The effect of oak tannin (Quercus robur) and hops (Humulus lupulus) on dietary nitrogen efficiency, methane emission, and milk fatty acid composition of dairy cows fed a low-protein diet including linseed

Abstract

The objective of this study was to test the effects of inclusion of hop pellets (HP) and oak tannin extracts (OT) alone or in combination on N efficiency, methane (CH 4 ) emission, and milk production and composition in 2 experiments with dairy cows fed low-N rations supplemented with linseed. In both experiments, 6 lactating Holstein cows were assigned to 3 dietary treatments in a 3 × 3 duplicated Latin square design (21-d periods). Cows were fed a total mixed ration at a restricted level to meet their nutrient requirements. In experiment 1, 169 g dry matter (DM) of OT or 56 g DM of HP was included separately in the control diet (C1). In experiment 2, the additives were included together (OT-HP) in the control diet (C2) similar to C1. Diet C2 was compared with a control without linseed (C0). In experiment 1, the supplementation of the control diet with OT decreased urinary N excretion by 12%. In experiment 2, the combination of OT and HP decreased urinary N by 7%. Oak tannin extracts and HP alone or in combination did not influence the daily enteric CH 4 production of cows. Cows fed diet C0 produced 17% more enteric CH 4 daily than those fed diet C2. Intake of diet C2, which contained 6.7% extruded linseed on a DM basis (experiment 2), decreased the sum of 6:0 to 14:0 fatty acids (−16%) and palmitic acid (−26%) and increased the stearic acid (+50%), oleic acid (+36%), vaccenic acid (trans-11 18:1; +285%), rumenic acid (cis-9,trans-11 18:2; +235%), and α-linolenic acid (+100%) in milk fat. The supplementation of diet C2 with the OT-HP mixture further improved the milk's fatty acid composition. Intake of the OT alone increased α-linolenic acid by 17.7% (experiment 1). The results of this study show that at the economically acceptable dose we tested, hops had no effect on urinary N excretion, CH 4 emission, milk production, and milk composition. By contrast, supplementation of diets with oak tannin extract can be considered for reducing urinary N excretion. The combination of oak tannin and hops had no more effect than oak tannin alone except on the milk fatty acid profile, which was favorably influenced from a nutritional point of view.

Silage additives to reduce protein degradation during ensiling and evaluation of in vitro ruminal nitrogen degradability

“…Chestnut and oak tannin extracts contained 492 ± 7 and 468 ± 6 g/kg DM, respectively, of total tannins, quantified by a methyl cellulose precipitable tannin assay (Mercurio, Dambergs, Herderich, & Smith, ). Doses were established according to previous experiments for chestnut (Decruyenaere et al., ) and oak tannin extracts (Focant, Froidmont, Archambeau, Dang Van, & Larondelle, in press) and according to additive providers recommendations for acid and zeolite. Sealed silos were stocked in a room from 23 September to 27 October 2016 with a monitored temperature (average = 21.01 ± 1.44°C).…”

Methane Emissions and Milk Fatty Acid Profiles in Dairy Cows Fed Linseed, Measured at the Group Level in a Naturally Ventilated Housing and Individually in Respiration Chambers

“…At supplementation levels of ≤20 g linseed lipids per kg feed DM, there was no reduction in the CH 4 emissions [7][8][9]. Thus, supplementing feed with moderate levels ranging from 26-36 g linseed lipids kg −1 feed DM appears to be the most promising approach to achieve a clear CH 4 reduction with marginal effects on digestion and intake [6,10,11]. In addition, extruded linseed increases the proportion of n-3 polyunsaturated fatty acids (FAs) in milk fat, which is considered beneficial to human health (e.g., [12]).…”

A commentary on methodological aspects of hydrolysable tannins metabolism in ruminant: a perspective view

“…Animal nutritionists, biochemists and microbiologists have focused on the application of dietary feed additives such as plant secondary metabolites in order to modify or manipulate microbial activities of digestive tract of animals (Hassanat and Benchaar 2013;Aguerre et al 2016;Yang et al 2017;Aboagye et al 2018;Costa et al 2018;Salami et al 2018;Focant et al 2019;Wei et al 2019;Zhang et al 2019;Zhou et al 2019). The aim of this manipulation is to enhance feed utilization, reduce greenhouse gas productions and reduce energy loss from animal productions.…”

“…Although using TA, GA, natural HT-rich ingredients (for example, chestnut hydrolysable tannins) and HT-rich feeds (for example, oak leaves, Pistachio by-product and Terminalia oblongata) in ruminant feeding have been explored extensively, not many studies report the information on the concentration of HT metabolites in biological samples (rumen fluid, blood, liver, urine and animal products) (Doce et al 2009;Rahimi et al 2013;Salami et al 2018;Aboagye et al 2019;Focant et al 2019). To the best of my knowledge, data on the concentration of HT metabolites (mostly pyrogallol) in biological samples in ruminant animals fed HT ingredients (TA, GA, natural HT-rich ingredients and HT-rich feeds) are scarce (Martin 1982;Murdiati et al 1992;Frutos et al 2004b;Gonz alez-Barrio et al 2012).…”

“…The application of HT ingredients in ruminant nutrition have been explored in the literature (Doce et al 2009;Rahimi et al 2013;Buccioni et al 2017;Aboagye et al 2018;Salami et al 2018;Focant et al 2019;Wei et al 2019;Zhang et al 2019). However, in most of these researches, the interaction between HT and gut microbiota and the fate of HT metabolites (GA, ellagic acid, pyrogallol, resorcinol, phloroglucinol, catechol and urolithin) in the animal as a whole and animal products were not paid attention nor examined (Doce et al 2009;Rahimi et al 2013;Buccioni et al 2017;Aboagye et al 2018;Salami et al 2018;Focant et al 2019;Wei et al 2019;Zhang et al 2019).…”