Changes in the Fermentation and Bacterial Community by Artificial Saliva pH in RUSITEC System

The purpose of the study was to assess the artificial saliva (AS) pH on ruminal fermentation and rumen bacteria community in the rumen simulation technique (RUSITEC) system. The experiment was performed in two treatments (low AS pH vs. high AS pH) with four replicates. The low AS pH was sustained by altering the composition of the AS (NaHCO3 from 9.8 to 1.96 g/L, Na2HPO4 from 9.3 to 1.86 g/L) according to McDougall's method. The diets were supplemented with 16 g basic diets with forage to the concentrate ratio of 50:50. The experiments were conducted over 13-day incubation periods, with 9 days adaption and 4 days sample collection. The results showed low AS pH decreased dry matter (DM) degradability (64.37 vs. 58.67%), organic matter (OM) degradability (64.38 vs. 59.32%), neutral detergent fiber (NDF) degradability (46.87 vs. 39.94%), acid detergent fiber (ADF) degradability (38.16 vs. 31.13%), and crude protein (CP) degradability (70.33 vs. 62.99%), respectively. Compared with the high AS pH, the low AS pH increased the proportion of butyrate (P = 0.008) and decreased the proportion of propionate (P < 0.001). At the bacteria community, the low AS pH increased the abundances of Spirochaetes (P = 0.001) and Synergistetes (P = 0.004) and decreased the Verrucomicrobia abundance (P = 0.004) in solid-associated bacteria. At the genus level, the low AS pH increased the abundance of Lactobacillus (P = 0.050) and decreased the abundance of Schwartzia (P = 0.002) in solid-associated bacteria. The abundances of Prevotellaceae_YAB2003_group (P = 0.040), Schwartzia (P = 0.002), and Ruminobacter (P = 0.043) were lower in the low AS pH group compared with the high AS pH group in liquid-associated bacteria. Low AS pH decreased the number of Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes (P < 0.001) both in the solid- and liquid-associated bacteria, respectively. The results of the present study included three groups of bacteria communities according to the different sensitives to rumen pH: the abundances of Lactobacillus, Succinivibrio, and Prevotella_7 are increased with decreasing AS pH; the amounts of R. albus, R. flavefaciens, F. succinogenes as well as the abundances of Schwartzia and Ruminobacter decreased with the reducing AS pH; the abundances of Selenomonas_1, Rikenellaceae_RC9_gut_group, and Succiniclasticum were not affected by the AS pH in RUSTITEC.

РОСЛИННІ ПРОБІОТИКИ: ВПЛИВ НА РОСЛИНИ В УМОВАХ СТРЕСУ

Світове сільське господарство стоїть на порозі нової революції. Агровиробники прагнуть використовувати менше мінеральних добрив та пестицидів і при цьому отримувати високі врожаї. Одим із інструментів, що можуть сприяти цьому, є рослинні пробіотики. Тому мета цієї статті дослідити вплив корисних мікроорганізмів на сільськогосподарські культури, а саме на те які бактерії чи гриби можуть сприяти в боротьбі рослин проти стресу від посухи, засолених ґрунтів чи патогенів. Важливим аспектом дослідження стала також інформація про те, що міроорганізи позитивно впли-вають на поглинання рослинами поживних речовин. Всі ці фактори негативно впливають на вирощування кукурудзи на силос (Zea mays L.), особливо в умовах швидкої зміни клімату. Для проведення дослідження було проаналізовано літера-турні джерела зарубіжних та вітчизняних авторів. В результаті дослідження було з’ясовано, що на стрес від посухи у посівах кукурудзи впливає Azospirillum lipoferum. На засолених ґрунтах рослини кукурудзи краще переживають стрес за інокуляції рослин Pseudomonas syringae, Enterobacter aerogenes, P. fluorescens, Bacillus aquimaris, Serratia liquefaciens, Gracilibacillus, Staphylococcus, Virgibacillus, Salinicoccus, Bacillus, Zhihengliuella, Brevibacterium, Oceanobacillus, Exiguobacterium, Pseudomonas, Arthrobacter, Halomonas та ін. Дію на патогени в посівах кукурудзи виявляють Pseudomonas fluorescens, Fusarium oxysporum, Fusarium verticillioides, Pseudomonas, Bacillus cereus. На засвоєння рослинами кукурудзи по-живних речовин впливають Pseudomonas alcaligenes, Bacillus polymyxa, Mycobacterium phlei, Burkholderia, Bacillus spp., Herbaspirillum, Enterobacteriales, Streptomyces pseudovenezuelae, Ruminobacter amylophilus, Fibrobacter succinogenes, Enterococcus faecium, Арбускулярні мікоризні гриби, Enterobacter E1S2, Klebsiella MK2R2, Bacillus B2L2, Azospirillum brasilence, Micromonospora, Streptomyces, Bacillus, Hyphomicrobium, Rhizobium, Azohydromonas spp., Azospirillum spp. та інші. Цікавим фактом, що було виявлено в результаті цієї статті стало те, що деякі мікроорганізми можуть виявляти позитивну дію на рослину-госоподаря не лише в одному напрямку як наприклад, Pseudomonas fluorescens.

