Effects of quebracho tannin extract on rumen fermentation and yield and composition of microbial mass in heifers1

Abstract

To determine the effects of incremental quebracho tannin extract (QTE) infusions on rumen fermentation and yield and composition of microbial mass, a study was conducted that consisted of 1 control period (Control I) without QTE dosing; 4 periods when all animals received 1, 2, 4, or 6% QTE of the diet (DM basis); and a second control period (Control II). Each period consisted of 9 d of adaptation, 6 d of urine collection, and 1 d of rumen sampling. Three rumen-fistulated heifers (495 kg BW [SE 14]) were offered 2.6 kg/d grass hay, 2.6 kg/d concentrates, and 60 g/d mineral-vitamin premix (as fed) in 2 equal meals. Half the daily QTE dosage was intraruminally administered at every meal. Urine and rumen fluids were analyzed for purine derivatives and short-chain fatty acids, respectively. Nitrogen and purine base (PB) concentrations were determined in liquid-associated microbes in rumen fluid (LAMF), liquid-associated microbes in the solid phase (LAMS), and particle-associated microbes (PAM). Increasing QTE dosages linearly increased propionate and butyrate proportions in rumen fluid ( = 0.37, = 0.004 and = 0.51, < 0.001, respectively). Instead, proportions of acetate ( = 0.75, < 0.001), isobutyrate ( = 0.66, < 0.001), and isovalerate ( = 0.49, < 0.001) and urinary purine derivatives excretions ( = 0.66, < 0.001) linearly decreased with increasing QTE infusions. Inconsistent differences were observed for LAMF, but concentrations of PB in LAMS ( ≤ 0.018) and of N in PAM ( < 0.001) were greater at 6% QTE than at Control I, II, and 1% QTE. Hence, low to moderate QTE dosages hamper rumen fermentation and microbial biomass yields. Alongside the nutritional consequences for the host, the methodological implications of these effects should be considered in studies evaluating the targeted use of tannins in ruminant feeding.

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

“…Higher CT concentrations in vivo decreased rumen NH 3 concentration up to 24% when L. corniculatus silage (7.3-9.5% dietary total CT) replaced M. sativa silage (0% dietary total CT) in a dairy cattle ration (Hymes-Fecht et al, 2013). A few studies however, have reported no effect of CT on ruminal NH 3 -N concentrations Dickhoefer et al, 2016). These results may be explained by CT source, lower water intake [i.e.…”

“…These results may be explained by CT source, lower water intake [i.e. lower NH 3 dilution as in Dickhoefer et al (2016)] or because energy availability was limiting for microbial growth. Christensen et al (2015) also reported no differences in rumen NH 3 -N concentration of lactating dairy cows after replacing 50 or 100% of M. sativa hay with L. corniculatus (0.51% CT).…”

“…Addition of QTE at 1, 2, and 3% of DM was reported to improve microbial efficiency in sheep fed M. sativa hay (Al-Dobaib, 2009) and Getachew et al (2008) reported improvements only at concentrations of 0.5 and 1%, but not 1.5%. In contrast, QTE infusion at 2, 4, or 6% of DM intake reduced duodenal microbial protein flow by 11, 21, and 39% (Dickhoefer et al, 2016) and up to 36% when QTE was supplemented at concentrations greater than 1% of DM intake (Ahnert et al, 2015).…”

Effect of tannins and monensin on feeding behaviour, feed intake, digestive parameters and microbial efficiency of nellore cows

“…This shows the potential of tannins to reduce rumen microbial activity. Dickhoefer et al (2016) found a linear decline on urinary excretion, not only of uric acid but of allantoin as well. The difference may be due to the level of tannins, since these authors included tannins up to 6%.…”

“…Using diets of up to 6% of tannins, Ahnert et al (2015) found a linear reduction in urinary N and a linear increase in faecal N, and, regardless the level of tannins in diets, N retention was higher with tannins than without. The urinary purine derivatives declined linearly when tannins were increased up to 6% in the study of Dickhoefer et al (2016).…”