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801.
802.
Gengzhi Ding Ying Chang Liping Zhao Zhenming Zhou Liping Ren Qingxiang Meng 《畜牧与生物技术杂志(英文版)》2014,5(1):24
Live yeast (Saccharomyces cerevisiae) constitutes an effective additive for animal production; its probiotic effect may be related to the concentrate-to-forage ratio (CTFR). The objective of this study was to assess the effects of S. cerevisiae (SC) on fiber degradation and rumen microbial populations in steers fed diets with different levels of dietary concentrate. Ten Simmental × Local crossbred steers (450 ± 50 kg BW) were assigned to a control group or an SC group. Both groups were fed the same basal diet but the SC group received SC supplementation (8 × 109 cfu/h/d through the ruminal fistula) following a two-period crossover design. Each period consisted of four phases, each of which lasted 17 d: 10 d for dietary adaptation, 6 d for degradation study, and 1 d for rumen sample collection. From the 1st to the 4th phase, steers were fed in a stepwise fashion with increasing CTFRs, i.e., 30:70, 50:50, 70:30, and 90:10. The kinetics of dry matter and fiber degradation of alfalfa pellets were evaluated; the rumen microbial populations were detected using real-time PCR. The results revealed no significant (P > 0.05) interactions between dietary CTFR and SC for most parameters. Dietary CTFR had a significant effect (P < 0.01) on degradation characteristics of alfalfa pellets and the copies of rumen microorganism; the increasing concentrate level resulted in linear, quadratic or cubic variation trend for these parameters. SC supplementation significantly (P < 0.05) affected dry matter (DM) and neutral detergent fiber (NDF) degradation rates (cDM, cNDF) and NDF effective degradability (EDNDF). Compared with the control group, there was an increasing trend of rumen fungi and protozoa in SC group (P < 0.1); copies of total bacteria in SC group were significantly higher (P < 0.05). Additionally, percentage of Ruminobacter amylophilus was significantly lower (P < 0.05) but percentage of Selenomonas ruminantium was significantly higher (P < 0.05) in the SC group. In a word, dietary CTFR had a significant effect on degradation characteristics of forage and rumen microbial population. S. cerevisiae had positive effects on DM and NDF degradation rate or effective degradability of forage; S. cerevisiae increased rumen total bacteria, fungi, protozoa, and lactate-utilizing bacteria but reduced starch-degrading and lactate-producing bacteria. 相似文献
803.
Background
Methane (CH4) emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency. The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake (RFI) while offered (i) a low energy high forage (HF) diet followed by (ii) a high energy low forage (LF) diet. Ruminal fluid was collected from 14 high (H) and 14 low (L) RFI animals across both dietary periods. Quantitative real time PCR (qRT-PCR) analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes. Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance, rumen fermentation variables and diet digestibility.Results
Abundance of methanogens, did not differ between RFI phenotypes. However, relative abundance of total and specific methanogen species was affected (P < 0.05) by diet type, with greater abundance observed while animals were offered the LF compared to the HF diet.Conclusions
These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH4 emissions between efficient and inefficient animals, however dietary manipulation can influence the abundance of total and specific methanogen species. 相似文献804.
牛粪湿法厌氧消化规律及载体影响的研究 总被引:5,自引:3,他引:5
在35℃条件下,观察牛粪厌氧消化的沼气产量和生物指标的变化规律及聚丙烯网状空心球、玻璃纤维和碳纤维膜载体对牛粪厌氧消化性能的影响。结果表明:5%牛粪在厌氧发酵过程中,pH值在发酵的第3 d降到最低,在发酵的第7 d升高到7以上;沼气的产量约在发酵的第9 d达到高峰,而后逐渐降低;COD的去除主要发生在发酵的第4~8 d;发酵产物细菌数量在发酵第6 d达到高峰,在第12 d降低到一个基本相对稳定的水平;辅酶F420活性与其细菌数量在时间和数量方面有着相同的变化规律。聚丙烯网状球形载体表面附着较多的微生物,由此延长产气高峰期,并显著提高沼气产量(p<0.05),以及显著降低反应器厌氧微生物的流失(p<0.01)。 相似文献
805.
