Viscosity of Ionic Liquids: Theories and Models.

Ionic liquids (ILs) offer a wide range of promising applications due to their unique and designable properties compared to conventional solvents. Further development and application of ILs require correlating/predicting their pressure-viscosity-temperature behavior. In this review, we firstly introduce methods for calculation of thermodynamic inputs of viscosity models. Next, we introduce theories, theoretical and semi-empirical models coupling various theories with EoSs or activity coefficient models, and empirical and phenomenological models for viscosity of pure ILs and IL-related mixtures. Our modelling description is followed immediately by model application and performance. Then, we propose simple predictive equations for viscosity of IL-related mixtures and systematically compare performances of the above-mentioned theories and models. In concluding remarks, we recommend robust predictive models for viscosity at atmospheric pressure as well as proper and consistent theories and models for P-η-T behavior. The work that still remains to be done to obtain the desired theories and models for viscosity of ILs and IL-related mixtures is also presented. The present review is structured from pure ILs to IL-related mixtures and aims to summarize and quantitatively discuss the recent advances in theoretical and empirical modelling of viscosity of ILs and IL-related mixtures.

Prediction Model for Postoperative Pressure Injury in Patients with Acute Type A Aortic Dissection.

OBJECTIVE: To establish a risk assessment model to predict postoperative National Pressure Injury Advisory Panel stage 2 or higher pressure injury (PI) risk in patients undergoing acute type A aortic dissection surgery. METHODS: This retrospective assessment included consecutive patients undergoing acute type A aortic dissection surgery in the authors' hospital from September 2017 to June 2021. The authors used LASSO (logistic least absolute shrinkage and selection operator) regression analysis to identify the most relevant variables associated with PI by running cyclic coordinate descent with 10-times cross-validation. The variables selected by LASSO regression analysis were subjected to multivariate logistic analysis. A calibration plot, receiver operating characteristic curve, and decision curve analysis were used to validate the model. RESULTS: There were 469 patients in the study, including 94 (27.5%) with postoperative PI. Ten variables were selected from LASSO regression: body mass index, diabetes, Marfan syndrome, stroke, preoperative skin moisture, hemoglobin, albumin, serum creatinine, platelet, and d-dimer. Four risk factors emerged after multivariate logistic regression: Marfan syndrome, preoperative skin moisture, albumin, and serum creatinine. The area under the receiver operating characteristic curve of the model was 0.765. The calibration plot and the decision curve analysis both suggested that the model was suitable for predicting postoperative PI. CONCLUSIONS: This study built an efficient predictive model that could help identify high-risk patients.

π-Diamond: A Diamondoid Superstructure Driven by π-Interactions.

Modulating the arrangement of superstructures through noncovalent interactions has a significant impact on macroscopic shape and the expression of unique properties. Constructing π-interaction-driven hierarchical three-dimensional (3D) superstructures poses challenges on account of limited directional control and weak intermolecular interactions. Here we report the construction of a 3D diamondoid superstructure, named π-Diamond, employing a ditopic strained Z-shaped building block comprising a porphyrin unit as bow-limb double-strapped with two m-xylylene units as bowstring. This superstructure, reminiscent of diamond's tetrahedral carbon composition, is composed of double-walled tetrahedron (DWT) driven solely by π-interactions. Hetero-π-stacking between porphyrin and m-xylylene panels drive the assembly of four building blocks predominantly into a DWT, which undergoes extension to create an adamantane unit and eventually a diamondoid superstructure wherein each porphyrin panel is shared by two neighboring tetrahedra through hetero-π-stacking. π-Diamond exhibits a solid-state fluorescent quantum yield 44 times higher than that of tetraphenylporphyrin along with excellent photocatalytic performance. The precise 3D directionality of π-interactions, achieved through strained multipanel building blocks, revolutionizes the assembly of hierarchical 3D superstructures driven by π-interactions.

Citrate-Based Polyester Elastomer with Artificially Regulatable Degradation Rate on Demand.

