The bone morphogenetic protein (BMP) gene family comprises a group of multifunctional cytokines that play important roles in limb development, bone formation, fat deposition, and reproductive traits of vertebrates. However, no systematic and comprehensive investigations of the various traits of the whole family members have been conducted, particularly in chickens. Here, we performed genome-wide screening and identified 14 BMP genes, which were classified into the BMP2/4, BMP5/6/7/8A, growth differentiation factor (GDF) 2/BMP10, GDF5/6/7, and GDF11/BMP3/15 subfamilies. Genetic variation pattern analysis showed that BMP genes were responsible for the artificial selection of commercial broilers and layers, with BMP2, BMP6, and GDF7 likely contributing significantly to the formation of both specialized meat- and egg-type lines, whereas BMP7 likely contributed more to the formation of meat-type lines. Genetic association analysis showed that single nucleotide polymorphisms (SNPs) in the BMP7 intron region were associated with body weight, breast muscle weight, leg weight, abdominal fat weights and contents of total cholesterol (T-CHO), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) in serum. Additionally, gain- and loss-of-function assays demonstrated that BMP7 promoted the proliferation, myogenic differentiation, and lipid droplet accumulation in myoblasts; enhanced lipid synthesis in hepatocytes; promoted the proliferation and inhibited adipogenic differentiation of intramuscular preadipocytes; and induced the proliferation and adipogenic differentiation of abdominal preadipocytes. These results provide novel insights into the role of BMP genes in chicken growth, reproductive regulation, and lipid deposition and could be used to develop genetic markers for breeding selection in chickens.

Accumulating evidence has indicated that microRNAs (miRNAs) participate in chicken skeletal muscle development by post-transcriptionally regulating myogenesis-related gene expression. Our previous study showed that miR-34c-5p inhibited proliferation and myogenic differentiation of chicken primary myoblasts (CPMs), but its molecular mechanisms remain unclear. Here, miR-34c-5p was overexpressed in CPMs for transcriptome sequencing. The 159 differentially expressed genes (DEGs) were identified and were mainly involved in myogenesis-related processes and signaling pathways, including cytoskeleton regulation, PPAR, and cardiac muscle contraction. Intersection of DEGs and predicted targets of miR-34c-5p yielded 15 candidate genes. Of these, miR-34c-5p could inhibit the mRNA expression of MYH7B and TGM4 genes by directly interact with their 3 ' untranslated regions as determined by dual-luciferase reporter systems Gain- and loss-of-function assays demonstrated that TGM4 gene could promote CPMs proliferation. These findings elucidate the regulatory network of miR-34c-5p underlying myogenesis and provide potential molecular marker for genetic improvement of meat production in chicken.

MicroRNAs (miRNAs) have been increasingly involved in mammalian lipid metabolism. However, their regulatory roles and molecular mechanisms in abdominal fat deposition in chicken remain largely unexplored. In this study, based on the previous miRNA transcriptome data during chicken abdominal preadipocytes' adipogenic differentiation, we explored the biological functions and regulatory mechanisms of a differentially expressed miRNA, gga-let-7c-3p, in adipogenesis. Gain- and loss-of-function assays elucidated that gga-let-7c-3p significantly decreased viability, proliferation, cell cycle progression, intracellular lipid droplet accumulation and triglyceride content, as well as the mRNA expression of proliferation- and lipid metabolism-related genes in chicken abdominal preadipocytes. Dual-luciferase reporter assay confirmed that gga-let-7c-3p could directly interact with the 3'UTR of the transcription factor-peroxisome proliferator activated the receptor delta (PPARD) gene and thus inhibited its post-transcriptional expression. The PPARD gene significantly decreased viability, proliferation, and cell cycle progression, while it increased intracellular lipid droplet accumulation and triglyceride content of chicken abdominal preadipocytes, paralleling with the mRNA expression of proliferation- and lipid metabolism-related genes. Collectively, gga-let-7c-3p could inhibit the proliferation and adipogenic differentiation of chicken abdominal preadipocytes, at least by targeting the PPARD gene. These findings reveal the regulatory mechanisms of the gga-let-7c-3p/PPARD axis in chicken abdominal adipogenesis, and could provide potential molecular markers for lean line broiler breeding.

