Effects of Different Vegetable Planting Modes on Soil Microbial Flora and Enzyme Activity

To investigate the effects of different vegetable growing regions and planting modes on soil quality,soils in high,medium and low altitude areas of Guizhou were respectively sampled under different vegetable efficient planting modes,and the variations of soil microbial flora and enzyme activities were analyzed. The soil microbial count and total bacteria of the vegetable efficient cultivation mode were significantly higher than that of the control （traditional planting mode） in each planting area,and the microbial diversity index was also improved to varying de- grees.The soil phosphatase,catalase and urease activities of the vegetable efficient planting mode were higher than that of the control.The soil catalase and urease activities were higher than that of the control by 1.37-1.44 and 1.51-2.80 times. Application of vegetable efficient planting mode in different regions will help to im- prove the soil quality in a given period.

Effect of supplementation of allicin on methanogenesis and ruminal microbial flora in Dorper crossbred ewes

Background： Garlic extracts have been reported to be effective in reducing methanogenesis. Related mechanisms are not well illustrated, however, and most studies have been conducted in vitro. This study investigates the effects of supplementary allicin（AL） in sheep diet on in vivo digestibility, rumen fermentation, and shifts of microbial flora.Methods： Two experiments were conducted using Dorper × thin-tailed Han crossbred ewes. In experiment 1,eighteen ewes（60.0 ± 1.73 kg BW） were randomly assigned for 29 days to either of two dietary treatments： a basal diet or the basal diet supplemented with 2.0 g AL/head？day to investigate supplementary AL on nutrient digestibility and methane emissions. In experiment 2, six ewes（65.2 ± 2.0 kg BW） with ruminal canulas were assigned to the same two dietary treatments as in experiment 1 for 42 days to investigate supplementary AL on ruminal fermentation and microbial flora. The methane emissions were determined using an open-circuit respirometry system and microbial assessment was done by q PCR of 16 S r RNA genes.Results： Supplementary AL increased the apparent digestibility of organic matter（P 〈 0.001）, nitrogen（P = 0.006）,neutral detergent fiber（P 〈 0.001）, and acid detergent fiber（P = 0.002）. Fecal nitrogen output was reduced（P = 0.001）but urinary nitrogen output was unaffected（P = 0.691）, while nitrogen retention（P = 0.077） and nitrogen retention/nitrogen intake（P = 0.077） tended to increase. Supplementary AL decreased methane emissions scaled to metabolic bodyweight by 5.95 %（P = 0.007） and to digestible organic matter intake by 8.36 %（P = 0.009）. Ruminal p H was unaffected（P = 0.601） while ammonia decreased（P = 0.024） and total volatile fatty acids increased（P = 0.024） in response to supplementary AL. Supplementary AL decreased the population of methanogens（P = 0.001） and tended to decrease that of protozoans（P = 0.097）, but increased the populations of F. succinogenes（P 〈 0.001）, R. flavefaciens（P = 0.001）, and B. fibrisolvens（P = 0.001）.Conclusions： Supplementation of AL at 2.0 g/head？day effectively enhanced OM, N, NDF, and ADF digestibility and reduced daily methane emissions（L/kg BW0.75） in ewes, probably by decreasing the population of ruminal protozoans and methanogens.

Dose Response of Ruminal Microbial Flora and Metabolism of Sheep to Supplemental Polyacrylamide

