Fasting-Induced Molting Impacts the Intestinal Health by Altering the Gut Microbiota.

Fasting-induced molting (FIM) is a common method used to improve the laying performance of aged laying hens. Nevertheless, this approach may impose various stresses on chickens, such as disruptions in intestinal flora and inflammation issues within the intestines. However, the impact of an imbalance in intestinal flora on intestinal health during the FIM process remains elusive. Therefore, intestinal injury, the microbiome, and the metabolome were analyzed individually and integrated to elucidate the impact of the intestinal flora on intestinal health during the FIM process. The findings indicated that fasting resulted in a notable reduction in villus height and villus/crypt ratio, coupled with elevated levels of intestinal inflammation and permeability. During the fasting period, microbiota compositions changed. The abundance of Escherichia_Shigella increased, while the abundance of Ruminococcaceae_UCG-013 and Lactobacillus decreased. Escherichia_Shigella was positively correlated with Citrinin and Sterobilin, which lead to intestinal inflammation. Ruminococcaceae_UCG-013 and Lactobacillus exhibited positive correlations with Lanthionine and reduced Glutathione, thereby reducing intestinal inflammation. This study screened the intestinal probiotics, Ruminococcaceae UCG-013 and Lactobacillus, that influence gut health during the fasting period, providing an experimental basis for improving gut microbiota and reducing intestinal inflammation during the FIM process.

Functional Characterization of the Soybean Glycine max Actin Depolymerization Factor GmADF13 for Plant Resistance to Drought Stress.

Abiotic stress significantly affects plant growth and has devastating effects on crop production. Drought stress is one of the main abiotic stressors. Actin is a major component of the cytoskeleton, and actin-depolymerizing factors (ADFs) are conserved actin-binding proteins in eukaryotes that play critical roles in plant responses to various stresses. In this study, we found that GmADF13, an ADF gene from the soybean Glycine max, showed drastic upregulation under drought stress. Subcellular localization experiments in tobacco epidermal cells and tobacco protoplasts showed that GmADF13 was localized in the nucleus and cytoplasm. We characterized its biological function in transgenic Arabidopsis and hairy root composite soybean plants. Arabidopsis plants transformed with GmADF13 displayed a more robust drought tolerance than wild-type plants, including having a higher seed germination rate, longer roots, and healthy leaves under drought conditions. Similarly, GmADF13-overexpressing (OE) soybean plants generated via the Agrobacterium rhizogenes-mediated transformation of the hairy roots showed an improved drought tolerance. Leaves from OE plants showed higher relative water, chlorophyll, and proline contents, had a higher antioxidant enzyme activity, and had decreased malondialdehyde, hydrogen peroxide, and superoxide anion levels compared to those of control plants. Furthermore, under drought stress, GmADF13 OE activated the transcription of several drought-stress-related genes, such as GmbZIP1, GmDREB1A, GmDREB2, GmWRKY13, and GmANK114. Thus, GmADF13 is a positive regulator of the drought stress response, and it may play an essential role in plant growth under drought stress conditions. These results provide new insights into the functional elucidation of soybean ADFs. They may be helpful for breeding new soybean cultivars with a strong drought tolerance and further understanding how ADFs help plants adapt to abiotic stress.

Aggregation Enhanced Thermally Activated Delayed Fluorescence through Spin-Orbit Coupling Regulation.

Integrating aggregation-induced emission (AIE) into thermally activated delayed fluorescence (TADF) emitters holds great promise for the advancement of highly efficient organic light emitting diodes (OLEDs). Despite recent advancements, a thorough comprehension of the underlying mechanisms remains imperative for the practical application of such materials. In this work, we introduce a novel approach aimed at modulating the TADF process by manipulating dynamic processes in excited states through aggregation effect. Our findings reveal that aggregation not only enhances both prompt and delayed fluorescence simultaneously but also imposes constraints on molecular reorientation. This constraint reinforces spin-orbit coupling and reduces the energy gap between singlets and triplets. These insights deepen our understanding of the fundamental mechanisms governing the aggregation effect on TADF materials and provide valuable guidance for the design of high-efficiency photoluminescent materials.

Estrogen promotes gonadotropin-releasing hormone expression by regulating tachykinin 3 and prodynorphin systems in chicken.

