Effects of increasing concentrations of glycerol in concentrate diets on nutrient digestibility, methane emissions, growth, fatty acid profiles, and carcass traits of lambs1

Abstract

Two experiments were conducted to evaluate the effects of increasing concentrations of glycerol in concentrate diets on total tract digestibility, methane (CH4) emissions, growth, fatty acid profiles, and carcass traits of lambs. In both experiments, the control diet contained 57% barley grain, 14.5% wheat dried distillers grain with solubles (WDDGS), 13% sunflower hulls, 6.5% beet pulp, 6.3% alfalfa, and 3% mineral-vitamin mix. Increasing concentrations (7, 14, and 21% dietary DM) of glycerol in the dietary DM were replaced for barley grain. As glycerol was added, alfalfa meal and WDDGS were increased to maintain similar concentrations of CP and NDF among diets. In Exp.1, nutrient digestibility and CH4 emissions from 12 ram lambs were measured in a replicated 4 × 4 Latin square experiment. In Exp. 2, lamb performance was evaluated in 60 weaned lambs that were blocked by BW and randomly assigned to 1 of the 4 dietary treatments and fed to slaughter weight. In Exp. 1, nutrient digestibility and CH4 emissions were not altered (P = 0.15) by inclusion of glycerol in the diets. In Exp.2, increasing glycerol in the diet linearly decreased DMI (P < 0.01) and tended (P = 0.06) to reduce ADG, resulting in a linearly decreased final BW. Feed efficiency was not affected by glycerol inclusion in the diets. Carcass traits and total SFA or total MUFA proportions of subcutaneous fat were not affected (P = 0.77) by inclusion of glycerol, but PUFA were linearly decreased (P < 0.01). Proportions of 16:0, 10t-18:1, linoleic acid (18:2 n-6) and the n-6/n-3 ratio were linearly reduced (P < 0.01) and those of 18:0 (stearic acid), 9c-18:1 (oleic acid), linearly increased (P < 0.01) by glycerol. When included up to 21% of diet DM, glycerol did not affect nutrient digestibility or CH4 emissions of lambs fed barley based finishing diets. Glycerol may improve backfat fatty acid profiles by increasing 18:0 and 9c-18:1 and reducing 10t-18:1 and the n-6/n-3 ratio.

<b>Ruminal fermentation of Nellore steers fed crude glycerine replacing starch vs. fibre-based energy ingredient in low or high concentrate diets

“…As observed in our study, the intake has been variable and generally depressed in studies where crude glycerine replaced rapidly fermentable starch in diets with high level of concentrate (Parsons, Shelor, & Drouillard, 2009;Avila-Stagno et al, 2013;Meale et al, 2013).…”

Dietary glycerin does not affect meat quality of Ile de France lambs

“…Thus, the increase in the amount of C17:0 may result from the increase in rumen propionate induced by glycerol-rich diets (Drouillard, 2008). An increase in fat C17:0 content has previously been found in Arcott Canadian lambs fed diets containing up to 21% glycerin (Avila-Stagno et al, 2013). This increase in C17:0 does not pose hazards to human health (Scollan et al, 2006).…”

Enteric methane emissions in response to ruminal inoculation of Propionibacterium strains in beef cattle fed a mixed diet

“…The slopes of these best fit linear relationships were used to correct for betweenchamber variability. Conditions of air circulation and sampling procedures were as described by Avila-Stagno et al (2013).…”