Effects of supplementation of nonforage fiber source in diets with different starch levels on growth performance, rumen fermentation, nutrient digestion and microbial flora of Hu lambs

The objectives were to evaluate the effects of fiber source and dietary starch level on growth performance, nutrient digestion, rumen parameters and rumen bacteria in fattening Hu lambs. A total of 360 Hu lambs (BW = 24.72 ± 0.14 kg, 2 months old) were subjected to a 2×3 factorial arrangement. Lambs randomly assigned 6 treatments with 6 repetitions (10 lambs per repetition) of each treatment. Six treatments were formulated to include the fiber sources with three starch levels. The experiment lasted a 63 d. The amount of feed, orts and total feces were sampled on 42nd day of the experiment. Rumen fluid samples were collected after 2 h of morning feeding on day 56. Rumen contents were collected last day after the selected lambs were slaughtered. Increasing the starch content decreased the digestibility of neutral detergent fiber (NDF, P = 0.005). Increasing the starch level increased the proportions of propionate (P = 0.002) and valerate (P = 0.001) and decreased the proportion of acetate (P < 0.001) and the ratio of acetate to propionate (P = 0.005). The abundance of Fibrobacter succinogenes was affected by an interaction between the fiber source and the starch level (P < 0.001). Fibrobacter succinogenes tended to be greater in lambs fed SH than in lambs fed BP (P = 0.091), which was a greater in lambs fed high starch levels than in lambs fed low starch levels (P = 0.014). Increasing the starch level increased Streptococcus bovis abundance (P = 0.029) and decreased total bacteria (P = 0.025). At the genus level, increasing the starch level reduced the abundance of Butyrivibrio_2 (P = 0.020). Nevertheless, the final bodyweight (BW) and acid detergent fiber (ADF) digestibility were greater (P < 0.01) in lambs fed soybean hull (SH) than in lambs fed BP. The proportion of butyrate was greater (P = 0.005), while the rumen pH was lower (P = 0.001) in lambs fed beet pulp (BP) than in those fed SH. The abundances of Succiniclasticum, Candidatus_Saccharimonas, Ruminococcus_1 and Christensenellaceae_R-7 were greater in lambs fed SH than in those fed BP (P < 0.050), whereas the abundance of Fibrobacter was lower (P = 0.011). The predominant microbial phyla in all of the groups were Firmicutes, Bacteroidetes and Fibrobacteres. Changing the starch level for fiber sources mainly changed the rumen community in terms of the phylum and genus abundances. Lambs fed SH with low starch level increased the final BW without affecting TVFA concentrations.