Black-boned chicken is a native and valuable breed that is very important in the meat products of China. However, the molecular mechanisms underlying differences in muscle flavor between sexes remain unclear. In this study, 360-day-old male (BM, n = 6) and female (BF, n = 6) Xichuan black-boned chickens were used to screen differential lipids and differential flavor compounds in breast muscle tissue by lipidomics and flavoromics. This was followed by multivariate statistical analysis, functional enrichment and correlation network analysis of the differential lipids and flavor compounds obtained. Lipidomics identified 419 differential lipids associated with BM vs. BF, which were mainly enriched in glycerolipid metabolism and metabolic pathways. Flavoromics analysis identified 61 differential flavor compounds, and enrichment analysis showed that the terpenoid backbone biosynthesis pathway may be correlated with chicken muscle flavor formation. Correlation analysis revealed that triglyceride-type lipid molecules were closely related to the flavor compound 3-ethyl-2-methylheptane. These findings provide novel insights into the sex-related differences in the meat quality of Xichuan black-boned chickens, offering important data for their recognition and evaluation.

Abstract Fasting‐induced molting (FIM) rejuvenates the laying cycle in hens; however, the fasting process may result in intestinal dysbiosis, which compromises host immunity and disrupts the intestine‐liver function. Consequently, investigating the changes in gut microbiota during FIM and its impacts on gut‐liver metabolic homeostasis is crucial for enhancing the efficiency of FIM in laying hens. Here, a total of 90 laying hens, aged 60 weeks, were selected for the FIM. Samples were collected at four time points: the day before fasting, the 15th day of fasting, the 5th day of refeeding, and the 47th day of refeeding. Metagenomic sequencing and non‐targeted metabolomics were employed to investigate the roles of the gut microbiota and metabolites in the remodeling of gut–liver function, focusing on intestinal injury‐repair mechanisms and changes in liver function. During the fasting period, the abundance of harmful microbiota and metabolites increase, leading to intestinal injury. This process activates the TGF‐beta signaling pathway, promoting intestinal stem cell proliferation. Simultaneously, liver function dysfunction as evidenced by elevated bile acid levels in the liver and serum and activation of the non‐classical bile acid synthesis pathway. During the refeeding period, the previously observed effects were reversed, leading to the remodeling of the intestinal microbiota and gut‐liver function. We identified key microorganisms (Liquorilactobacillus mali and Tissierellia bacterium KA00581) and functional metabolites (d‐Panthenol and 3‐hydroxyanthranilic acid (3‐HAA)) involved in intestinal‐liver function during FIM. Notably, d‐Panthenol promotes chicken small intestinal organoid branching and growth, enhances barrier function, and reduces inflammation. Our study underscores the role of gut microbiota in gut‐liver injury during FIM in laying hens, suggesting potential probiotic‐ or metabolite‐based interventions to mitigate gut‐liver injury and facilitate recovery.

Adiponectin, an adipocyte-derived adipokine, plays a key regulatory role in physiological processes such as energy balance, glucose metabolism, and fatty acid oxidation. Evidence from animal studies indicates that adiponectin is involved in the regulation of reproductive performance by mediating molecular crosstalk between energy metabolism and the reproductive system. As the core regulatory center for animal reproduction, the hypothalamic-pituitary-gonadal (HPG) axis exhibits a close link between its functional state and the body's energy homeostasis. This review systematically summarizes the expression patterns and molecular mechanisms of adiponectin and its receptors at different levels of the animal HPG axis. It provides a theoretical basis for future research and applications of adiponectin in animal reproduction.

This study investigated the effects of dietary supplementation with Vitamin E (VE) and selenium (Se) on immunostressed broilers. In the experiment, a total of 576 Gushi chickens were randomly allocated into 12 groups. They were respectively fed diets with different levels of VE and Se. Lipopolysaccharide (LPS) immune treatment was administered at 23, 25, and 27 days of age. At 28 days of age, the antioxidant indicators and immune factors in their serum, liver, and intestine were measured. The results indicated that (1) LPS treatment significantly elevated the contents of nitric oxide (NO) and nitric oxide synthase (NOS) in the duodenum and jejunum (p < 0.01). Conversely, adding VE and Se to the diet of LPS-treated chicks could significantly decrease the content of NO in the duodenum and the activities of NOS in the duodenum and jejunum (p < 0.01). (2) LPS treatment significantly decreased the content of malondialdehyde (MDA) in the liver of broilers, glutathione peroxidase (GSH-Px), and the activities of serum superoxide dismutase (SOD) (p < 0.01). Dietary supplementation of selenium could significantly reduce the content of MDA (p < 0.01), and the treatment groups with 200 mg/kg VE and 0.6 mg/kg Se exhibited the most favorable effects. (3) Adding Se or VE to the diet of LPS-treated chicks could significantly increase the thymus index and spleen index (p < 0.05) and significantly decrease the bursa of Fabricius index (p < 0.05). Among them, the thymus index was the highest in the 100 mg/kg VE group, and the interaction of the three factors had a significant influence on the thymus index and bursa of Fabricius index (p < 0.05). (4) The level ofinterleukin-6 (IL-6) in the serum of broilers in the LPS treatment group was significantly increased. However, selenium and Vitamin E were added to the diet of LPS-treated chicks to reduce the contents of serum IL-6 and IL-8, as well as adrenocorticotropic hormone (ACTH) and tumor necrosis factor-α (TNF-α). Moreover, the interaction of the three factors has a significant impact on immune indicators (p < 0.01). In conclusion, adding 100–200 mg/kg of VE and 0.6 mg/kg of Se to the diet of broiler chickens has certain advantages in enhancing immunity and antioxidant capacity.

