The effect of condensed tannins inLotus pedunculatuson the solubilization and degradation of ribulose-1,5-bisphosphate carboxylase (EC4.1.1.39; Rubisco) protein in the rumen and the sites of Rubisco digestion

Abstract

Three experiments were undertaken to determine the effect of condensed tannin (CT) in Lotus pedunculutus (45-55 g extractable CT/kg DM) on the digestion of the principal leaf protein, ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39; Rubisco; fraction 1 leaf protein). In two of the experiments Lotus pedunculutus was fed to sheep, with one group receiving a continuous intraruminal infusion (per fistulum) of PEG (molecular weight 3500) to bind and inactivate the CT (PEG group). The other group, which did not receive PEG, was termed the control sheep (CT acting). Expt 3 involved in vitvo incubations of Lotus pedunculutus in buffered rumen fluid, with and without PEG added. In all experiments the results have been interpreted in terms of the effects of CT on Rubisco solubTzation and degradation. Disappearance of N and Rubisco from Lotus pedunculutus suspended in polyester bags in the rumen was used as a measure of solubilization. Degradation was defined as the disappearance of Rubisco from in vitro incubations of Lotus pedunculatus in rumen fluid. In Expt 1, CT reduced the digestion of Rubisco in the rumen from 0.96 to 0.72 of intake (P c 0.01). Rubisco digestion in the small intestine was 0.27 of intake in control sheep and 0.04 of intake in PEG sheep. In Expt 2, PEG had no effect on the loss of Rubisco from Lotus pehneulatus contained in polyester bags which were incubated in the rumen, hence CT did not affect the solubilization of Rubisco. Observations in Expt 1 were confirmed by in vitro incubations in Expt 3, where PEG addition substantially increased the rate of degradation of plant protein to NH,. Addition of PEG decreased the period of time taken to degrade 50% of the Rubisco from about 13.8 h to about 3.0 h. It was concluded that the action of CT reduced the digestion of Rubisco in the rumen of sheep fed on fresh Lotus pedunculutus, and that this was primarily due to the ability of CT to slow its degradation by rumen micro-organisms, without affecting its solubilization. Both fresh-minced, and freeze-dried and ground lotus were used for in smco and in vitro incubations; however, fresh-minced lotus was more suitable for the evaluation of protein solubilization and degradation in fresh forages.Condensed tannin : Rnmen degradation: Ribulose-1,5-bisphosphate carboxylase When ruminants fed on fresh forage were given abomasal infusions of protein or fed on protein protected from rumen degradation, production responses included increased wool growth (Reis, 1979), milk production in dairy cattle (Rogers et al. 1980;Hamilton et al. 1992) and sheep (Penning et al. 1988), and live-weight gain (Barry, 1981;Stock et al. 1981 ;Hogan, 1982; Poppi et al. 1988;Fraser et al. 1990). These results suggest that productivity is reduced because insufficient essential amino acids (EAA) are absorbed from the small intestine relative to energy. The low absorption of amino acids (AA) is due in part to the

Potential use of Acacia mearnsii condensed tannins to reduce methane emissions and nitrogen excretion from grazing dairy cows

“…Condensed tannins can reduce apparent N digestibility of feed (McNabb et al 1996;Priolo et al 2000;Waghorn 2008) as was observed in the metabolism study where N digestibility decreased from 71 to 59% for Tannin 1 and to 50% for Tannin 2. Similarly, Carulla et al (2005) showed A. mearnsii CT offered at 25 g kg (1 DMI to sheep fed haylage (Â70% DM) reduced CP digestibility from 73 to 65%.…”

Meat odour and flavour and indoles concentration in ruminal fluid and adipose tissue of lambs fed green herbage or concentrates with or without tannins

“…Tannins have been extensively studied for their positive (McNabb et al, 1996) or negative (Priolo et al, 2000) effects on ruminant performance. In the last years, tannins have also been studied for their effects on ruminant meat quality (for a review see Priolo and Vasta, 2007).…”

The role of condensed tannins in ruminant animal production: advances, limitations and future directions

“…The effects of CT from various forage legumes on RDP are well studied, but the relationship is blurred by inconsistent experimental methodologies. In general, inclusion of dietary CT shifts the site of N metabolism and absorption by reducing both the rate and extent of ruminal protein degradation (Coblentz and Grabber, 2013) and NH 3 concentrations (McNabb et al, 1996;Min et al, 2005;Agle et al, 2010), increasing postruminal amino acid flow (Waghorn et al, 1994b). Results from our research team (Naumann et al, 2014c) suggested that we can use a screening tool to predict the potential of structurally diverse mixtures of CT to bind protein based on the concentration of protein-precipitable polyphenols ( Figure 5).…”