Alessandra Lagomarsino Brigitte A. Knapp M. Cristina Moscatelli Paolo De Angelis Stefano Grego Heribert Insam 《Journal of Soils and Sediments》2007,7(6):399-405
Background, Aims, and Scope The genetic structure and the functionality of soil microbes are both important when studying the role of soil in the C cycle
in elevated CO2 scenarios. The aim of this work was to investigate the genetic composition of the fungal community by means of PCR-DGGE and
the functional diversity of soil micro-organisms in general with MicroResp-based community level physiological profiling (CLPP)
in a poplar plantation (POPFACE) grown under elevated [CO2] with and without nitrogen fertilization.
Materials and Methods The POPFACE experimental plantation and FACE facility are located in central Italy, Tuscania (VT). Clones of Populus alba, Populus nigra and Populus x euramericana were grown, from 1999 to 2004, in six 314 m2 plots treated either with atmospheric (control) or enriched (550 μmol mol−1) CO2 with FACE (Free Air CO2 Enrichment) technology in each growing season. Each plot is divided into six triangular sectors, with two sectors per poplar
genotype: three species × two nitrogen levels. After removal of the litter layer one soil core per genotype (10 cm wide, 20
cm depth) was taken inside each of the three sectors in each plot, for a total of 36 soil cores (3 replicates × 2 [CO2] × 2 fertilization × 3 species) in October 2004 and in July 2005. DNA was extracted with a bead beating procedure. 18S rDNA
gene fragments were amplified with PCR using fungal primers (FR1 GC and FF390). Analysis of CLPP was performed using the MicroResp
method. Carbon substrates were selected depending on their ecological relevance to soil and their solubility in water. In
particular rhizospheric C sources (carboxylic acids and carbohydrates) were chosen considering the importance of root inputs
for microbial metabolism.
Results The fertilization treatment differentiated the fungal community composition regardless of elevated [CO2] or the poplar species; moreover the number of fungal species was lower in fertilized soil. The effect of elevated [CO2] on the fungal community composition was evident only as interaction with the fertilization treatment as, in N-sufficient
soils, the elevated [CO2] selected a different microbial community. For CLPP, the differ ent poplar species were the main factors of variation. The
FACE treatment, on average, resulted in lower C utilization rates in un-fertilized soils and higher in fertilized soils.
Discussion Fungal biomass and fungal composition depend on different factors: from previous studies we know that the greater quantity
and the higher C/N ratio of organic inputs under elevated [CO2] influenced positively the fungal biomass both in fertilized and in un-fertilized soil, whereas nitrogen availability resulted
to be the main determinant of fungal community composition in this work. Whole active microbial community was directly influenced
by the soil nutrient availability and the poplar species. Under elevated CO2 the competition for N with plants strongly affected the microbial communities, which were not able to benefit from added
rhizospheric substrates. Under Nsufficient conditions, the increase of microbial activity due to [CO2] enrichment was related to a more active microbial community, favoured by the current availability of C and N.
Conclusions Different factors influenced the microbial community at different levels: poplar species and root exudates affected the functional
properties of the microbial community, while the fungal specific composition (as seen with DGGE) remained unaffected. On the
other hand, factors such as N and C availability had a strong impact on the community functionality and composition. Fungal
community structure reflected the availability of N in soils and the effect of elevated [CO2] on community structure and function was evident only in N-sufficient soils. The simultaneous availability of C and N was
therefore the main driving force for microbial structure and function in this plantation.
Recommendations and Perspectives Using the soil instead of soil extracts for CLPP determination provides a direct measurement of substrate catabolism by microbial
communities and reflects activity rather than growth because more immediate responses to substrates are measured. Further
applications of this approach could include selective inhibition of different microbial functional groups to investigate specific
CLPPs. To combine the structural analysis and the catabolic responses of specific microbial communities (i.e. fungi or bacteria)
could provide new outlooks on the role of microbes on SOM decomposition.
ESS-Submission Editor: Dr. Kirk Semple (k.semple@lancaster.ac.uk) 相似文献
806.
通过室内泥浆体系模拟试验,研究了混合微生物菌群(嗜热菌和多环芳烃特异性降解菌),在40℃条件下(两类微生物均能较快生长繁殖),对泥浆体系中代表性多环芳烃菲、芘的去除效果及其影响因素(水土比,葡萄糖、淀粉、水杨酸及其浓度)。结果表明:泥浆体系中混合微生物菌群对多环芳烃的去除效果显著(P0.01),单日菲去除率最大可达20.0%,芘达15.3%。随着反应进程的进行,菲和芘的去除率提高,去除速率则逐步降低,菲的半衰期1.8天小于芘4.9天,因此菲的去除较芘更快。试验得到该泥浆体系中混合微生物菌群去除多环芳烃最合适的水土比为2︰1,碳源为葡萄糖,浓度TOC_(葡萄糖):TOC_(PAHs)为2︰1。该研究结果可为泥浆体系中混合微生物菌群强化修复多环芳烃污染土壤的技术研发提供理论基础和技术支撑。 相似文献
807.