As a crucial component of agriculture, livestock and poultry production supplies high-quality animal protein and is essential for the stability of food safety, ecological environment, human health, and global sustainability. However, frequent epidemics have emerged as a major constraint on industry development, with traditional vaccine and drug-based controls facing challenges such as rapid pathogen mutation, environmental pollution, and drug residue risks. Disease-resistant breeding thus offers a crucial strategy for sustainable livestock farming, yet its progress is hindered by the lack of effective molecular targets for major epizootics. Extensive studies on adaptive immune regulation have identified numerous regulatory genes and molecular targets associated with disease resistance, offering significant potential for breeding applications. Nevertheless, despite the well-established role of adaptive immunity in human medicine, its utilization in livestock breeding remains largely underdeveloped. This review outlines the significance and current status of disease-resistant breeding, focuses on adaptive immune mechanisms, and proposes innovative strategies.

Body weight (BW) serves as a core indicator for evaluating chicken growth performance and implementing early individual selective breeding. Our previous studies have verified that 8-week body weight (BW8) exhibits a significantly positive correlation with body weights at 10 and 12 weeks of age in chickens, implying that early body weight can be used to predict late growth phenotypes; nevertheless, the underlying genetic regulatory mechanisms remain elusive. Multiple investigations on growth traits of livestock have confirmed that the NCAPG-LCORL locus acted as a critical candidate interval associated with growth-related traits. In the present study, an F2 segregating population derived from the cross of Gushi chickens and Anka broilers was used as experimental material. Single-nucleotide polymorphism (SNP) screening within the NCAPG-LCORL locus was performed based on GBS data, followed by the LD analysis. A total of eight SNPs were identified to be significantly associated with economic growth traits in chickens, including four tag SNPs and four non-tag SNPs. In vitro functional validation using chicken skeletal muscle satellite cells (SMSCs) revealed functional divergence between NCAPG and LCORL during myocyte development: NCAPG facilitated SMSCs proliferation while repressing SMSCs differentiation, whereas LCORL exerted positive regulatory effects on both proliferation and differentiation of SMSCs. Collectively, NCAPG modulates whole-body chicken growth by remodeling the dynamic balance between proliferation and differentiation of skeletal muscle satellite cells. In contrast, LCORL simultaneously promotes myocyte proliferation and differentiation to accelerate skeletal muscle development, thereby enhancing chicken growth performance. This study elucidates the regulatory roles of the NCAPG-LCORL locus in chicken growth at both the molecular marker and cellular functional levels, laying a theoretical foundation for marker-assisted selection of growth traits in chicken breeding.

Semen cryopreservation represents a pivotal technology for the long-term conservation and efficient utilization of poultry genetic resources. The primary challenge impeding the implementation of this technology pertains to the phenomenon of frozen-thaw-induced oxidative stress damage to spermatozoa. Zinc oxide nanoparticles (ZnO NPs) have been demonstrated to exhibit remarkable antioxidant capacity within the context of biomedical applications. The present study therefore systematically evaluated the effects of adding ZnO NPs to a dimethylformamide (DMF) cryoprotectant on the morphology, antioxidant capacity, and reproductive potential of frozen-thawed sperm. The results demonstrated that, in comparison with the DMF group, the ZnO-DMF group exhibited significantly increased plasma membrane integrity, mitochondrial activity (MA), total antioxidant capacity (TAC), and glutathione peroxidase (GPX) and glutathione reductase (GR) activity in frozen-thawed sperm (P < 0.05). Concurrently, the rates of abnormal morphology, DNA fragmentation index (DFI), and malondialdehyde (MDA) content were significantly reduced (P < 0.05). Following artificial insemination, the fertilization rate of the experimental group 87.92% ± 10.66, the hatching rate was 97.79% ± 3.59, and late embryonic mortality was found to be significantly lower than in the control group (P < 0.05). In summary, the study demonstrates that ZnO NPs enhance sperm antioxidant capacity and exhibit synergistic protective effects with DMF, effectively mitigating cryopreservation-induced damage. This finding provides scientific rationale and technical support for the optimisation of rooster semen cryopreservation protocols and the enhancement of the efficiency of poultry genetic resource conservation.

