Multi-omics reveal mechanisms of high enteral starch diet mediated colonic dysbiosis via microbiome-host interactions in young ruminant.

BACKGROUND: Although rumen development is crucial, hindgut undertakes a significant role in young ruminants' physiological development. High-starch diet is usually used to accelerate rumen development for young ruminants, but always leading to the enteral starch overload and hindgut dysbiosis. However, the mechanism behind remains unclear. The combination of colonic transcriptome, colonic luminal metabolome, and metagenome together with histological analysis was conducted using a goat model, with the aim to identify the potential molecular mechanisms behind the disrupted hindgut homeostasis by overload starch in young ruminants. RESULT: Compared with low enteral starch diet (LES), high enteral starch diet (HES)-fed goats had significantly higher colonic pathology scores, and serum diamine oxidase activity, and meanwhile significantly decreased colonic mucosal Mucin-2 (MUC2) protein expression and fecal scores, evidencing the HES-triggered colonic systemic inflammation. The bacterial taxa Prevotella sp. P4-67, Prevotella sp. PINT, and Bacteroides sp. CAG:927, together with fungal taxa Fusarium vanettenii, Neocallimastix californiae, Fusarium sp. AF-8, Hypoxylon sp. EC38, and Fusarium pseudograminearum, and the involved microbial immune pathways including the "T cell receptor signaling pathway" were higher in the colon of HES goats. The integrated metagenome and host transcriptome analysis revealed that these taxa were associated with enhanced pathogenic ability, antigen processing and presentation, and stimulated T helper 2 cell (TH2)-mediated cytokine secretion functions in the colon of HES goats. Further luminal metabolomics analysis showed increased relative content of chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA), and decreased the relative content of hypoxanthine in colonic digesta of HES goats. These altered metabolites contributed to enhancing the expression of TH2-mediated inflammatory-related cytokine secretion including GATA Binding Protein 3 (GATA3), IL-5, and IL-13. Using the linear mixed effect model, the variation of MUC2 biosynthesis explained by the colonic bacteria, bacterial functions, fungi, fungal functions, and metabolites were 21.92, 20.76, 19.43, 12.08, and 44.22%, respectively. The variation of pathology scores explained by the colonic bacterial functions, fungal functions, and metabolites were 15.35, 17.61, and 57.06%. CONCLUSIONS: Our findings revealed that enteral starch overload can trigger interrupted hindgut host-microbiome homeostasis that led to impaired mucosal, destroyed colonic water absorption, and TH2-mediated inflammatory process. Except for the colonic metabolites mostly contribute to the impaired mucosa, the nonnegligible contribution from fungi deserves more future studies focused on the fungal functions in hindgut dysbiosis of young ruminants. Video Abstract.

Simultaneous removal of PCDD/Fs and mercury by activated carbon from a full-scale MSW incinerator in southeast China.

This study emphasized on the removal performance of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and mercury by different activated carbon injection (ACI) rates from a full-scale (700 t/d) MSW incinerator. The result exhibited that the emission standard of PCDD/Fs and mercury could be met when the ACI rate reached 50 mg/Nm3 and 30 mg/Nm3, respectively. Lower chlorinated PCDD/Fs and PCDFs showed higher removal efficiencies compared with highly chlorinated PCDD/Fs and PCDDs, which could be attributed to the larger competitiveness of highly volatile congeners in AC adsorption than the lower volatile ones. AC turned out to have different adsorption selectivity for CP-routes PCDD/Fs congeners, among which 1379-TCDD was preferred to be absorbed while others exhibited little or poor selectivity for AC adsorption. The removal efficiency of PCDD/Fs was positively correlated with ACI rate at 99% confidence interval with a linear relationship (R2 = 0.98). Also, the outlet concentration of mercury decreased with the increase of ACI rate in a nearly linear function (R2 = 0.96). These results will be meaningful for the rational use of AC for pollutants control.

Real-time monitoring of ruminal microbiota reveals their roles in dairy goats during subacute ruminal acidosis.