[Objective] The paper was to test the effects of polyacrylamide(PAM) on ruminal microbial flora, activities of fibre-degrading enzymes and voluntary feed intake(VFI) of sheep. [Method] Five of 2-3 years old male Small-tail Han sheep, with body weight of(51.5±4.1) kg and fitted with permanent rumen fistula were used. By a 5×5 Latin square design, sheep were fed a basal diet supplemented with PAM at 0(control), 1.0, 2.0,3.0 and 6.0 g/kg diet, respectively. [Result] PAM supplementation affected VFI and ruminal indexes, and the peak values of them were at 2.0 g/kg diet by 17.9% for VFI, 56.6% for total bacteria, 18.3% for endocellulase, 19.4% for exocellulase and 16.5% for cellubiase( all P<0.05), respectively,compared with control. The NH3-N, protozoal counts, and the protease activity in rumen fluid were all linearly declined, but fungal counts increased linearly. No significant changes were found in pH, activities of xylanase and amylase of rumen fluid. The PCR copies of Fibrobacter succinogenes,Ruminococcus albus, Butyrivibrio fibrisolven and Selenomonas ruminantium increased to maximum of 21.4%, 22.7%, 22.6% and 20.6%(all above P<0.05), whereas these of Prevotella bryantii, Clostridium aminophilum, methanogens and microscopic counting of great coli decreased to maximum of 24.5%, 34.8%, 21.2% and 52.2%(all above P<0.05);but Salmonella bovis and Prevotella ruminicola were not affected by PAM. [Conclusion]PAM supplementation at 2.0 g/kg diet can reduce protozoa but increase bacteria, particularly those species for fibre digestion, and fungi in rumen.The effect of PAM on bacterial species was selective. These changes finally enhanced activities of enzymes for fibre digestion in rumen, and stimu-lated VFI of sheep, suggesting a potential application of PAM in ruminant production.

Analysis of Microbial Community Structure and Diversity in Crop Rhizosphere Soil Based on Illumina NovaSeq Sequencing Platform

[Objectives]To make full use of crop rhizosphere microbial resources.[Methods]Illumina NovaSeq sequencing platform was used to analyze the richness and diversity of microbial community structure in rhizosphere soil of rice and maize crops in Baitu Town,Gaoyao District,Zhaoqing City.[Results]A total of 14936 OTUs of bacteria and 1905 OTUs of fungi were obtained from three samples of rice rhizosphere soil,and 13437 OTUs of bacteria and 1413 OTUs of fungi were obtained from three samples of maize rhizosphere soil.The diversity and richness of bacterial communities were higher than those of fungi.There are differences in soil bacterial and fungal communities among different crop samples.The analysis of species with bacteria difference at genus level among crop rhizosphere soil samples showed that 18 genera with significant differences were obtained from 6 samples;species analysis of fungi at the genus level showed that 3 genera with significant differences were obtained from 6 samples.[Conclusions]The research results of this paper have positive significance for the development and utilization of soil resources in Zhaoqing City and the full exploitation of rice and maize rhizosphere microbial resources.

Recent advances and remaining gaps in our knowledge of associations between gut microbiota and human health

The complex gut microbial flora harbored by individuals(microbiota) has long been proposed to contribute tointestinal health as well as disease. Pre-and probioticproducts aimed at improving health by modifyingmicrobiota composition have already become widelyavailable and acceptance of these products appearsto be on the rise. However, although required forthe development of effective microbiota basedinterventions, our basic understanding of microbiotavariation on a population level and its dynamics withinindividuals is still rudimentary. Powerful new parallelsequence technologies combined with other efficientmolecular microbiota analysis methods now allow forcomprehensive analysis of microbiota composition inlarge human populations. Recent fi ndings in the fi eldstrongly suggest that microbiota contributes to thedevelopment of obesity, atopic diseases, inflammatorybowel diseases and intestinal cancers. Through theongoing National Institutes of Health Roadmap 'HumanMicrobiome Project' and similar projects in other partsof the world, a large coordinated effort is currentlyunderway to study how microbiota can impact humanhealth. Translating findings from these studies intoeffective interventions that can improve health,possibly personalized based on an individuals existingmicrobiota, will be the task for the next decade(s).

Application of Lactic Acid Bacteria(LAB) in Freshness Keeping of Tilapia Fillets as Sashimi

Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria(LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19(obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.

Are our endoscopy patients at risk for pyogenic liver abscess?

