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Conserving purple prairie clover ( Dalea purpurea V ent.) as hay and silage had little effect on the efficacy of condensed tannins in modulating ruminal fermentation in vitro
Author(s) -
Peng Kai,
Xu Zhongjun,
Nair Jayakrishnan,
Jin Long,
McAllister Tim A,
Acharya Surya,
Wang Yuxi
Publication year - 2021
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.10913
Subject(s) - silage , hay , rumen , neutral detergent fiber , dry matter , fermentation , forage , incubation , proanthocyanidin , chemistry , biology , zoology , food science , agronomy , botany , biochemistry , polyphenol , antioxidant
Abstract BACKGROUND The objective of this study was to determine the effects of forage conservation method and condensed tannins (CT) in conserved forage on rumen fermentation. Purple prairie clover (PPC; Dalea purpurea Vent.) containing 84.5 g kg −1 dry matter (DM) of CT was harvested at full flower and preserved as freeze‐dried green chop (F), hay (H) or silage (S). Batch culture incubations were conducted using conserved forages as a substrate and treatments were arranged as 3 × 2 factorial design of forage type (F, H and S) with or without polyethylene glycol (PEG). PEG was used to isolate the effects of CT on fermentation. Incubation was repeated twice with quadruplicate vials for each treatment in each incubation. 15 N‐labelled ammonium sulfate was used as microbial N marker and headspace gas was sampled to determine methane production. RESULTS Concentrations of neutral detergent fiber (NDF) and acid detergent fiber were lower ( P < 0.01) in F than in H or S. Ensiling decreased ( P < 0.001) total phenolics and extractable CT, but had no effect on total CT, whereas none of these phenolic fractions were altered in H. Hay and silage had lower ( P < 0.01) true DM disappearance (TDMD) and NDF disappearance (NDFD) than F. Inclusion of PEG did not affect TDMD or NDFD after 8, 24 or 72 h of incubation. Productions of total gas, methane and total volatile fatty acid and the rate of gas production ( c ) were also similar, but ammonia was higher ( P < 0.05) and microbial N was lower ( P < 0.05) with than without PEG after 72 h of incubation. After 72 h, a lower ( P < 0.001) proportion of acetate but higher ( P < 0.05) proportion of propionate was noted with S, resulting in a lower ( P < 0.001) acetate:propionate ratio as compared to F or H after 8 h of incubation. CONCLUSION Condensed tannins in PPC decreased protein degradation in vitro , but had minimal effects on overall rumen fermentation, and conservation of PPC as hay or silage had little effect on the efficacy of CT in modulating rumen fermentation. © 2020 Her Majesty the Queen in Right of Canada. Journal of The Science of Food and Agriculture © 2020 Society of Chemical Industry.