Ruminal microbiota changes frequently with high grain diets and the occurrence of subacute ruminal acidosis (SARA). A grain-induced goat model of SARA, with durations of a significant decrease in the rumen pH value to less than 5.6 and an increase in the rumen lipopolysaccharides concentration, is constructed for real-time monitoring of bacteria alteration. Using 16 S rRNA gene sequencing, significant bacterial differences between goats from the SARA and healthy groups are identified at every hour for six continuous hours after feeding. Moreover, 29 common differential genera between two groups over 6 h after feeding are all related to the altered pH and lipopolysaccharides. Transplanting the microbiota from donor goats with SARA could induce colonic inflammation in antibiotic-pretreated mice. Overall, significant differences in the bacterial community and rumen fermentation pattern between the healthy and SARA dairy goats are real-time monitored, and then tested using ruminal microbe transplantation to antibiotic-treated mice.

Formation and inhibition of Polychlorinated-ρ-dibenzodioxins and dibenzofurans from mechanical grate municipal solid waste incineration systems.

This study is carried out in two full-scale (300 t/d) municipal solid waste incinerators (MSWI), focusing on the inhibition effect on polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/F) formation by the Sulfur-, Phosphorus-, and Nitrogen-containing inhibitors. The inhibition efficiencies of total PCDD/F range from 45.77 % to 58.55 %, meanwhile, from 50.1 % to 57.6 % for toxic PCDD/F. X-ray photoelectron spectroscopy results conduct the inhibition effect on the three key factors of PCDD/F formation: catalytic metal, carbon source and chlorine source. Inhibitors can increase the proportion of inorganic chlorine form at the ash surface. The changes of sulfur and phosphorus forms support the inhibition mechanisms of PCDD/F. De novo synthesis is the stable inhibition pathway in this study, meanwhile, the chlorophenols-route and dibenzodioxin and dibenzofuran chlorination also work in some tests. The results are the basics for further industrial application of PCDD/F inhibitors and benefit in controlling the PCDD/F emission from MSWI.

Inhibition of polychlorinated dibenzo-p-dioxins and dibenzofurans by phosphorus-containing compounds in model fly ash.

Waste incineration is a preferred method in China to dispose the municipal solid waste, but controlling the production of highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans effectively during incineration is both challenging and imperative. In this study, the suppression of PCDD/Fs by various phosphorus-containing compounds was explored, and the mechanisms responsible for the inhibition were studied in detail. The experiments took place in a lab-scale vertical tubular reactor at 350 °C under a simulated flue gas (12 vol% O2 in N2 flow), and both the off-gases and residues were collected for PCDD/Fs analysis. The scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize the reaction residues. The experimental results revealed that NH4H2PO4 and (NH4)2·HPO4 showed the highest inhibitory effect (57.2% and 57.3%, respectively) on the PCDD/Fs formation, followed by CaHPO4 with inhibition efficiency of 39.1%. In contrast, KH2PO4 and K2HPO4 barely inhibited the generation of the PCDD/Fs. The inhibitory effect of NH4H2PO4 and (NH4)2·HPO4 was similar to that of nitrogen-based inhibitors. At the same time, it was proven that the inhibitory activity of CaHPO4 might be due to the reaction of it with Cu2+ forming stable compounds.

Changed Caecal Microbiota and Fermentation Contribute to the Beneficial Effects of Early Weaning with Alfalfa Hay, Starter Feed, and Milk Replacer on the Growth and Organ Development of Yak Calves.

This study aimed to investigate the effect of early weaning by supplying calves with alfalfa hay, starter feed, and milk replacer on caecal bacterial communities and on the growth of pre-weaned yak calves. Ten 30-day-old male yak calves were randomly assigned to 2 groups. The maternal grazing (MG) group was maternally nursed and grazed, and the early weaning (EW) group was supplied milk replacer, starter feed, and alfalfa hay twice per day. Compared with the yak calves in the MG group, the yak calves in the EW group showed significantly increased body weight, body height, body length, and chest girth. When suffering to the potential mechanism of improved growth of yak calves, except for the enhanced ruminal fermentation, the significantly increased total volatile fatty acids, propionate, butyrate, isobutyrate, and valerate in the caecum in the EW group could also serve to promote the growth of calves. By using 16S rDNA sequencing, some significantly increased caecal phylum and genera, which were all related to the enhanced caecal fermentation by utilizing both the fibrous and non-fibrous carbohydrates, were identified in the EW group. In conclusion, early weaning of yak calves by supplying them with alfalfa hay, starter feed, and milk replacer is more beneficial to the growth of yak calves when compared with maternal grazing and nursing, in part due to alterations in caecal microbiota and fermentation.