Spermatogenesis relies on the intricate interactions between testicular somatic cells and germ cells. While follicle-stimulating hormone (FSH) and testosterone (T) are considered pivotal regulatory factors in this process, the mechanisms by which these hormones regulate the spermatogonial stem cell (SSC) microenvironment via Sertoli cells during testicular development in roosters remain unclear. Here, we examined how FSH and T regulate Sertoli-cell proliferation and the expression of glial cell-derived neurotrophic factor (GDNF) during rooster testicular development. We observed that at 4 weeks of age, the seminiferous tubules of roosters were fully developed, accompanied by the migration of spermatocytes into the lumen. At this stage, both serum and testicular levels of FSH and T were elevated in parallel. In highly purified Sertoli cells cultures, FSH treatment (25-100 ng/mL) significantly promoted proliferation and cell-cycle progression, and induced GDNF protein expression in a time- and dose-dependent manner, with the strongest response observed at 75 ng/mL. Although T did not significantly affect Sertoli cell proliferation, it markedly upregulated GDNF protein expression via the androgen receptor (AR) signaling pathway. Specifically, T (0.1-0.4 ng/mL) increased GDNF without altering proliferation, and this effect was blunted by pharmacological AR blockade (enzalutamide), indicating AR dependence. Furthermore, combined treatment with FSH and T demonstrated a synergistic effect, amplifying the expression of GDNF protein. In vivo experiments revealed that subcutaneous FSH administration increased Sertoli-cell proliferative activity (PCNA) and testicular growth, whereas testosterone administration enhanced testicular GDNF expression. Notably, combined FSH+T treatment produced the highest testicular GDNF level among groups, consistent with a synergistic effect in vivo. These findings suggest that FSH drives the expansion of Sertoli cell numbers by promoting their proliferation and cell cycle progression, while testosterone enhances the functional maturation of Sertoli cells through the regulation of GDNF expression. The synergistic actions of these two hormones together optimize the spermatogenic microenvironment, providing novel insights into the hormonal regulation of male reproduction.

The gut microbiome possesses substantial genetic diversity that supports microbial adaptation, but the genomic variation patterns across its prokaryotic and viral populations remain incompletely characterized. Through integrated metagenomic and metatranscriptomic analysis of ten indigenous chicken breeds from China, we recovered 1527 representative prokaryotic MAGs, 37,555 representative DNA viral contigs, and 1867 representative RNA viral contigs (primarily comprising Bacillota/Bacteroidota, Uroviricota, and Lenarviricota/Pisuviricota, respectively). By integrating complementary short-read and long-read metagenomics with metatranscriptomics, we identified structural variants (SVs) and single-nucleotide variants (SNVs) in these cross-kingdom genomes. Positive SV-SNV density correlations occurred consistently across all microbial groups, indicating coordinated mutational processes. DNA viruses exhibited the highest variant prevalence (86.9

Circular RNAs (circRNAs) exert crucial functions in mammalian reproduction; however, their regulation underlying chicken reproduction remains unclear. Here, time-course transcriptome profiles of circRNAs were constructed in chicken ovarian tissues across the entire egg-laying cycle (15 W, 20 W, 30 W, 70 W, 90 W). A total of 6551 circRNAs were identified, and most were derived from exon-exon backsplicing with 400-600 nt. Of these, 1556 circRNAs harbour translation potential in both IRES- and m6A modification-dependent manners. The 1894 differentially expressed circRNAs (DE-circRNAs) exhibited stage-specific expression patterns, and were clustered into 6 significantly co-expressed subclusters and enriched in multiple signaling pathways involving follicular development. Weighted gene co-expression network analysis detected 1016 hub circRNAs, of which 136 circRNAs were co-expressed DE-circRNAs and considered as key candidates regulating chicken ovarian development. These key circRNAs may post-transcriptionally regulate folliculogenesis-related gene via competitive endogenous RNA mechanism. This study reveals potential regulatory roles of circRNAs in chicken ovarian development and egg-laying performance.

