Potential of tannin-rich plants for modulating ruminal microbes and ruminal fermentation in sheep1

Abstract

The objective of this work was to study nutritional strategies for decreasing methane production by ruminants fed tropical diets, combining in vitro and in vivo methods. The in vitro approach was used to evaluate the dose effect of condensed tannins (CT) contained in leaves of Gliricidia sepium, Leucaena leucocephala, and Manihot esculenta (39, 75, and 92 g CT/kg DM, respectively) on methane production and ruminal fermentation characteristics. Tannin-rich plants (TRP) were incubated for 24 h alone or mixed with a natural grassland hay based on Dichanthium spp. (control plant), so that proportions of TRP were 0, 0.25, 0.5, 0.75, and 1.0. Methane production, VFA concentration, and fermented OM decreased with increased proportions of TRP. Numerical differences on methane production and VFA concentration among TRP sources may be due to differences in their CT content, with greater effects for L. leucocephala and M. esculenta than for G. sepium. Independently of TRP, the response to increasing doses of CT was linear for methane production but quadratic for VFA concentration. As a result, at moderate tannin dose, methane decreased more than VFA. The in vivo trial was conducted to investigate the effect of TRP on different ruminal microbial populations. To this end, 8 rumen-cannulated sheep from 2 breeds (Texel and Blackbelly) were used in two 4 × 4 Latin square designs. Diets were fed ad libitum and were composed of the same feeds used for the in vitro trial: control plant alone or combined with pellets made from TRP leaves at 44% of the diet DM. Compared to TRP, concentration of Ruminococcus flavefaciens was greater for the control diet and concentration of Ruminococcus albus was least for the control diet. The methanogen population was greater for Texel than for Blackbelly. By contrast, TRP-containing diets did not affect protozoa or Fibrobacter succinogenes numbers. Hence, TRP showed potential for mitigating methane production by ruminants. These findings suggest that TRP fed as pellets could be used to decrease methane production.

Determination of Cell Wall Protein from Selected Feedstuffs and its Relationship with Ruminal Protein Digestibility in Vitro

“…Such high amounts of tannins were shown to be negatively correlated with total gas production and OMD (Jayanegara et al, 2011) since the compounds bind to protein and fiber present in feedstuffs through particularly hydrogen bonds (Jayanegara et al, 2009;. Similar explanation was also applied to gliricidia since the forage contains substantial amount of tannins (Cudjoe & Mlambo, 2014;Rira et al, 2015). Soybean meal showed the highest DMD and OMD over all other feedstuffs, indicating its superiority as a plant based protein concentrate.…”

Potential of tannin‐rich plants, Leucaena leucocephala, Glyricidia sepium and Manihot esculenta, to reduce enteric methane emissions in sheep

“…Fermentation and some microbial parameters were also measured at the end of each period, and results were published by Rira et al. (). Rams were tied in stalls throughout the experiment and had free access to water and salt block.…”

“…In a companion paper of this work by Rira et al. (), fermentation and microbial parameters were described.…”

Emisión de metano en ovinos alimentados con Pennisetum purpureum y árboles que contienen taninos condensados

“…En este estudio no se observaron cambios en la concentración total e individual de los AGV, resultados apoyados por Rira et al (27) quienes con la inclusión de 44 % de L. leucocephala, no observaron efectos sobre los AGV.…”