Changes in ruminal fermentation and microbial population of feedlot Nellore cattle fed crude glycerin and virginiamycin

Abstract

The objective of this experiment was to evaluate the effects of crude glycerin (CG) and virginiamycin (VM) diets on ruminal fermentation and microbial population of feedlot Nellore cattle. Eight rumen fistulated bulls (BW = 600 ± 34 kg; 26 ± 3 months) were used in a replicated 4 × 4 Latin square (21-d periods) with 2 × 2 factorial arrangement of treatments: diets without virginiamycin (VM−) or virginiamycin at 25 mg/kg DM (VM+) combined with diets without crude glycerin (CG−) or CG (80% glycerol) at 100 g/kg DM (CG+). The sugar cane bagasse was used as the exclusive roughage in the proportion of 200 g/kg in dry matter of diet and crude glycerin replaced corn in the diet formulation. Ruminal samples were collected immediately before feeding and at 3, 6, 12 and 18 h post feeding on days 20 and 21 of the sampling week. Data were analyzed in a replicated 4 × 4 Latin square with a 2 × 2 factorial using the MIXED procedure of SAS (SAS Inst., Inc., Cary, NC). There were no CG × VM interactions for any variable measured (P ≥ 0.10). The intake of DM had a tendency to be greater in CG+ than CG− diets (P = 0.07). Apparent total tract digestibilities of nutrients were similar among diets (P ≥ 0.10). Diets with CG or VM had similar values of pH (mean = 6.15; P ≥ 0.10). Data showed that CG or VM did not affect the concentration of total VFA (116.92 mM; P ≥ 0.10). The proportion of propionate increased 27.5% in CG+ diets, regardless of VM inclusion (P = 0.01). Acetate:propionate ratio was lower in CG+ compared to CG− diets (3.58 vs. 2.12; P ≥ 0.10). Valerate and butyrate proportion was greater in CG+ than CG− diets (P < 0.05). The inclusion of VM or CG did not alter the relative abundance of fibrolityc bacteria (P ≥ 0.10). Total protozoa counts (P = 0.052) and Metadinium spp. (P = 0.058) had a tendency to decrease in VM+ than VM− diets (P < 0.10). Crude glycerin had positive effects on rumen fermentation products and can replace virginiamycin with increment of Megasphaera elsdenii abundance. However, combining virginiamycin and glycerin does not affect positively rumen fermentation and growth of bacteria that metabolize lactate. 1. Introduction Feedlots diets of beef cattle are generally rich in grains with high starch content. The great concentration of starch present in

Metabolism, Ketosis Treatment and Milk Production after Using Glycerol in Dairy Cows: A Review

“…M. elsdenii also produces propionate. In other studies, the abundance of Megasphaera elsdenii doubled after the use of crude glycerol (80% glycerol), but without a noticeable effect on rumen protozoa [ 40 ]. The presented changes in the rumen fluid microbiome explain the most frequently observed dynamics and directions of volatile fatty acid (VFA) changes.…”

Glycerol use in dairy diets: A systemic review

“…Increased feed intake with glycerol suggests improved energy utilization efficiency by ruminal microbiota (Andrade et al., 2018). Moreover, the physical characteristics of glycerol, such as viscosity, could maintain feed particles aggregate and reduce ruminal fill (Castagnino et al., 2018). Recently, Bajramaj et al.…”

Effect of Feeding Glycerin on Ruminal Environment and In Situ Degradability of Feedstuffs in Young Bulls

“…Fernando et al [33] indicated that an increase in Selenomonas ruminantium populations together with other species such as Megasphaera elsdenii could decrease the amount of lactic acid in high-concentrate diets, since these microorganisms are considered lactate-using species. Castagnino et al [9] noted, despite not finding an increase in the population of Selenomonas ruminantium , that when adding 10% glycerin to the diets of beef cattle, there was an increase in Megasphaera elsdenii ; furthermore, they did not find changes in other populations such as fibrolytic bacteria ( Ruminococcus albus and Fibrobacter succinogenes ).…”

“…In our case, no differences were found on the effective degradability for two very different fibrous raw materials (barley straw and sugar beet pulp), when glycerin was increased. In addition, Castagnino et al [9] reported that high-concentrate diets with 10% glycerin that were fed to beef cattle did not affect the apparent digestibility of DM or NDF, nor the abundance of fibrolityc bacteria.…”

“…Recently, a potential effect in preventing acidosis has been indicated for glycerin, due to the promoting effect of glycerol on lactate-using bacteria such as Megasphaera elsdenii [9], but there are few studies on fattening ruminants that extensively analyse the effect of glycerin on the ruminal metabolism, ruminal population and feedstuff degradability. As a consequence, the hypothesis of this work was that the ruminal fermentation of glycerin could benefit some microorganisms, impeding negative effects on the ruminal metabolism and on the degradability of dietary ingredients.…”