The "KNDy neurons" located in the hypothalamic arcuate nucleus (ARC) of mammals are known to co-express kisspeptin, neurokinin B (NKB), and dynorphin (DYN), and have been identified as key mediators of the feedback regulation of steroid hormones on gonadotropin-releasing hormone (GnRH). However, in birds, the genes encoding kisspeptin and its receptor GPR54 are genomic lost, leaving unclear mechanisms for feedback regulation of GnRH by steroid hormones. Here, the genes tachykinin 3 (TAC3) and prodynorphin (PDYN) encoding chicken NKB and DYN neuropeptides were successfully cloned. Temporal expression profiling indicated that TAC3, PDYN and their receptor genes (TACR3, OPRK1) were mainly expressed in the hypothalamus, with significantly higher expression at 30W than at 15W. Furthermore, overexpression or interference of TAC3 and PDYN can regulate the GnRH mRNA expression. In addition, in vivo and in vitro assays showed that estrogen (E2) could promote the mRNA expression of TAC3, PDYN, and GnRH, as well as the secretion of GnRH/LH. Mechanistically, E2 could dimerize the nuclear estrogen receptor 1 (ESR1) to regulate the expression of TAC3 and PDYN, which promoted the mRNA and protein expression of GnRH gene as well as the secretion of GnRH. In conclusion, these results revealed that E2 could regulate the GnRH expression through TAC3 and PDYN systems, providing novel insights for reproductive regulation in chickens.

Coupling Nano and Atomic Electric Field Confinement for Robust Alkaline Oxygen Evolution.

The alkaline oxygen evolution reaction (OER) is a promising avenue for producing clean fuels and storing intermittent energy. However, challenges such as excessive OH- consumption and strong adsorption of oxygen-containing intermediates hinder the development of alkaline OER. In this study, we propose a cooperative strategy by leveraging both nano-scale and atomically local electric fields for alkaline OER, demonstrated through the synthesis of Mn single atom doped CoP nanoneedles (Mn SA-CoP NNs). Finite element method simulations and density functional theory calculations predict that the nano-scale local electric field enriches OH- around the catalyst surface, while the atomically local electric field improves *O desorption. Experimental validation using in situ attenuated total reflection infrared and Raman spectroscopy confirms the effectiveness of the nano-scale and atomically electric fields. Mn SA-CoP NNs exhibit an ultra-low overpotential of 189 mV at 10 mA cm-2 and stable operation over 100 hours at ~100 mA cm-2 during alkaline OER. This innovative strategy provides new insights for enhancing catalyst performance in energy conversion reactions.

Genome-wide identification and expression analysis of the KCS gene family in soybean (Glycine max) reveal their potential roles in response to abiotic stress.

Very long chain fatty acids (VLCFAs) are fatty acids with chain lengths of 20 or more carbon atoms, which are the building blocks of various lipids that regulate developmental processes and plant stress responses. 3-ketoacyl-CoA synthase encoded by the KCS gene is the key rate-limiting enzyme in VLCFA biosynthesis, but the KCS gene family in soybean (Glycine max) has not been adequately studied thus far. In this study, 31 KCS genes (namely GmKCS1 - GmKCS31) were identified in the soybean genome, which are unevenly distributed on 14 chromosomes. These GmKCS genes could be phylogenetically classified into seven groups. A total of 27 paralogous GmKCS gene pairs were identified with their Ka/Ks ratios indicating that they had undergone purifying selection during soybean genome expansion. Cis-acting element analysis revealed that GmKCS promoters contained multiple hormone- and stress-responsive elements, indicating that GmKCS gene expression levels may be regulated by various developmental and environmental stimuli. Expression profiles derived from RNA-seq data and qRT-PCR experiments indicated that GmKCS genes were diversely expressed in different organs/tissues, and many GmKCS genes were found to be differentially expressed in the leaves under cold, heat, salt, and drought stresses, suggesting their critical role in soybean resistance to abiotic stress. These results provide fundamental information about the soybean KCS genes and will aid in their further functional elucidation and exploitation.

Evaluation of stimbiotic on growth performance and intestinal development of broilers fed corn- or wheat-based diets.

