Dataset Information

Rumen microbial population dynamics during adaptation to a high-grain diet.

ABSTRACT: High-grain adaptation programs are widely used with feedlot cattle to balance enhanced growth performance against the risk of acidosis. This adaptation to a high-grain diet from a high-forage diet is known to change the rumen microbial population structure and help establish a stable microbial population within the rumen. Therefore, to evaluate bacterial population dynamics during adaptation to a high-grain diet, 4 ruminally cannulated beef steers were adapted to a high-grain diet using a step-up diet regimen containing grain and hay at ratios of 20:80, 40:60, 60:40, and 80:20. The rumen bacterial populations were evaluated at each stage of the step-up diet after 1 week of adaptation, before the steers were transitioned to the next stage of the diet, using terminal restriction fragment length polymorphism (T-RFLP) analysis, 16S rRNA gene libraries, and quantitative real-time PCR. The T-RFLP analysis displayed a shift in the rumen microbial population structure during the final two stages of the step-up diet. The 16S rRNA gene libraries demonstrated two distinct rumen microbial populations in hay-fed and high-grain-fed animals and detected only 24 common operational taxonomic units out of 398 and 315, respectively. The 16S rRNA gene libraries of hay-fed animals contained a significantly higher number of bacteria belonging to the phylum Fibrobacteres, whereas the 16S rRNA gene libraries of grain-fed animals contained a significantly higher number of bacteria belonging to the phylum Bacteroidetes. Real-time PCR analysis detected significant fold increases in the Megasphaera elsdenii, Streptococcus bovis, Selenomonas ruminantium, and Prevotella bryantii populations during adaptation to the high-concentrate (high-grain) diet, whereas the Butyrivibrio fibrisolvens and Fibrobacter succinogenes populations gradually decreased as the animals were adapted to the high-concentrate diet. This study evaluates the rumen microbial population using several molecular approaches and presents a broader picture of the rumen microbial population structure during adaptation to a high-grain diet from a forage diet.

SUBMITTER: Fernando SC

PROVIDER: S-EPMC2976194 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

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Rumen microbial population dynamics during adaptation to a high-grain diet.

Fernando S C SC Purvis H T HT Najar F Z FZ Sukharnikov L O LO Krehbiel C R CR Nagaraja T G TG Roe B A BA Desilva U U

Applied and environmental microbiology 20100917 22

High-grain adaptation programs are widely used with feedlot cattle to balance enhanced growth performance against the risk of acidosis. This adaptation to a high-grain diet from a high-forage diet is known to change the rumen microbial population structure and help establish a stable microbial population within the rumen. Therefore, to evaluate bacterial population dynamics during adaptation to a high-grain diet, 4 ruminally cannulated beef steers were adapted to a high-grain diet using a step-u ...[more]

PMID: 20851965

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Project description:BackgroundBrewers' spent grain (BSG) typically contains 20%?-?29% crude protein (CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing value-added products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates (AlcH and FlaH) showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system (RUSITEC) fed a high-grain diet.ResultsAs compared to the control of grain only, supplementation of FlaH decreased (P <?0.01) disappearances of dry matter (DM), organic matter (OM), CP and starch, without affecting fibre disappearances; while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased (P <?0.01) NH3-N and decreased (P <?0.01) H2 production. Supplementation of FlaH decreased (P <?0.01) the percentage of CH4 in total gas and dissolved-CH4 (dCH4) in dissolved gas. Addition of monensin reduced (P <?0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH4 and H2 emissions. Total microbial nitrogen production was decreased (P <?0.05) but the proportion of feed particle associated (FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH; whereas both indices were reduced (P <?0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance (RA) of bacteria at phylum level, whereas monensin reduced (P <?0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced (P <?0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control; monensin reduced (P <?0.05) RA of genus Prevotella but enhaced Succinivibrio.ConclusionsThe supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH4 production by suppressing H2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.

Project description:The objectives of this study were to characterize changes in the relative mRNA expression of candidate genes and proteins involved in cell cycle regulation, cell proliferation and apoptosis in the ruminal epithelium (RE) of sheep during high-grain (HG) diet adaptation.Twenty sheep were assigned to four groups with five animals each. These animals were assigned to different periods of HG diet (containing 40% forage and 60% concentrate mix) feeding. The HG groups received an HG diet for 7 (G7, n?=?5), 14 (G14, n?=?5) and 28 d (G28, n?=?5), respectively. In contrast, the control group (CON, n?=?5) was fed the forage-based diet for 28 d. The results showed that HG feeding linearly decreased (P?<? 0.001) the ruminal pH, and increased the concentrations of ruminal total volatile fatty acid (linear, P?=?0.001), butyrate (linear, P?<? 0.001), valerate (quadratic P?=?0.029) and the level of IGF-1 (quadratic, P?=?0.043) in plasma. The length (quadratic, P?=?0.004), width (cubic, P?=?0.015) and surface of the ruminal papillae (linear, P?=?0.003) were all enlarged after 14 d of HG diet feeding. HG feeding cubically increased the number of cell layers forming the stratum corneum (SC, P?<? 0.001) and the thickness of the SC (P?<? 0.001) and stratum basale (P?<? 0.001). The proportion of basal layer cells in the RE decreased (linear, P?<? 0.001) in the G0/G1-phase, but it increased linearly (P?=?0.006) in the S-phase and cubically (P?=?0.004) in the G2/M-phases. The proportion of apoptosis cells in G7, G14 and G28 was reduced compared to the CON (quadratic, P?<?0.001). HG diet feeding linearly decreased the mRNA expression of Cyclin E1 (P?=?0.021) and CDK-2 (P?=?0.001) and (P?=?0.027) the protein expression of Cyclin E1. Feeding an HG diet linearly increased the mRNA expression of genes IGFBP-2 (P?=?0.034) and IGFBP 5 (P?<?0.009), while linearly decreasing (P?<?0.001) the IGFBP 3 expression. The expression of cell apoptosis gene Caspase 8 decreased (quadratic, P?=?0.012), while Bad mRNA expression tended to decrease (cubic, P?=?0.053) after HG feeding.These results demonstrated sequential changes in rumen papillae size, cell cycle regulation and the genes involved in proliferation and apoptosis as time elapsed in feeding a high-grain diet to sheep.

