentation
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Abstract
The objective of this study was to determine the effect of new hulless barley lines
(zero-amylose waxy, CDC Fibar; 5%-amylose waxy, CDC Rattan; normal-amylose, CDC
McGwire and high-amylose, HB08302) on rumen degradation kinetics and in vitro intestinal
nutrient digestion with CDC Copeland included as a hulled control. Three dry Holstein cows
fitted with rumen cannula were used for measuring rumen degradation of barley varieties. The
estimation of intestinal digestion was determined by a modification of the three-step in vitro
procedure described by Calsamiglia and Stern with duplicate of each in situ residue. Among
the hulless barley lines, CDC Rattan was greater (P<0.05) in effectively degradable starch
(EDST: 461 g/kg DM) but reduced (P<0.05) in rumen undegradable protein (RUP: 55g/kg
DM) while CDC Fibar was greater (P<0.05) in effectively degradable crude protein (EDCP:
90 g/kg DM) and total digestible protein (TDP: 147 g/kg DM) than other hulless barley lines.
CDC McGwire showed greater (P<0.05) in total digestible bypass starch (TDST: 590 g/kg
DM), effectively degradable CHO (EDCHO: 581 g/kg DM) and total digestible CHO
(TDCHO: 600 g/kg DM) than other hulless barley lines but no significant difference
compared to CDC Copeland (P>0.05). HB08302 was greater (P<0.05) in rumen bypass starch
(BST: 218 g/kg DM vs. 146 g/kg DM and 155 g/kg DM) and effective degradable NDF
(EDNDF: 74 g/kg DM vs. 49 g/kg DM and 52 g/kg DM) than CDC Fibar and CDC Rattan.
HB08302 was also greater in total digestible NDF (TDNDF: 93 g/kg DM vs. 62 g/kg DM and
67 g/kg DM) and intestinal digestible rumen bypass starch (IDBST: 180 g/kg DM vs. 122
g/kg DM and 130 g/kg DM) compared to CDC Fibar and CDC McGwire. HB08302 also
showed greater (P<0.05) in bypass CHO (BCHO: 179 g/kg DM) and intestinal digestible
bypass CHO (IDBCHO: 31 g/kg DM) than other hulless barley lines. Amylose and
amylopectin were significantly correlated (P<0.001) to EDCP (r=-0.71, r=0.64) and TDP
(r=-0.85; r=0.77), while amylose, ratio of amylose and amylopectin were positively correlated
(P<0.01) to EDNDF, TDNDF, BST, IDBST and TDCHO (P<0.05). BCP, IDP, TDP, BNDF
were positively correlated to beta-glucan levels (P<0.001) while EDST, TDST, EDCHO and
TDCHO were negatively correlated to beta-glucan levels in hulless barley lines (P<0.01). in
conclusion hulless barley lines with altered carbohydrate traits have the potential to increase
rumen and intestinal nutrient availability to ruminants. Altered beta-glucan levels had a
greater effect on rumen carbohydrates and crude protein degradation than altered starch traits.
Description
Keywords
amylose and amylopectin ratio, beta-glucan, intestinal digestion
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Part Of
Soils and Crops Workshop