In the antibiotics-free era, stimbiotic (STB) has been suggested as a new alternative of antibiotic growth promoters to modulate intestinal health via stimulating dietary fiber utilization in poultry production. The aim of this study was to evaluate the effects of STB supplementation in corn- or wheat-basal diet on growth performance, intestinal development, and function of broilers. A total of 512 one-day-old Arbor Acres(AA)broilers were randomly allocated 4 treatments, including corn group (CG), corn + 100 g/t STB (CG + STB), wheat group (WG), wheat + 100 g/t STB (WG + STB). The broilers were weighed at the days of 14, 28, and 42, of which 8 repetitions per treatment were randomly selected to determine the intestinal morphology, intestinal barrier, and cecal microbiota and metabolites. Our data showed that STB increased (P < 0.05) feed intake, body weight and reduced FCR for the overall period (0-42 d). At 28 d of age, significant increases in villus height and the villus height-to-crypt depth ratio (V/C) were found in the STB supplementation groups (P < 0.05). Addition of STB significantly increased intestinal mucosal DAO and AMPK enzyme activity and the gene expression of OCLN, CLDN1, ZO1, MUC2, SGLT1, PEPT1, FABP2, Ghrelin, and GCG in jejunum (P < 0.05), and significantly decreased the expression of the PYY gene. In addition, STB increased the relative abundance of beneficial bacteria, such as Akkermansia, Bifidobacterium, and Oscillospirales (P < 0.05). A significant increase in cecal short-chain fatty acid (SCFAs) concentration was also observed in the STB supplementation groups. At the cellular level, STB cannot directly increase the expression of small intestinal epithelial cells, and may indirectly improve intestinal barrier function by increasing the level of sodium butyrate. Overall, these results indicated that STB supplementation could improve the growth performance, intestinal development and barrier functions, and fiber fermentation in cecum of broiler chickens.

Research progress on the roles of actin-depolymerizing factor in plant stress responses.

Actin-depolymerizing factors (ADFs) are highly conserved small-molecule actin-binding proteins found throughout eukaryotic cells. In land plants, ADFs form a small gene family that displays functional redundancy despite variations among its individual members. ADF can bind to actin monomers or polymerized microfilaments and regulate dynamic changes in the cytoskeletal framework through specialized biochemical activities, such as severing, depolymerizing, and bundling. The involvement of ADFs in modulating the microfilaments' dynamic changes has significant implications for various physiological processes, including plant growth, development, and stress response. The current body of research has greatly advanced our comprehension of the involvement of ADFs in the regulation of plant responses to both biotic and abiotic stresses, particularly with respect to the molecular regulatory mechanisms that govern ADF activity during the transmission of stress signals. Stress has the capacity to directly modify the transcription levels of ADF genes, as well as indirectly regulate their expression through transcription factors such as MYB, C-repeat binding factors, ABF, and 14-3-3 proteins. Furthermore, apart from their role in regulating actin dynamics, ADFs possess the ability to modulate the stress response by influencing downstream genes associated with pathogen resistance and abiotic stress response. This paper provides a comprehensive overview of the current advancements in plant ADF gene research and suggests that the identification of plant ADF family genes across a broader spectrum, thorough analysis of ADF gene regulation in stress resistance of plants, and manipulation of ADF genes through genome-editing techniques to enhance plant stress resistance are crucial avenues for future investigation in this field.

Adiponectin inhibits GnRH secretion via activating AMPK and PI3K signaling pathways in chicken hypothalamic neuron cells.

It has been reported that adiponectin (AdipoQ), an adipokine secreted by white adipose tissue, plays an important role in the control of animal reproduction in addition to its function in energy homeostasis by binding to its receptors AdipoR1/2. However, the molecular mechanisms of AdipoQ in the regulation of animal reproduction remain elusive. In this study, we investigated the effects of AdipoQ on hypothalamic reproductive hormone (GnRH) secretion and reproduction-related receptor gene (estrogen receptor [ER] and progesterone receptor [PR]) expression in hypothalamic neuronal cells (HNCs) of chickens by using real-time fluorescent quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), Western blot (WB) and cell counting kit-8 (CCK-8) assays and found that overexpression of AdipoQ could increase the expression levels of AdipoR1/2 and reproduction-related receptor genes (P < 0.05) while decreasing the expression level of GnRH. In contrast, interference with AdipoQ mRNA showed the opposite results in HNCs. Furthermore, we demonstrated that AdipoQ exerts its functions through the AMPK and PI3K signaling pathways. Finally, our in vitro experiments found that AdipoRon (a synthetic substitute for AdipoQ) treatment and AdipoR1/2 RNAi interference co-treatment resulted in no effect on GnRH secretion, suggesting that the inhibition of GnRH secretion by AdipoQ is mediated by the AdipoR1/2 signaling axis. In summary, we uncovered, for the first time, the molecular mechanism of AdipoQ in the regulation of reproductive hormone secretion in hypothalamic neurons in chickens.

