Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

Background： This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter（AGP） on performance, immune status and gut structure after an E. coli lipopolysaccharide（LPS） challenge. Thirty-six pigs were allotted to six treatments including： a non-challenged control（NCC）; LPS-challenged control（CC）; CC ＋ AGP; CC ＋ yeast extract; CC ＋ enzymes; and CC ＋ enzymes ＋ yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples.Results： Overall（d 1 to 11）, compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG（P = 0.004）,ADFI（P = 0.03） and gain/feed ratio（P = 0.01）. At 6 h post-challenge, AGP pigs had lower plasma urea N（PUN; P = 0.02）and serum TNF-α concentration（P = 0.07）, and higher platelet count（P = 0.04） and serum IL-10 concentration（P = 0.02） than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN（P = 0.02） than CC pigs, whereas enzymes ＋ yeast extract interacted non-additively（P = 0.001） to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN（P = 0.02）and higher duodenal（P = 0.03）, jejunal（P = 0.01） and ileal（P = 0.07） villus height than CC pigs. In addition, enzymes ＋yeast extract interacted additively and non-additively to reduce ileal IFN-γ（P 0.10） were observed between AGP and enzymes ＋ yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ（P ＆lt; 0.0001） and TNF-α（P = 0.003） in enzymes ＋ yeast extract pigs at 96 h post-challenge.Conclusions： The LPS challenged piglets receiving enzymes ＋ yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.

ZIF-8 modified by isocyanate as a photocatalytic antibacterial agent

Zeolite imidazole skeleton(ZIF-8)is a promising option for self-cleaning of building exterior walls due to its large specific surface area,high antibacterial activity and low biotoxicity.However,it suffers from low antibacterial efficiency and yield under visible light irradiation.To address the issues,we developed the photocatalytic materials T-ZIF-8-TDI(thermally treated-ZIF-8-toluene 2,4-diisocyanate)by modifying ZIF-8 with thermal oxygen sensitization and chemical bonding.The results show that the yield of T-ZIF-8-TDI photocatalytic antibacterial agent is increased to 11.5 times of that of T-ZIF-8,while maintaining the crystal structure of T-ZIF-8 and thermal stability up to 60℃.Furthermore,T-ZIF-8-TDI exhibits extended optical response range to the nearinfrared region,significantly narrowed band gap,improved photogenerated elec tron-hole separation efficiency,reduced recombination rate,and excellent photocatalytic performance.When the concentration of antibacterial agent is 600 mg·L^(-1),the antibacterial rate of Escherichia coli(E.coli)reaches 99.99%irradiated by visible light for30 min,and when the concentration of antibacterial agent is 200 mg·L^(-1),the antibacterial rate of Staphylococcus aureus(S.aureus)reaches 99.99%irradiated by visible light for 25 min.We also analyzed the reasons in detail from the aspects of bacterial species and antibacterial mechanism,and proposed the antibacterial mechanism of·O_(2)^(-)and h^(+)as the main active species.These findings suggest that T-ZIF-8-TDI photocatalytic antibacterial agent has potential for use in self-cleaning of building exterior walls.

Biomimetic Modification of Super-wetting Electrospun Poly(vinylidene fluoride)Porous Fibers with Organic Dyes and Heavy Metal Ions Adsorption,Oil/Water Separation,and Sterilization Performances Toward Wastewater Treatment

Polymeric membranes with the integration of various functional performances toward wastewater treatment are urgently required.However,most of the polymeric membranes only exhibit a single function of highly efficiently removing one kind of pollutants.In this work,a biomimetic modification method was introduced to tailor the chemical and topological structure of the porous poly(vinylidene fluoride)(PVDF)fibers prepared by electrospinning.The polydopamine(PDA)nanoparticles were homogeneously introduced onto the surface of PVDF porous fibers via precisely tailoring the concentration of dopamine,which endowed the fibers with more polar groups and bigger roughness but did not destroy the crystalline structures.The fibrous membranes exhibited switchable superhydrophilicity and superlipophilicity characteristics,excellent adsorption abilities toward organic dyes,heavy metal ions and oils.The highest adsorption capacities achieved 917.4 mg/g toward methylene blue(MB),42.6 mg/g toward Cr(VI)and 74.6 g/g toward silicone oil,respectively.Specifically,the membrane could rapidly remove the trace MB when water flowed through the membrane.The membrane also exhibited excellent sterilization performances,and the bacterial eliminating rate achieved 99.9%for the E.coli and S.aureus.The excellent light-to-heat conversion ability endowed the membrane with the selfheating ability,furtherly intensifying the wastewater treatment efficiency.This work confirms that the PDA nanoparticles-decorated PVDF porous fibers might be the new generation adsorbents used in wastewater treatment.

Effect of Cu Addition in Pipeline Steels on Microstructure,Mechanical Properties and Microbiologically Influenced Corrosion

In the present study, Cu-modified pipeline steels were fabricated to mitigate MIC by the antimicrobial ability of Cu element. The microstructure, mechanical properties and the antimircobial performance of the Cu-modified steel were systematically investigated. The Cu-modified steels showed good antimicrobial performance with remarkable strength enhancement by nanoscale Cu-rich precipitates and good impact toughness without changing the original base microstructures after the optimal aging treatment of 500 °C/1 h.