In Vivo Competitions between Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminoccus albus in a Gnotobiotic Sheep Model Revealed by Multi-Omic Analyses

ABSTRACT Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens are the three predominant cellulolytic bacterial species found in the rumen. In vitro studies have shown that these species compete for adherence to, and growth upon, cellulosic biomass. Yet their molecular interactions in vivo have not heretofore been examined. Gnotobiotically raised lambs harboring a 17-h-old immature microbiota devoid of culturable cellulolytic bacteria and methanogens were inoculated first with F. succinogenes S85 and Methanobrevibacter sp. strain 87.7, and 5 months later, the lambs were inoculated with R. albus 8 and R. flavefaciens FD-1. Longitudinal samples were collected and profiled for population dynamics, gene expression, fibrolytic enzyme activity, in sacco fibrolysis, and metabolite profiling. Quantitative PCR, metagenome and metatranscriptome data show that F. succinogenes establishes at high levels initially but is gradually outcompeted following the introduction of the ruminococci. This shift resulted in an increase in carboxymethyl cellulase (CMCase) and xylanase activities but not in greater fibrolysis, suggesting that F. succinogenes and ruminococci deploy different but equally effective means to degrade plant cell walls. Expression profiles showed that F. succinogenes relied upon outer membrane vesicles and a diverse repertoire of CAZymes, while R. albus and R. flavefaciens preferred type IV pili and either CBM37-harboring or cellulosomal carbohydrate-active enzymes (CAZymes), respectively. The changes in cellulolytics also affected the rumen metabolome, including an increase in acetate and butyrate at the expense of propionate. In conclusion, this study provides the first demonstration of in vivo competition between the three predominant cellulolytic bacteria and provides insight on the influence of these ecological interactions on rumen fibrolytic function and metabolomic response. IMPORTANCE Ruminant animals, including cattle and sheep, depend on their rumen microbiota to digest plant biomass and convert it into absorbable energy. Considering that the extent of meat and milk production depends on the efficiency of the microbiota to deconstruct plant cell walls, the functionality of predominant rumen cellulolytic bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens, has been extensively studied in vitro to obtain a better knowledge of how they operate to hydrolyze polysaccharides and ultimately find ways to enhance animal production. This study provides the first evidence of in vivo competitions between F. succinogenes and the two Ruminococcus species. It shows that a simple disequilibrium within the cellulolytic community has repercussions on the rumen metabolome and fermentation end products. This finding will have to be considered in the future when determining strategies aiming at directing rumen fermentations for animal production.

Application of the bacterial strains Ruminobacter amylophilus, Fibrobacter succinogenes and Enterococcus faecium for growth promotion in maize and soybean plants

Ruminobacter amylophilus, Fibrobacter succinogenes and Enterococcus faecium have characteristics that are similar to those of plant growth-promoting bacteria and can be used to promote plant development and reduce production costs. These bacteria were isolated from fistulated ruminants and are gram-negative, anaerobic or facultative anaerobic. These bacteria are frequently used to increase animal productivity through the production of many enzymes responsible for the carbon cycle and the release of other nutrients by organic matter decomposition. The bacteria R. amylophilus, F. succinogenes and E. faecium have growth promotion abilities, such as phosphorus solubilization, nitrogen promotion, and indole acetic acid and siderophore production. Tests were performed under greenhouse conditions with soybean and maize crops with five treatments and six replications. The first treatment was the control (without inoculant); the other treatments included each species of bacteria, and there was a treatment with a mixture (mix) of the three bacteria. F. succinogenes increased the root dry mass of maize by 21.4%, as well as the nitrogen and phosphorus contents, compared to the control. R. amylophilus and E. faecium decreased the phosphorus concentration in shoots of maize, and R. amylophilus increased the soil biomass carbon by 76.39% compared to the mix under maize cultivation, while E. faecium decreased the soil biomass carbon by 56.78% compared to the mix under soybean cultivation. The present study verified that Ruminobacter amylophilus, Fibrobacter succinogenes and Enterococcus faecium presented plant growth-related abilities and could be used to improve plant development, reducing the necessity of chemical fertilizers

Effects of the Appropriate Addition of Antioxidants from Pinus densiflora and Mentha canadensis Extracts on Methane Emission and Rumen Fermentation

This study aimed to investigate the optimal addition of terpene-based Pinus densiflora and Mentha canadensis extracts, with antioxidant and methane reduction effects, as feed supplements to ruminants. Two cannulated steers (450 ± 30 kg), consuming Timothy Hay and a commercial concentrate (60:40, w/w) twice daily (at 09:00 and 17:30) at 2% of body weight, with free access to water and a mineral block, were used as rumen fluid donors. In vitro fermentation experiments, with Timothy Hay as the substrate, were conducted with P. densiflora and M. canadensis extracts as supplements to achieve concentrations of 30, 50, and 70 mg/L on a Timothy Hay basis. Fibrobacter succinogenes decreased in proportion upon P. densiflora and M. canadensis extract supplementation at 50 mg/L, while the dry matter degradability of the feed was not significantly different (p < 0.05). Methane emission was significantly lower in the 50 and 70 mg/L treatment groups, for both extracts, at 12 h (p < 0.05). Based on methane production and antioxidant activity, our study suggests that 30 mg/L addition is the most appropriate level of supplementation.