《动物营养(英文)》2021,7(4):1352-1359
The objective of this experiment was to investigate the potential benefits of active dry yeast (ADY) on the growth performance, rumen fermentation, nutrient digestibility, and serum parameters of weaned beef calves. Thirty Simmental crossbred male calves (body weight = 86.47 ± 4.41 kg and 70 ± 4 d of age) were randomly divided into 2 groups: control (CON) (fed basal ration) and ADY (fed basal ration and 5 g/d ADY per calf). The dietary concentrate-to-roughage ratio was 35:65. All the calves were regularly provided rations 3 times a day at 07:00, 13:00, and 19:00 and had free access to water. The experiment lasted for 60 d. The average daily gain of ADY group was higher (P = 0.007) than that of the CON group, and the ratio of feed intake to average daily gain in the ADY group was reduced (P = 0.022) as compared to the CON group. The concentration of ruminal ammonia-N was higher (P = 0.023) in the CON group than that in the ADY group, but an opposite trend of microbial protein was found between the 2 groups. Also, the ruminal concentrations of propionate and butyrate were higher (P < 0.05) in the ADY group than those in the CON group. Calves fed ADY exhibited higher (P < 0.05) crude protein and neutral detergent fiber digestibility. Supplementation of ADY increased (P < 0.05) the contents of glucose, glutathione peroxidase, superoxide dismutase, immunoglobulin A, immunoglobulin M, and interleukin 10 in the serum of calves, but an opposite trend was observed in malondialdehyde, interleukin 1 beta, and tumor necrosis factor alpha contents between the 2 groups. In conclusion, dietary supplementation with ADY could improve the growth performance, rumen fermentation, nutrient digestibility, antioxidant ability, and immune response of weaned beef calves. 相似文献
808.
Debasis Mitra Snežana Anđelković Ansuman Senapati Tanja Vasić A. N. Ganeshamurthy 《Communications in Soil Science and Plant Analysis》2020,51(5):645-657
ABSTRACTPhosphate-solubilizing microbes (PSM) are widely distributed in the rhizosphere and helps plant to acquire phosphates from soil. The availability of phosphates in soil are governed by several factors among which the proton exchange capacity has been regarded to be the most important factor involved in cation complex formations with soluble phosphates making them unavailable to plants, thereby disturbing the phosphorus cycling events found in arable soils. PSM solubilizes the cation complexes and thereby improves the functioning of phosphorus cycle in soil. In addition to involvement in biogeochemical cycling events, PSM have been also found to have antagonistic potential against several plant phytopathogens. These biocontrol microbes represent the most abundant groups of soil microflora. Among which some nutrient solubilizers have been used for effective biocontrol of important plant diseases. This review article shows contributions of different plant growth promoters used in nutrient and disease management practices in agriculture.Abbreviations: P (phosphorus), PSM (phosphate-solubilizing microbes), PSB (phosphate-solubilizing bacteria), PSF (phosphate-solubilizing fungi), PGPM (plant growth-promoting microbes), PGPB (plant growth-promoting bacteria), SAR (systemic acquired resistance), ISR (induced systemic resistance), TCP (tri-calcium phosphate), HCN (hydrogen cyanide), IAA (indole-3-acetic acid), aPhosphorus [(SSP) single super phosphate, RP (rock phosphate), PM (poultry manure) and FYM (farm yard manure)], PAL (phenylalanine ammonia lyase), ESI-MS (electrospray ionization mass spectrometry), DAPG (2,4-diacetylphloroglucinol) and NMR (1H nuclear magnetic resonance). 相似文献
809.
810.
滇池西岸4种针叶林的土壤微生物与酶活性 总被引:3,自引:0,他引:3
采用实地调查与室内实验分析相结合,对位于高原湿地滇池西岸森林公园现存4种针叶林:云南松、华山松+云南油杉混交、云南油杉、柏树的林下土壤微生物特征及酶活性进行研究.结果表明:4种针叶林中,土壤微生物数量差异性显著,呈现出从混交林到纯林逐渐减少趋势.在微生物区系组成中,细菌占绝对优势,放线菌次之,真菌最少,且均随着土层的加... 相似文献