Citrate-based polymers are commonly used to create biodegradable implants. In an era of personalized medicine, it is highly desired that the degradation rates of citrate-based implants can be artificially regulated as required during clinical applications. Unfortunately, current citrate-based polymers only undergo passive degradation, which follows a specific degradation profile. This presents a considerable challenge for the use of citrate-based implants. To address this, a novel citrate-based polyester elastomer (POCSS) with artificially regulatable degradation rate is developed by incorporating disulfide bonds (S-S) into the backbone chains of the crosslinking network of poly(octamethylene citrate) (POC). This POCSS exhibits excellent and tunable mechanical properties, notable antibacterial properties, good biocompatibility, and low biotoxicity of its degradation products. The degradation rate of the POCSS can be regulated by breaking the S-S in its crosslinking network using glutathione (GSH). After a period of subcutaneous implantation of POCSS scaffolds in mice, the degradation rate eventually increased by 2.46 times through the subcutaneous administration of GSH. Notably, we observed no significant adverse effects on its surrounding tissues, the balance of the physiological environment, major organs, and the health status of the mice during degradation.

MiR-5189-3p Suppresses cell Proliferation, Invasion and Migration Through Targeting EIF5A2 in Laryngeal Squamous Cell Carcinoma.

A growing body of evidence suggests that miR-5189-3p plays a critical role in multiple diseases. This study aimed to investigate the function of miR-5189-3p in laryngeal squamous cell carcinoma (LSCC) and explore its underlying mechanisms. qRT-PCR was designed to determine the expression levels of miR-5189-3p and eukaryotic translation initiation factor 5A2 (EIF5A2), while CCK-8 assay was performed to measure the effects of miR-5189-3p on cell proliferation. Transwell assay was performed to evaluate cell invasion as well as migration, and wound healing assay was applied to demonstrate cell migratory ability. Target gene prediction and luciferase reporter assay were developed to screen the possible target gene of miR-5189-3p, and Western blot was designed to measure EIF5A2 protein expression. MiR-5189-3p was down-regulated in LSCC tissues and cell lines. Up-regulation of miR-5189-3p notably inhibited cell proliferation, invasion, and migration in HEP2 and FADU cells. EIF5A2 was the potential downstream gene of miR-5189-3p, and overexpression of miR-5189-3p apparently reduced EIF5A2 expression. Moreover, reintroduction of EIF5A2 rescued the tumor suppressive effects of miR-5189-3p. MiR-5189-3p functions as a tumor inhibitor in LSCC progression via directly regulating EIF5A2 and may be a potential therapeutic target for LSCC.

Mulberry leaf extract improves intestinal barrier function and displays beneficial effects on colonic microbiota and microbial metabolism in weaned piglets.

BACKGROUND: Mulberry leaf extract (MLE) extracted from mulberry leaves is rich in a variety of bioactive ingredients and can be used as feed additives of weaned piglets. The present study was conducted to evaluate the effects of dietary MLE supplementation on intestinal barrier function, colon microbial numbers and microbial metabolites of weaned piglets. RESULTS: MLE supplementation increased the villus height and the villus height/crypt depth ratio in jejunum and ileum (P < 0.05), increased the mRNA expression of ZO-1, Claudin-1 and MUC-2 in the ileal mucosa (P < 0.05), and decreased the serum level of lipopolysaccharide (P < 0.01). Meanwhile, MLE reduced the mRNA expression of tumor necrosis factor-α and interleukin-1ß (P < 0.05) and increased secretory immunoglobulin A level in the ileal mucosa (P < 0.05). In addition, MLE increased the numbers of beneficial bacteria Bifidobacterium and Lactobacillus (P < 0.05) and decreased the number of potential pathogenic bacteria Escherichia coli (P < 0.05) in the colon. Correspondingly, MLE supplementation reduced the pH value of colonic digesta (P < 0.05) and altered the microbial fermentation pattern of the colon by increasing the concentrations of microbial metabolites derived from carbohydrates fermentation such as lactate, acetate, butyrate and total short-chain fatty acids (P < 0.05), and decreasing the concentrations of microbial metabolites derived from amino acid fermentation such as p-cresol, skatole, spermine, histamine and tryptamine (P < 0.05). CONCLUSION: MLE supplementation improved intestinal barrier function and displayed beneficial effects on colon microbes and microbial metabolism in weaned piglets. © 2022 Society of Chemical Industry.

Cyclization of an Achiral Flipping Panel to Homochiral Tubes Exhibiting Circularly Polarized Luminescence.

Macrocyclization of the bendable 2,7-dimethoxythianthrene with methylene linkages afforded a pair of homochiral macrocycles featuring a hex-nut-like geometry. Their structures were fully characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction analysis. Their stable planar chirality facilitates efficient resolution of the pair of enantiomers which could be readily derivatized. Installing phenylethynyl groups on their rims leads to luminescent tubular macrocycles exhibiting circularly polarized luminescence with a large dissymmetry value |glum | of 5×10-3 . Supramolecular binding of electron-deficient guests by the tube results in fluorescence quenching, which proved its potential for the future development of switchable chiroptical systems.