Identification of an Acinetobacter pittii acyltransferase involved in transformation of deoxynivalenol to 3-acetyl-deoxynivalenol by transcriptomic analysis.

Deoxynivalenol (DON), a mycotoxin primarily produced by Fusarium graminearum (F. graminearum), is widely present in food and feed, posing great hazards to human and livestock health. In this study, a strain of Acinetobacter pittii (A. pittii) S12 capable of degrading DON was isolated from soil samples and identified through morphological characterization, biochemistry analysis, and 16 S rRNA gene sequencing. The results of HPLC-MS indicated that the degradation products underwent a conversion from [M-H]- to [M+CH3CO], with concomitant transformation of the hydroxyl group into an acetyl moiety. Based on transcriptome sequencing analysis, the acyltransferase encoded by DLK06_RS13370 was predicted to be the pivotal gene responsible for DON biotransformation. The result of molecular docking analysis suggest a high affinity between the enzyme and DON. The recombinant protein encoded by DLK06_RS13370 was expressed in Escherichia coli (E. coli) and demonstrated the capacity to catalyze the conversion of DON into 3-Acetyl-deoxynivalenol (3-ADON), as confirmed by HPLC analysis. In conclusion, our findings confirm that the acyltransferase encoded by DLK06-RS13370 is responsible for the acetylation of DON. This sheds light on the co-occurrence of DON and its acetyl-derivatives in wheat-based products. DATA AVAILABILITY: Not applicable.

Genome-wide identification of actin-depolymerizing factor gene family and their expression patterns under various abiotic stresses in soybean (Glycine max).

The actin-depolymerizing factor (ADF) encoded by a family of genes is highly conserved among eukaryotes and plays critical roles in the various processes of plant growth, development, and stress responses via the remodeling of the architecture of the actin cytoskeleton. However, the ADF family and the encoded proteins in soybean (Glycine max) have not yet been systematically investigated. In this study, 18 GmADF genes (GmADF1 - GmADF18) were identified in the soybean genome and were mapped to 14 different chromosomes. Phylogenetic analysis classified them into four groups, which was confirmed by their structure and the distribution of conserved motifs in the encoded proteins. Additionally, 29 paralogous gene pairs were identified in the GmADF family, and analysis of their Ka/Ks ratios indicated their purity-based selection during the evolutionary expansion of the soybean genome. The analysis of the expression profiles based on the RNA-seq and qRT-PCR data indicated that GmADFs were diversely expressed in different organs and tissues, with most of them responding actively to drought- and salt-induced stresses, suggesting the critical roles played by them in various biological processes. Overall, our study shows that GmADF genes may play a crucial role in response to various abiotic stresses in soybean, and the highly inducible candidate genes could be used for further functional studies and molecular breeding in soybean.

Effect of induced molting on ovarian function remodeling in laying hens.