Project description:The objective of this study was to evaluate the effect of dried distillers grains with solubles (DDGS) and red-osier dogwood (ROD) extract on in vitro fermentation characteristics, nutrient disappearance, and microbial profiles using the rumen simulation technique. The experiment was a completely randomized design with a 2 × 2 factorial arrangement of treatments and four replicates per treatment. A basal diet [10% barley silage, 87% dry-rolled barley grain, and 3% vitamin and mineral supplement, dry matter (DM) basis] and a DDGS diet (as per basal diet with 25% of wheat DDGS replacing an equal portion of barley grain) were supplemented with ROD extract at 0 and 1% (DM basis), respectively. The experimental period was 17 d, consisting 10 days of adaptation and 7 days of data and sample collection. The substitution of wheat DDGS for barley grain did not affect gas production; disappearances of DM, organic matter, and crude protein; total volatile fatty acid (VFA) production; and microbial protein production. However, replacing barley grain with wheat DDGS increased (P = 0.01) fermenter pH and molar proportion of branched-chain VFA, switched (P = 0.06) the fermentation pattern to higher acetate production due to increased (P = 0.01) disappearance of neutral detergent fiber (NDF), and decreased (P = 0.08) methane (CH4) production. In the basal barley diet, the ROD extract increased the acetate to propionate (A:P) ratio (P = 0.08) and reduced the disappearance of starch (P = 0.06) with no effect on any other variables. No effects of ROD in the DDGS diet were observed. The number of operational taxonomic unit (OTUs) and the Shannon diversity index of the microbial community had little variation among treatments. Taxonomic analysis revealed no effect of adding the ROD extract on the relative abundance of bacteria at the phylum level with either the basal diet or DDGS diet, while at the genus level, the microbial community was affected by the addition of both DDGS and the ROD extract. Prevotella and Fibrobacter were the most abundant genera in the basal diet; however, Treponema became the most abundant genus with the addition of the ROD extract. These results indicated that the substitution of wheat DDGS for barley grain may mitigate enteric CH4 emissions. The trend of reduced starch fermentability and increased NDF disappearance with the addition of ROD extract suggests a reduced risk of rumen acidosis and an improvement in the utilization of fiber for cattle-fed high-grain diet.

Project description:BackgroundThe newly proposed methanogenic order 'Methanomassiliicoccales' is the second largest archaeal population in the rumen, second only to the Methanobrevibacter population. However, information is limited regarding the community of this new order in the rumen.MethodsThis study used real-time PCR and 454 pyrosequencing to explore the abundance and community composition of Methanomassiliicoccales in the rumen of Chinese goats fed a hay (0% grain, n = 5) or a high grain (65% grain, n = 5) diet.ResultsReal-time PCR analysis showed that the relative abundance of Methanomassiliicoccales (% of total archaea) in the goat rumen was significantly lower in the high-grain-diet group (0.5% ± 0.2%) than that in the hay-diet group (8.2% ± 1.1%, P < 0.05). The pyrosequencing results showed that a total of 208 operational taxonomic units (OTUs) were formed from ten samples at 99% sequence identity. All the sequences were identified as Methanomassiliicoccaceae at the family level, and most of the sequences (96.82% ± 1.64%) were further classified as Group 8, 9, and 10 at the Methanomassiliicoccales genus level in each sample based on the RIM-DB database. No significant differences were observed in the number of OTUs or Chao1's, Shannon's or Pielou's evenness indexes between the hay- and high-grain-diet groups (P ≥ 0.05). PCoA analysis showed that diet altered the community of Methanomassiliicoccales. At the genus level, the relative abundances of Group 10 (67.25 ± 12.76 vs. 38.13 ± 15.66, P = 0.012) and Group 4 (2.07 ± 1.30 vs. 0.27 ± 0.30, P = 0.035) were significantly higher in the high-grain-diet group, while the relative abundance of Group 9 was significantly higher in the hay-diet group (18.82 ± 6.20 vs. 47.14 ± 17.72, P = 0.020). At the species level, the relative abundance of Group 10 sp. (67.25 ± 12.76 vs. 38.13 ± 15.66, P = 0.012) and Group 4 sp. MpT1 (2.07 ± 1.30 vs. 0.27 ± 0.30, P = 0.035) were significantly higher in the high-grain-diet group, while the relative abundance of Group 9 sp. ISO4-G1 was significantly higher in the hay-diet group (12.83 ± 3.87 vs. 42.44 ± 18.47, P = 0.022).ConclusionsOnly a few highly abundant phylogenetic groups dominated within the Methanomassiliicoccales community in the rumens of Chinese goats, and these were easily depressed by high-grain-diet feeding. The relatively low abundance suggests a small contribution on the part of Methanomassiliicoccales to the rumen methanogenesis of Chinese goats.

Dataset Information

Rumen microbial population dynamics during adaptation to a high-grain diet.

Publications

Rumen microbial population dynamics during adaptation to a high-grain diet.

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