Strain-Driven Formal [1,3]-Aryl Shift within Molecular Bows.

Delving into the influence of strain on organic reactions in small molecules at the molecular level can unveil valuable insight into developing innovative synthetic strategies and structuring molecules with superior properties. Herein, we present a molecular-strain engineering approach to facilitate the consecutive [1,2]-aryl shift (formal [1,3]-aryl shift) in molecular bows (MBs) that integrate 1,4-dimethoxy-2,5-cyclohexadiene moieties. By introducing ring strain into MBs through tethering the bow limb, we can harness the intrinsic mechanical forces to drive multistep aryl shifts from the para- to the meta- to the ortho-position. Through the use of precise intramolecular strain, the seemingly impractical [1,3]-aryl shift was realized, resulting in the formation of ortho-disubstituted products. The solvent and temperature play a crucial role in the occurrence of the [1,3]-aryl shift. The free energy calculations with inclusion of solvation support a feasible mechanism, which entails multistep carbocation rearrangements, for the formal [1,3]-aryl shift. By exploring the application of molecular strain in synthetic chemistry, this research offers a promising direction for developing new tools and strategies towards precision organic synthesis.

Cascade Synthesis of Benzotriazulene with Three Embedded Azulene Units and Large Stokes Shifts.

We report here the one-pot synthesis of benzo[1,2-a : 3,4-a' : 5,6-a'']triazulene (BTA), wherein three azulene units are embedded through a tandem reaction comprising two steps, Suzuki coupling and Knoevenagel condensation, between a readily available triborylated truxene precursor and 8-bromo-1-naphthaldehyde. Its nitration leads to a regioselective trinitrated product, namely, BTA-NO2 . Single-crystal X-ray crystallography revealed that the superstructure of BTA consists of a dimer stacked by two enantiomeric helicene conformers, while that of BTA-NO2 consists of an unprecedented π-tetramer stacked from two enantiomeric dimers, that is, four distinct helicene conformers. Both compounds show excellent stability and fluorescence with large Stokes shifts of up to 5100 cm-1 . In addition, BTA-NO2 exhibits a unique solvatochromic effect in different solvents and hydrogen-bonding-induced emission transfer in different ratios of THF/H2 O solutions.

Infinite Twisted Polycatenanes.

Poly[n]catenanes have exceptional mechanical bonding properties that give them tremendous potential for use in the development of molecular machines and soft materials. Synthesizing these compounds has, however, proven to be a formidable challenge. Herein, we describe a concise method for the construction of twisted polycatenanes. Our approach involves using preorganized double helicates as templates, linked crosswise in a linear fashion by either silver ions or triple bonds. By using this approach, we successfully synthesized twisted polycatenanes with both coordination and covalent bonding employing Ag(I) ions and ethynylene units, respectively, as the linkages and leveraging the same Ag(I)-templated double helicate in both cases. Synthesis with Ag(I) ions formed a single-crystalline one-dimensional (1D) coordination poly[n]catenane, and synthesis using ethynylene units generated 1D fibers which self-assembled with solvents to form a gel. Our results confirm the potential of multi-stranded metallohelicates for creating sophisticated mechanically interlocked molecules and polymers, which could pave the way for exploration in the realms of molecular nanotopology and materials design.

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation.

As a biodegradable elastomer, poly(1,8-octanediol-co-citrate) (POC) has been widely applied in tissue engineering and implantable electronics. However, the unclear degradation mechanism has posed a great challenge for the better application and development of POC. To reveal the degradation mechanism, here, we present a systematic investigation into in vivo and in vitro degradation behaviors of POC. Initially, critical factors, including chemical structures, hydrophilic and water-absorbency characteristics, and degradation reaction of POC, are investigated. Then, various degradation-induced changes during in vitro degradation of POC-x (POC with different cross-linking densities) are monitored and discussed. The results show that (1) cross-linking densities exponentially drop with degradation time; (2) mass loss and PBS-absorption ratio grow nonlinearly; (3) the morphology on the cross-section changes from flat to rough at a microscopic level; (4) the cubic samples keep swelling until they collapse into fragments from a macro view; and (5) the mechanical properties experience a sharp drop at the beginning of degradation. Finally, the in vivo degradation behaviors of POC-x are investigated, and the results are similar to those in vitro. The comprehensive assessment suggests that the in vitro and in vivo degradation of POC occurs primarily through bulk erosion. Inflammation responses triggered by the degradation of POC-x are comparable to poly(lactic acid), or even less obvious. In addition, the mechanical evaluation of POC in the simulated application environment is first proposed and conducted in this work for a more appropriate application. The degradation mechanism of POC revealed will greatly promote the further development and application of POC-based materials in the biomedical field.