This is an editorial comment on a recent publication reporting an increased rate of pyogenic liver abscesses(PLAs) after upper gastrointestinal panendoscopy. Its aim is to critically highlight the findings, limitations and potential clinical implications of this study. Issues of the mucosal barrier, the microbial flora, administration of antibiotics and underlying diseases are discussed. The probability of PLAs after endoscopies is not exactly known and the length of the "incubation period" remains unclear, but a possible causality should already suffice to make us think how to avoid them. Especially in patients with risk factors such as diabetes mellitus, end-stage renal disease, liver cirrhosis, biliary tract infection, and malignancies, the potential risk for PLAs should be considered. Unnecessary insufflation during endoscopy(causing mucosal stretching and microscopic tears) as well as mucosal damage(by direct abrasion with the scope) should be avoided in order to limit the invasiveness of the procedure as much as possible. And, in everyday routine, it should be kept in mind that in patients after endoscopy, especially in those with a breach of the mucosal barrier and significant comorbidities, PLAs can potentially develop and require timely administration of antibiotics as well as further diagnostic and therapeutic steps.

Enzymology properties of two different xylanases and their impacts on growth performance and intestinal microflora of weaned piglets

The enzyme xylanase is more and more widely used in feed production, but different xylanase have different properties, mechanism and application effects. To provide a theoretical basis for choosing more suitable xylanase in feed production, we selected bacterial xylanase(BX), labeled enzyme A, and trichoderma xylanase(TX), labeled enzyme B, and studied the enzymology properties and application effects on growth performance and gut flora in weaned piglets. The results showed that the activity levels of both appear parabolic along with increasing pH or temperature, but the amplitude of enzyme activity changing curves and the pH/temperature of optimal activity level are different, where enzyme A has the optimal activity level at 50 ℃ with a pH value of 5.0. The optimal activity level of enzyme B was achieved at 70 ℃ with a pH around 6.0. Enzyme B suffered very little activity loss with moisture level at16% and temperature from 80℃ to 90 ℃. Enzyme A suffered a big drop in activity level when processed with high temperature from around 80 ℃ to 90 ℃, and it was even completely inactivated at 90 ℃,Enzyme A has very low activity level after being processed in acid environment, but enzyme B has minor changes in activity level with respect to changes in acid level, indicating significantly different enzymatic properties between the two different sources of xylanases. In feeding experiment, the control group, was fed the basal diet, and the BX group and TX group were fed basal diets supplemented with 0,01% bacterial and fungal xylanases, respectively. The results showed that ADG of the BX group and TX group increased by 3.25%(P> 0.05) and 8.22%(P < 0.05), respectively, and the feed conversion ratio decreased by 6.74% and 7.86%(P > 0.05), respectively compared with the control group; TX group had significantly higher(P < 0.05) ADG compared with BX group; BX group and TX group had significantly lower ileum Escherichia coli level than the control group, which were reduced by up to 12.98%(P < 0.05) and 11.68%(P < 0.05), respectively, but the ileal lactic acid bacteria levels were significantly increased by 16.21%(P < 0.01) and 27.02%(P < 0.01),respectively. There were no significant differences(P > 0.05) between BX group and TX group in terms of lactic acid bacteria E. coli level. We concluded that fungal xylanase(enzyme B) has better performances in improving weaned piglet growth and in increasing ileal lactic acid bacteria level compared with bacterial xylanase(enzyme A).

Is Regular Probiotic Practice Safe for Management of Sepsis?

For decades,the gut has been thought to play an important role in sepsis pathogenesis.Sepsis is a serious life-threatening,chronic condition of an infection caused by dysregulated host immune response in most of the intensive care unit patients.Probiotics have dual roles in polymicrobial sepsis i.e.probiotics may induce sepsis in many cases and may prevent its prognosis in many cases.Experimental evidence from both pre-clinical and clinical studies have demonstrated that probiotic therapy ameliorates various inflammatory mediators such as tumor necrosis factor,interleukin-10(IL-10),IL-6,etc.,in septicemia.In addition,probiotic use was also found to reduce the severity of pathological conditions associated with irritable bowel disorder and prevent development of endocarditis in septicemia.On contrary,probiotic therapy in neonatal and athymic adult mice fail to provide any beneficial effects on mortality and sepsis-induced inflammation.Importantly,in few clinical trials probiotic use was found to aggravate sepsis by promoting inflammatory cascade rather than suppressing it.This review discusses various studies regarding the beneficial or harmful effects associated with probiotic therapy in sepsis.