Induced molting (IM) can restore the laying rate of aged laying hens to the peak level of laying and rejuvenate ovarian function for the second laying cycle. To explore the mechanism of ovarian function remodeling during IM in laying hens, in this study, ninety 71-wk-old laying lady hens with 60% laying rate and uniform weight were selected for molting induction by fasting. Samples (serum and fresh ovarian tissue) were collected on the day before fasting (F0), the 3rd and 16th days of fasting (F3, F16), and the 6th, 15th, 32nd days of refeeding (R6, R15, and R32), and the number of follicles in each period was counted. Then, the reproductive hormone levels in serum and antioxidant levels in ovarian tissues were detected at different stages, and the gene expression of the KIT-PI3K-PTEN-AKT pathway and GDF-9 in ovaries was measured by qRT-PCR. The results showed that the laying rate increased rapidly after refeeding and returned to the prefasting level by R32. At F16 and R6, the number of mature follicles significantly decreased; the number of primary and secondary follicles significantly increased; the contents of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P4) in serum decreased; the relative expression of KIT, PI3K, AKT, and GDF-9 significantly increased; and that of PTEN significantly decreased. At R15 and R32, except for GDF-9, which maintained a high expression state, other indicators showed opposing trends to those observed at F16 and R6. In conclusion, IM activated the KIT-PI3K-PTEN-AKT signaling pathway and promoted the activation of primordial follicles during the fasting period and early resumption of feeding; gonadotropin secretion increased gradually, which promoted the rapid development of primary and secondary follicles to mature follicles and ovulation. This study explained the mechanism of ovarian function remodeling in the process of IM and provided a theoretical basis for improving the ovarian function of laying hens and optimizing the IM program.

gga-miR-449b-5p Regulates Steroid Hormone Synthesis in Laying Hen Ovarian Granulosa Cells by Targeting the IGF2BP3 Gene.

MiRNAs have been found to be involved in the regulation of ovarian function as important post-transcriptional regulators, including regulators of follicular development, steroidogenesis, cell atresia, and even the development of ovarian cancer. In this study, we evaluated the regulatory role of gga-miR-449b-5p in follicular growth and steroid synthesis in ovarian granulosa cells (GCs) of laying hens through qRT-PCR, ELISAs, western blotting and dual-luciferase reporter assays, which have been described in our previous study. We demonstrated that gga-miR-449b-5p was widely expressed in granulosa and theca layers of the different-sized follicles, especially in the granulosa layer. The gga-miR-449b-5p had no significant effect on the proliferation of GCs, but could significantly regulate the expression of key steroidogenesis-related genes (StAR and CYP19A1) (p < 0.01) and the secretion of P4 and E2 (p < 0.01 and p < 0.05). Further research showed that gga-miR-449b-5p could target IGF2BP3 and downregulate the mRNA and protein expression of IGF2BP3 (p < 0.05). Therefore, this study suggests that gga-miR-449b-5p is a potent regulator of the synthesis of steroid hormones in GCs by targeting the expression of IGF2BP3 and may contribute to a better understanding of the role of functional miRNAs in laying hen ovarian development.

A functional analysis of the effects of the molecular weight of dextran on ε-polylysine-dextran conjugate created through the maillard reaction.

The present study mainly examines the effects of molecular weight of dextran on the reaction rate and functional characteristics between ε-polylysine (PL) and dextran. The reaction kinetics, grafting degree and gel permeation chromatography are employed to evaluate the reaction rate and extent of these lard reaction. We find low activation energy (Ea) values that indicate that dextran with high molecular weight (HMD) exhibits a higher reaction rate with PL than that that of dextran with middle molecular weight (MMD) and low molecular weight (LMD). As for the functional characteristics of the formed conjugate, the conjugate of PL-HMD possesses a higher emulsifying activity, and PL-LMD exhibits higher antimicrobial activity than other molecular weight of dextran. We observe that long heating time at high temperatures can induce the partial degradation of the formed conjugates, which is reflected in the decreasing of the emulsifying and antimicrobial activity of PL-dextran conjugates.

Tumor-induced erythroid precursor-differentiated myeloid cells mediate immunosuppression and curtail anti-PD-1/PD-L1 treatment efficacy.

Despite the unprecedented success of immune checkpoint inhibitors (ICIs) as anti-cancer therapy, it remains a prevailing clinical need to identify additional mechanisms underlying ICI therapeutic efficacy and potential drug resistance. Here, using lineage tracking in cancer patients and tumor-bearing mice, we demonstrate that erythroid progenitor cells lose their developmental potential and switch to the myeloid lineage. Single-cell transcriptome analyses reveal that, notwithstanding quantitative differences in erythroid gene expression, erythroid differentiated myeloid cells (EDMCs) are transcriptionally indistinguishable from their myeloid-originated counterparts. EDMCs possess multifaceted machinery to curtail T cell-mediated anti-tumor responses. Consequently, EDMC content within tumor tissues is negatively associated with T cell inflammation for the majority of solid cancers; moreover, EDMC enrichment, in accordance with anemia manifestation, is predictive of poor prognosis in various cohorts of patients undergoing ICI therapy. Together, our findings reveal a feedforward mechanism by which tumors exploit anemia-triggered erythropoiesis for myeloid transdifferentiation and immunosuppression.

