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Modification of in‐vitro digestibility and cell‐wall composition of cocksfoot, ryegrass and timothy by imazethapyr
Author(s) -
Fales Steven L,
Bohn Peter J,
Hoover Ronald J,
Karunanandaa Kanthasamy
Publication year - 1991
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740540109
Subject(s) - dactylis glomerata , lolium multiflorum , ferulic acid , lolium perenne , neutral detergent fiber , dry matter , composition (language) , phleum , chemistry , lignin , lolium , zoology , hemicellulose , poaceae , agronomy , biology , botany , food science , linguistics , philosophy
Recent studies have shown that the compound imazethapyr (5‐ethyl‐2‐(4‐isopropyl‐4‐methyl‐5‐oxo‐2‐imidazolin‐2‐yl)nicotinic acid) possesses growth regulatory activity and can be used to enhance nutritive value of grasses. However, little is known about possible effects of this material on fibre composition or potential fibre utilisation by ruminants. The objective of this research was to examine imazethapyr‐treated cocksfoot ( Dactylis glomerata L), ryegrass (Lolium perenne L × L multiflorum Lam), and timothy ( Phleum pratense L) for possible treatment‐induced changes in in‐vitro digestibility and in concentrations of selected fibre constituents. Replicated field plots treated with imazethapyr at 0 (control) or 100 g ai ha −1 during the vegetative (pre‐elongation) stage of growth were harvested when controls were in the early stage of inflorescence emergence. Samples taken from treated plots 4 weeks post‐treatment had higher in‐vitro dry matter disappearance (IVDMD), lower neutral detergent fibre (NDF), lower acid detergent fibre (ADF), lower cellulose, lignin, and higher hemicellulose concentrations compared with controls. Imazethapyr treatment also reduced the concentration of p ‐coumaric acid in NDF, but had no effect on ferulic acid. The treatment effect on in‐vitro NDF disappearance, however, was inconsistent among the grass species and was statistically non‐significant ( P = 0·10), implying that, under the conditions of this study, imazethapyr‐related enhancements in IVDMD can be attributed primarily to a reduction in the amount of NDF and its associated constituents, as opposed to qualitative differences in NDF composition.