Microorganismos asociados a la mejora de digestión y absorción de nutrientes con impacto en el peso y salud de cuyes

En los últimos años la demanda de la carne de cuyes (Cavia porcellus) ha crecido por la alta popularidad de la cocina peruana. Asimismo, muchos criadores están buscando formas de aumentar la producción a bajo costo y con un mayor rendimiento. Recientemente, el microbioma intestinal se ha asociado con varios procesos biológicos, siendo su composición o alteración relacionado con el desarrollo de ciertas enfermedades y/o ventajas transmitidas al hospedero (individuo). A fin de identificar, comprender y descubrir el potencial metabólico de microrganismos para la mejora digestión y absorción de nutrientes se desarrolló el presente estudio. En este estudio, 21 muestras del ciego de cuyes de las tres principales líneas de crianza (Andina, Inti y Perú) criados en un mismo ambiente fueron investigados utilizando la metodología de Shotgun-Metagenomics. Luego del análisis bioinformático solo ocho muestras pasaron los criterios de calidad. El reino bacteria, fue el más representado en el análisis. Se identificaron las diferencias entre las líneas de cuyes, en base a la abundancia relativa de bacterias en cada muestra. Las especies de bacterias encontradas como Bifidobacterium longum, Fibrobacter succinogenes, y Faecalibacterium prausnitzii, están envueltas en diversos procesos metabólicos, como la digestión y absorción de nutrientes de la celulosa y sintetizar moléculas beneficiosas para la buena salud del individuo. Las bacterias identificadas podrían representar un potencial en el desarrollo y elaboración de probioticos aplicados a la mejora del bienestar salubre y de producción de carne de cuyes en el Departamento de Amazonas.

Publisher Correction: Deciphering the unique cellulose degradation mechanism of the ruminal bacterium Fibrobacter succinogenes S85

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Rumen degradability and gas production as influenced by different strains of Bacillus thuringiensis

The effect of six Bacillus thuringiensis (Bt) strains on diet degradability was evaluated using an in vitro gas production technique. Spores (5.7 × 106 spores) of different Bt strains (907, 1192, 2036, 2493, 2496, and S1185) plus a control (no spores) were used as treatments with four replicates (inocula) in duplicate. Fermentation processes were evaluated and ruminal microorganisms were quantified. Compared with the control, the Bt907 strain decreased dry matter (DM) and organic matter (OM) degradability without affecting the Fibrobacter succinogenes population, whereas the other strains reduced this population without altering DM and OM degradability.

Deciphering the unique cellulose degradation mechanism of the ruminal bacterium Fibrobacter succinogenes S85

Fibrobacter succinogenes S85, isolated from the rumen of herbivores, is capable of robust lignocellulose degradation. However, the mechanism by which it achieves this is not fully elucidated. In this study, we have undertaken the most comprehensive quantitative proteomic analysis, to date, of the changes in the cell envelope protein profile of F. succinogenes S85 in response to growth on cellulose. Our results indicate that the cell envelope proteome undergoes extensive rearrangements to accommodate the cellulolytic degradation machinery, as well as associated proteins involved in adhesion to cellulose and transport and metabolism of cellulolytic products. Molecular features of the lignocellulolytic enzymes suggest that the Type IX secretion system is involved in the translocation of these enzymes to the cell envelope. Finally, we demonstrate, for the first time, that cyclic-di-GMP may play a role in mediating catabolite repression, thereby facilitating the expression of proteins involved in the adhesion to lignocellulose and subsequent lignocellulose degradation and utilisation. Understanding the fundamental aspects of lignocellulose degradation in F. succinogenes will aid the development of advanced lignocellulosic biofuels.