Search

A study was conducted to determine how total phenolic (TP), protein precipitable phenolic (PPP), C, and N concentrations, and amount of protein bound (PB) by PPP in leaves of Desmodium paniculatum (panicled tick-clover; PTC) and Lespedeza cuneata (sericea lespedeza; SL) were affected by simulated herbivory and plant ontogeny. All PTC treatments resulted in a decrease (P ≤ 0.05) in TP, PPP, C, and N concentrations and PB between vegetative and seed set stages. All SL treatments resulted in increased (P ≤ 0.05) or stable TP and PPP concentrations from vegetative stage to seed set. The amount of PB was greatest (P ≤ 0.05) in SL plants submitted to 25% defoliation, and flowering and seed set stages had greater (P ≤ 0.05) PB than the vegetative stage. Ontogenesis and defoliation did not (P > 0.05) affect SL N and C concentrations. The protein binding characteristics of PPP from PTC, but not that of SL, appear to be altered in response to stress. Results might correspond with seed dispersal strategies of the two species, with PTC's epizoochory making increased palatability at seed set beneficial. [ABSTRACT FROM AUTHOR]

The beneficial effects of forages containing condensed tannins (CTs) on ruminants are well documented, but the chemical features of CT that yield benefits have not been defined. Some evaluations of limited numbers of highly purified compounds have resulted in positive correlations between CT molecular weight (MW) and biological activity, while others have failed to show a correlation. The objectives of this study were to determine if MW of CT could predict biological activity relative to protein precipitability. MW of condensed tannin, proteinprecipitable phenolics (PPP), and the amount of protein bound (PB) were determined for nine species of warmseason perennial legumes. There was no correlation between PPP or PB and MW (R² 0.11 and R² 0.02, respectively). However, CT concentration did correlate with PPP and PB (R² 0.81 and R² 0.69, respectively). It was concluded that CT MW does not explain the variation in protein precipitation by CT from the forage legumes surveyed. [ABSTRACT FROM AUTHOR]