Exogenous Glutathione Protects IPEC-J2 Cells against Oxidative Stress through a Mitochondrial Mechanism.

The accumulation of reactive oxygen species (ROS) triggers oxidative stress in cells by oxidizing and modifying various cellular components, preventing them from performing their inherent functions, ultimately leading to apoptosis and autophagy. Glutathione (GSH) is a ubiquitous intracellular peptide with multiple functions. In this study, a hydrogen peroxide (H2O2)-induced oxidative damage model in IPEC-J2 cells was used to investigate the cellular protection mechanism of exogenous GSH against oxidative stress. The results showed that GSH supplement improved the cell viability reduced by H2O2-induced oxidative damage model in IPEC-J2 cells in a dose-dependent manner. Moreover, supplement with GSH also attenuated the H2O2-induced MMP loss, and effectively decreased the H2O2-induced mitochondrial dysfunction by increasing the content of mtDNA and upregulating the expression TFAM. Exogenous GSH treatment significantly decreased the ROS and MDA levels, improved SOD activity in H2O2-treated cells and reduced H2O2-induced early apoptosis in IPEC-J2 cells. This study showed that exogenous GSH can protect IPEC-J2 cells against apoptosis induced by oxidative stress through mitochondrial mechanisms.

Effects of dietary citrus extract on growth performance, carcass characteristics and meat quality of pigs.

This study investigated the effects of citrus extract on growth, carcass and meat quality of Duroc × Landrace × Large White pigs. One hundred and eight pigs (54 barrows, 54 females) were assigned to one of three dietary treatments for 138 days. The dietary treatments were (1) basic diet; (2) basic diet supplemented with 75 mg/kg chlortetracycline; and (3) basic diet supplemented with citrus extract (0.25 ml/kg during 56-112 days of age and 0.20 ml/kg during 113-194 days of age). No significant differences among treatments were found for growth performance, carcass characteristics, meat quality and free amino acids (p > 0.05). Feeding citrus extract tended to increase intramuscular fat (p = 0.052). Citrus extract and chlortetracycline increased C15:0 concentration (p = 0.016) and superoxide dismutase activity (p = 0.004). The pigs that received chlortetracycline exhibited the lowest (p = 0.033) muscle malondialdehyde concentration. Overall, citrus extract ameliorated some meat quality indicators without adverse effects on pig growth or carcass performance.

Linear Nonalternant Isomers of Acenes Fusing Multiple Azulene Units.

A modular approach to azulene building blocks was developed starting from readily available aryl-substituted cyclopentadiene and ortho-haloaryl aldehyde by dehydration condensation followed by palladium-catalyzed C-H coupling. It facilitates the synthesis of four nonalternant isomers of pentacene and hexacene, namely, dibenzo[e,g]azulene, benzo[1,2-f : 5,4-f']diazulene, benzo[1,2-f : 4,5-f']diazulene, and naphtho[2,3-f : 6,7-f']diazulene, which exhibit narrow band gaps with high stability in addition to protonation-caused enhanced near-infrared fluorescence. We discovered that in these isomers, i) constitutional isomerism influences significantly their photoelectric properties and ii) the elongation of the conjugation system does not necessarily lead to a narrowing in the band gap. Due to the easy modifiability of the nonazulene building blocks, this strategy can be extended to modularly prepare numerous multiazulene-fused aromatics.

TetrazineBox: A Structurally Transformative Toolbox.