3D reconstruction of dynamic behaviors of vacuum arcs under transverse magnetic fields via computer tomography.

The transverse magnetic field (TMF) contacts make the vacuum arcs deviate from the axisymmetric structure, so complete spatiotemporal evolution information of the plasma cannot be obtained by adopting one- or two-dimensional (2D) diagnostic methods. To address the issues, computer tomography was introduced in this paper. First, a multi-angle diagnostic imaging system based on split fiber bundles was proposed, which used a high-speed camera to simultaneously acquire eight angles of the arc image over time. In addition, a tomography algorithm called the maximum likelihood expectation maximum with Split Bregman denoising was proposed to reconstruct the dynamic spatiotemporal characteristics of the arc under complex conditions. Then, the three-dimensional (3D) distribution of Cu i and Cr i particles inside the contact gap was obtained by adopting optical filters. The 3D distribution of the vacuum arc had shown an obvious asymmetrical pattern under the TMF contacts, and there was a ring-like aggregation zone inside the arc, which can cause severe ablation on the anode contacts. According to the reconstructed 3D distribution of Cu i and Cr i, it is found that the metal vapor was mainly concentrated near the electrode surface and showed a clear distribution of non-uniform aggregates, while the concentration of particles in the gap was low. Moreover, on the cathode surface, the cathode spots moved in the form of groups driven by the TMF, while the anode surface was ablated by the electric arc, and the metal vapor existed in the form of bands.

A Serum Metabolic Profiling Analysis During the Formation of Fatty Liver in Landes Geese via GC-TOF/MS.

During the process of fatty liver production by overfeeding, the levels of endogenous metabolites in the serum of geese would change dramatically. This study investigated the effects of overfeeding on serum metabolism of Landes geese and the underlying mechanisms using a metabolomics approach. Sixty Landes geese of the same age were randomly divided into the following three groups with 20 replicates in each group: D0 group (free from gavage); D7 group (overfeeding for 7 days); D25 group (overfeeding for 25 days). At the end of the experiment, 10 geese of similar weight from each group were selected for slaughter and sampling. The results showed that overfeeding significantly increased the body weight and the liver weight of geese. Serum enzymatic activities and serum lipid levels were significantly enhanced following overfeeding. Gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS) was employed to explore the serum metabolic patterns, and to identify potential contributors to the formation of fatty liver and the correlated metabolic pathways. Relative to overfeeding for 7 days, a large number of endogenous molecules in serum of geese overfed for 25 days were altered. Continuous elevated levels of pyruvic acid, alanine, proline and beta-glycerophosphoric acid and reduced lactic acid level were observed in the serum of overfed geese. Pathway exploration found that the most of significantly different metabolites were involved in amino acids, carbohydrate and lipid metabolism. The present study exhibited the efficient capability of Landes geese to produce fatty liver, identified potential biomarkers and disturbed metabolic pathways in liver steatosis. These findings might reveal the underlying mechanisms of fatty liver formation and provide some theoretical basis for the diagnosis and treatment of liver diseases.

Alterations in cecal microbiota and intestinal barrier function of laying hens fed on fluoride supplemented diets.

The objective of this study was to investigate the effects of fluorine at levels of 31, 431, 1237 mg/kg feed on cecum microbe, short-chain fatty acids (SCFAs) and intestinal barrier function of laying hens. The results showed that the intestinal morphology and ultrastructure were damaged by dietary high F intake. The mRNA expression levels of zonula occludens-1, zonula occludens-2, claudin-1, and claudin-4 were decreased in jejunum and ileum. However, the concentrations of serum diamine oxidase, and D-lactic acid and intestinal contents of interleukin 1 beta, interleukin 6, and Tumor necrosis factor-alpha were increased. Consistent with this, dietary high F intake altered the cecum microbiota, with increasing the concentration of pathogens, such as Proteobacteria and Escherichia-Shigella, as well as, decreasing the contents of beneficial bacteria, such as Lactobacillus, and expectedly, reduced the SCFAs concentrations. In conclusion, the actual results confirmed that (1) high dietary F intake could damage the intestinal structure and function, with impaired intestinal barrier and intestinal inflammation, and (2) destroy the cecum microbial homeostasis, and decrease the concentrations of SCFAs, which aggravate the incidence of intestinal inflammation in laying hens.