Detection method optimization, content analysis and stability exploration of natamycin in wine.

A new detection method of natamycin via HPLC-MS/MS was developed that uses an Agilent 6460 HPLC-MS/MS instrument and an Agilent RP18 (2.1mm×50mm, 1.8µm); the LOD was 1µg/L, the LOQ was 3.34µg/L, the recovery was 70-94%, the RSD was approximately 2-4%, and the total run time was 5min. In the new detection method of natamycin via HPLC-MS/MS, processing of the sample before detection is necessary, which can be performed using solid phase extraction. Surprisingly, natamycin was not detected in any the sampled retail commercial wines from the Chinese market. Natamycin is very unstable in wine because many process steps, including the malo-lactic fermentation, clarification and storage, could result in degradation of natamycin. Regarding the clarifying agents, bentonite exhibited the strongest effect on natamycin. During the storage period, natamycin is very sensitive to light.

Modified QuEChERS method combined with ultra-high performance liquid chromatography tandem mass spectrometry for the simultaneous determination of 26 mycotoxins in sesame butter.

A high-throughput method for the simultaneous determination of 26 mycotoxins in sesame butter was developed by coupling the modified Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method with ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-MS/MS). The samples were sequentially extracted using 20 mL (80:20, v/v) and 5 mL (20:80, v/v) acetonitrile aqueous solutions, followed by salting out by the addition of magnesium sulfate and sodium chloride. Finally, the samples were purified using hexane and dispersed C18 solid phase extraction (dSPE). The mycotoxins were further separated using a C18 column and detected by electrospray ionization (ESI) in the multiple reactions monitoring (MRM) mode. Using this detection technique, 16 mycotoxins were detected as positive ions using methanol and water containing 0.1% formic acid as the mobile phase, whereas the other 10 mycotoxins were detected as negative ions using methanol and water as the mobile phase. With the matrix-matched quantification calibration, the developed method showed a good linear dynamic range with regression coefficients of 0.995 or higher. This method allowed for the detection of the 26 mycotoxins at LOQs significantly lower than the available maximum residue levels currently regulated by EU regulations. Additionally, at the three spiking levels examined, the majority of recoveries were within 60-120%, with RSDs within 15%. The method developed herein has the advantages of high sensitivity, accuracy and throughput, and it can be applied to the target screening of mycotoxins in real samples.

[Determination of three azaspiracids in edible shellfishes by QuEChERS method combined with ultra high performance liquid chromatography-tandem mass spectrometry].

An ultra high performance liquid chromatography-tandem mass spectrometric method (UHPLC-MS/MS) was developed for the simultaneous determination of three natural forms of azaspiracids (AZA-1, AZA-2 and AZA-3) in edible shellfishes such as mussels, oysters, clams and scallops. The samples were homogeneously extracted with acetonitrile-water (85: 15, v/v). The resultant supernatants were purified with QuEChERS method and filtrated by 0.2 microm microporous filters. The separation was performed on an Agilent ZORBAX Eclipse Plus C18 column (100 mm x 2.1 mm, 1.8 microm) with the gradient elution using acetonitrile/water (containing 5 mmol/L ammonium acetate and 0.1% formic acid) as mobile phases. The three azaspiracids were detected using positive electrospray ionization (ESI +) followed with multiple reaction monitoring (MRM), and quantified by external standard calibration method. The calibration curves showed good linearity in the range of 1-100 microg/kg with the correlation coefficients (r2) greater than 0.995. The limits of quantification (LOQ, S/N = 10) were 1.0 microg/kg for all the three AZAs. The average recoveries of azaspiracids spiked in the matrix at the levels of 10, 20 and 50 microg/kg ranged from 71% to 108%. The relative standard deviations (RSDs) of inter-day and intra-day determinations were less than 10% (n = 6). The samples from several areas within and outside of China were screened, and some of the samples showed positive for azaspiracids. The developed method is easy to operate, very reproducible, sensitive, and efficient. It can be applied to the determination of the three forms of AZAs in the edible shellfishes as well shellfish products.