Synthetic macrocycles capable of undergoing allosteric regulation by responding to versatile external stimuli are the subject of increasing attention in supramolecular science. Herein, we report a structurally transformative tetracationic cyclophane containing two 3,6-bis(4-pyridyl)-l,2,4,5-tetrazine (4-bptz) units, which are linked together by two p-xylylene bridges. The cyclophane, which possesses modular redox states and structural post-modifications, can undergo two reversibly consecutive two-electron reductions, affording first its bisradical dicationic counterpart, and then subsequently the fully reduced species. Furthermore, one single-parent cyclophane can afford effectively three other new analogs through box-to-box cascade transformations, taking advantage of either reductions or an inverse electron-demand Diels-Alder (IEDDA) reaction. While all four new tetracationic cyclophanes adopt rigid and symmetric box-like conformations, their geometries in relation to size, shape, electronic properties, and binding affinities toward polycyclic aromatic hydrocarbons can be readily regulated. This structurally transformative tetracationic cyclophane performs a variety of new tasks as a result of structural post-modifications, thus serving as a toolbox for probing the radical properties and generating rapidly a range of structurally diverse cyclophanes by efficient divergent syntheses. This research lays a solid foundation for the introduction of the structurally transformative tetracationic cyclophane into the realm of mechanically interlocked molecules and will provide a toolbox to construct and operate intelligent molecular machines.

Highly Stable Organic Bisradicals Protected by Mechanical Bonds.

Two new highly charged [2]catenanes-namely, mHe[2]C·6PF6 and mHo[2]C·6PF6-were synthesized by exploiting radical host-guest templation between derivatives containing BIPY•+ radical cations and the meta analogue of cyclobis(paraquat-p-phenylene). In contrast to related [2]catenanes that have been isolated as air-stable monoradicals, both mHe[2]C·6PF6 and mHo[2]C·6PF6 exist as air-stable singlet bisradicals, as evidenced by both X-ray crystallography in the solid state and EPR spectroscopy in solution. Electrochemical studies indicate that the first two reduction peaks of these two [2]catenanes are shifted significantly to more positive potentials, a feature which is responsible for their extraordinary stability in air. The mixed-valence nature of the mono- and bisradical states endows them with unique NIR absorption properties, e.g., NIR absorption bands for the mono- and bisradical states observed at ∼1800 and ∼1450 nm, respectively. These [2]catenanes are potentially useful in applications that include NIR photothermal conversion, UV-vis-NIR multiple-state electrochromic materials, and multiple-state memory devices. Our findings highlight the principle of "mechanical-bond-induced stabilization" as an efficient strategy for designing persistent organic radicals.

Organic Counteranion Co-assembly Strategy for the Formation of γ-Cyclodextrin-Containing Hybrid Frameworks.

A class of γ-cyclodextrin-containing hybrid frameworks (CD-HFs) has been synthesized, employing γ-cyclodextrin (γ-CD) as the primary building blocks, along with 4-methoxysalicylate (4-MS-) anions as the secondary building blocks. CD-HFs are constructed through the synergistic exploitation of coordinative, electrostatic, and dispersive forces. The syntheses have been carried out using an organic counteranion co-assembly strategy, which allows for the introduction of 4-MS-, in place of inorganic OH-, into the cationic γ-CD-containing metal-organic frameworks (CD-MOFs). Although the packing arrangement of the γ-CD tori in the solid-state superstructure of CD-HFs is identical to that of the previously reported CD-MOFs, CD-HFs crystallize with lower symmetry and in the cuboid space group P43212-when compared to CD-MOF-1, which has the cubic unit cell of I432 space group-on account of the chiral packing of the 4-MS- anions in the CD-HF superstructures. Importantly, CD-HFs have ultramicroporous apertures associated with the pore channels, a significant deviation from CD-MOF-1, as a consequence of the contribution from the 4-MS- anions, which serve as supramolecular baffles. In gas adsorption-desorption experiments, CD-HF-1 exhibits a Brunauer-Emmett-Teller (BET) surface area of 306 m2 g-1 for CO2 at 195 K, yet does not uptake N2 at 77 K, confirming the difference in porosity between CD-HF-1 and CD-MOF-1. Furthermore, the 4-MS- anions in CD-HF-1 can be exchanged with OH- anions, leading to an irreversible single-crystal to single-crystal transformation, with rearrangement of coordinated metal ions. Reversible transformations were also observed in CD-MOF-1 when OH- ions were exchanged for 4-MS- anions, with the space group changing from I432 to R32. This organic counteranion co-assembly strategy opens up new routes for the construction of hybrid frameworks, which are inaccessible by existing de novo MOF assembly methodologies.

Single-Crystal Polycationic Polymers Obtained by Single-Crystal-to-Single-Crystal Photopolymerization.