Early inoculation with caecal fermentation broth alters small intestine morphology, gene expression of tight junction proteins in the ileum, and the caecal metabolomic profiling of broilers.

BACKGROUND: The establishment of stable microbiota in early life is beneficial to the individual. Changes in the intestinal environment during early life play a crucial role in modulating the gut microbiota. Therefore, early intervention to change the intestinal environment can be regarded as a new regulation strategy for the growth and health of poultry. However, the effects of intestinal environmental changes on host physiology and metabolism are rarely reported. This study was conducted to investigate the effects of early inoculation with caecal fermentation broth on small intestine morphology, gene expression of tight junction proteins in the ileum, and cecum microbial metabolism of broilers. RESULTS: Our data showed that early inoculation with caecal fermentation broth could improve intestine morphology. The small intestine villus height was significantly increased (P < 0.05) in the intervened broilers compared to the control group, especially on day 28. A similar result was observed in the ratio of villus height to crypt depth (P < 0.05). Meanwhile, we found early inoculation significantly increased (P < 0.05) the expression levels of zonula occludens-1 (ZO1) on days 14 and 28, claudin-1 (CLDN1) on day 28, whereas the gene expression of claudin-2 (CLDN2) was significantly decreased (P < 0.05) on days 14 and 28. Gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS) technology was further implemented to systematically evaluate the microbial metabolite profiles. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) displayed a distinct trend towards separation between the fermentation broth group (F group) and the control group (C group). The differentially expressed metabolites were identified, and they were mainly functionally enriched in beta-alanine metabolism and biosynthesis of unsaturated fatty acids. In addition, 1,3-diaminopropane was selected as a key biomarker that responded to early inoculation with caecal fermentation broth. CONCLUSIONS: These results provide insight into intestinal metabolomics and confirm that early inoculation with caecal fermentation broth can be used as a potential strategy to improve intestinal health of broilers.

Developmental and Tissue Patterns of the Basal Expression of Chicken Avian ß-Defensins.

Defensins are a class of antimicrobial peptides in vertebrates that function as the first line of innate immunity with potent antimicrobial and immunomodulatory activities. Fourteen defensins, namely, avian ß-defensin 1 to 14 (AvBD1-14), have been identified in chickens. Before characterizing the role of AvBDs in innate immunity during the early development of chickens, we collected tissue segments from the liver, spleen, and gastrointestinal (GI) tract including the esophagus, crop, proventriculus, gizzard, duodenum, jejunum, ileum, cecum, and colon from broilers at days 1, 3, 7, 14, and 28. After RNA isolation and reverse transcription, we determined the expression levels of the 14 AvBD genes in these tissues during the first 28 days after hatching by real-time PCR. The results suggested the AvBDs were widely expressed in the chicken liver, spleen, and gastrointestinal (GI) tract. Interestingly, we did not detect AvBD11 expressed in the GI tract, even in the liver and spleen. Additionally, AvBDs were differentially expressed in the chicken GI tract. AvBD5 and AvBD14 were expressed most abundantly in the proximal GI tract, especially the esophagus and crop. Moreover, AvBD5, AvBD7, AvBD9, and AvBD14 were expressed in an inverted-V pattern with the peak being the observed expression at days 3, 7, or 14 in the chicken spleen, esophagus, duodenum, and cecum. Other AvBDs presented biphasic or inverted-V expression patterns in different tissues. The expression levels of all detected AvBDs were strengthened after hatching rather than decreasing steadily. Therefore, AvBDs were found to be expressed widely in the chicken liver, spleen, and GI tract and their expression levels were primarily up regulated during the early development of chicken, implying the potential essential roles of AvBDs in early innate defense and infection resistance of chickens.