The efficient preparation of single-crystalline ionic polymers and fundamental understanding of their structure-property relationships at the molecular level remains a challenge in chemistry and materials science. Here, we describe the single-crystal structure of a highly ordered polycationic polymer (polyelectrolyte) and its proton conductivity. The polyelectrolyte single crystals can be prepared on a gram-scale in quantitative yield, by taking advantage of an ultraviolet/sunlight-induced topochemical polymerization, from a tricationic monomer-a self-complementary building block possessing a preorganized conformation. A single-crystal-to-single-crystal photopolymerization was revealed unambiguously by in situ single-crystal X-ray diffraction analysis, which was also employed to follow the progression of molecular structure from the monomer, to a partially polymerized intermediate, and, finally, to the polymer itself. Collinear polymer chains are held together tightly by multiple Coulombic interactions involving counterions to form two-dimensional lamellar sheets (1 nm in height) with sub-nanometer pores (5 Å). The polymer is extremely stable under 254 nm light irradiation and high temperature (above 500 K). The extraordinary mechanical strength and environmental stability-in combination with its impressive proton conductivity (∼3 × 10-4 S cm-1)-endow the polymer with potential applications as a robust proton-conducting material. By marrying supramolecular chemistry with macromolecular science, the outcome represents a major step toward the controlled synthesis of single-crystalline polyelectrolyte materials with perfect tacticity.

Selective Recovery and Detection of Gold with Cucurbit[n]urils (n = 5-7).

Environmentally benign methods for gold recovery and detection are highly desirable for a sustainable future. Herein, we demonstrate a selective recovery and detection strategy of gold with cucurbit[n]urils (Q[n = 5-7]) by means of outer-surface interactions. Tetrachloroaurate anion ([AuCl4]-) is able to be rapidly precipitated with Q[n] in forms of supramolecular adducts. X-ray crystallography of four Q[n = 5-7]·[AuCl4]- complexes reveal that strong outer-surface interactions between Q[n = 5-7] and [AuCl4]- are the major driving force for the formation of Q[n = 5-7]·[AuCl4]- complexes. Impressively, each Q[6] macrocycle is surrounded by 12 [AuCl4]- anions. Each of these 12 [AuCl4]- anions is connected to four adjacent [AuCl4]- anions, leading to the formation of a three-dimensional supramolecular framework with tubular channels. In addition, we found an interesting inclusion complex [Au(OH2)4]3+⊂Q[7] in the Q[7]·[AuCl4]- complex, which is the first example of hydrated metal cation encapsulated inside the cavity of Q[n]. Spectroscopic data suggest that Q[n = 5-7] possess a high affinity and selectivity for [AuCl4]- even in the presence of other transition-metal ions. Q[n] modified electrodes are found to be an effective material for the detection of trace gold in dilute solutions.

Dietary supplementation with citrus extract alters the plasma parameters, circulating amino acid profiles and gene expression of small intestinal nutrient transporters in Chinese yellow-feathered broilers.

BACKGROUND: This study evaluated the effects of citrus extract (CE) on growth performance, plasma amino acid (AA) profiles, intestinal development and small intestine AA and peptide transporter expression levels in broilers. A total of 540 one-day-old yellow-feathered broilers were fed a basal diet without any antibiotic (control group), or a basal diet containing 10 mg kg-1 zinc bacitracin (antibiotic group), or a basal diet supplemented with 10 mg kg-1 CE (CE group). After 63 days of feeding, two broilers per pen were slaughtered to collect tissues for further analysis. RESULTS: Results showed that CE increased (P < 0.05) the final body weight and average daily gain from day 1 to 63, and decreased (P < 0.05) the feed/gain ratio from day 1 to 63. Dietary CE supplementation increased (P < 0.05) plasma total protein, albumin and glucose concentration, and decreased (P < 0.05) urea concentration. CE supplementation increased (P < 0.05) the villus height in the ileum and the villus height/crypt depth in the jejunum and ileum, but decreased (P < 0.05) the crypt depth in the jejunum and ileum. CE supplementation increased (P < 0.05) most plasma essential AA concentrations. Additionally, CE supplementation upregulated (P < 0.05) ASCT1, b0,+ AT, B0 AT1, EAAT3, rBAT, y+ LAT2 and PepT1 expression in the jejunum, and b0,+ AT, EAAT3, rBAT, y+ LAT2, CAT1 and PepT1 in the ileum. CONCLUSIONS: Collectively, our results indicated that CE supplementation promotes intestinal physiological absorption of AAs by upregulating gene expression of small intestinal key AA and peptide transporters, thereby enhancing the growth performance of broilers. © 2020 Society of Chemical Industry.