The quality of hatching eggs and their hatchability are key factors affecting the production efficiency of breeding flocks. The quality of hatching eggs is commonly graded directly based on the eggshell quality. Our study monitored the eggshell quality and hatchability in Hy-Line Brown laying hens aged 23 to 73 weeks, to determine core eigenvectors that influence hatchability from multiple eggshell quality indicators. Hatching performance indicators, including fertile egg rate, hatchability of fertile eggs and hatchability of eggs set, were found to exhibit a trend of low level in early laying stage, and increased to a peak at 39 weeks of age during mid-laying stage, followed by a continuous decline in late laying stage. Similar trend also observed in eggshell quality indicators, such as eggshell strength, eggshell thickness, eggshell weight, eggshell rate and eggshell microstructure. Canonical correlation analysis revealed egg weight, equatorial eggshell thickness and pointed end eggshell thickness showed strong correlation with the main indicators affecting hatchability of fertile eggs (r = 0.987, P = 0.013). Further, shell gland RNA sequencing was applied to explore candidate genes or pathways that might affect eggshell thickness. Short time series expression miner (STEM) analysis identified several key genes (ATP2C2, CA9, CDC20B, WNT4, WNT7A and CACNB3) that were enriched in pathways related to calcium signaling, bicarbonate metabolism, vesicle transport and Wnt signaling, thereby highlighting their potential critical roles in eggshell thickness regulation. Our findings preliminarily delineate the relationship between easily measurable eggshell quality and hatchability, which provides a theoretical basis and candidate gene targets for improving hatching performance.

N6-methyladenosine (m6A) is the most common and abundant internal chemical modification in eukaryotic mRNA and long non-coding RNA (lncRNA). This dynamic and reversible epitranscriptional modification is mediated by a collaborative action of methyltransferases (writers), demethylases (erasers), and recognition proteins (readers) and represents an important epigenetic regulatory mechanism at the post-transcriptional level. LncRNAs are a class of RNA molecules that are longer than 200 nucleotides and lack the potential to encode proteins. They can participate in the fine regulation of gene expression at the transcriptional, post-transcriptional and epigenetic levels through various mechanisms such as cis-regulation and trans-regulation. In recent years, the interactive regulation of m6A modification and lncRNA has become a research hotspot. The precise regulatory network jointly constructed by these two elements plays a core role in the formation and plasticity regulation of complex traits in animals. This article systematically elaborates on the regulatory roles and research progress of m6A modification-related lncRNAs in important economic traits such as muscle development, fat deposition, and immune response in poultry. In response to the current issues of insufficient functional validation and insufficient mechanism elucidation, it proposes that future research should integrate multi-omics combined analysis, temporal and spatial dynamic analysis, cross-species comparative studies, and gene editing methods to systematically clarify their intrinsic regulatory mechanisms. This will open up a new path for molecular design breeding of poultry for disease resistance, high yield, high quality, and high efficiency, and is of great significance for promoting genetic improvement of poultry and the sustainable development of the industry.

The intestinal microorganisms make an important contribution to the development of the host immune system and resistance to pathogen infections, especially early in life. Our previous study found that early inoculation with cecal fermentation broth could change the colonization patterns of intestinal microorganisms and enhance the immune performance in broilers. However, it remains unknown whether cecal fermentation broth inoculation can be used as a novel form of treatment against pathogenic infections. In this study, a pathological model of avian pathogenic Escherichia coli (E. coli) was established to investigate the mechanism of cecal fermentation broth against pathogen infection in broilers. A total of 180 newly hatched broilers were randomly divided into three groups: (1) negative control (Con) group, inoculated with sterile normal saline from 1 to 4 days of age; (2) positive control (NS + E.coli) group, inoculated with sterile normal saline from 1 to 3 days of age, infected with E.coli at 4 days of age; (3) fermentation broth prevention (FerB + E.coli) group, inoculated with fermentation broth from 1 to 3 days of age, infected with E.coli at 4 days of age. Subsequently, 8 individuals were randomly selected from each group for weighing followed by slaughter to determine relevant indicators at 7, 10, 14 and 21 days of age. The results showed that early inoculation with fermentation broth significantly alleviates the negative effects on growth performance and intestinal permeability caused by E. coli infection. Furthermore, enhanced small intestinal health was observed, as indicated by the increase in villus height and the ratio of villus height to crypt depth (V/C). The relative abundance of Bacteroidetes was higher in the prevention group, and the number of functional genes detected was significantly greater. Additionally, the concentration of propionic acid was substantially elevated in the prevention group, while butyric acid concentrations were significantly reduced in the challenge group. This study demonstrates that early intervention with cecal fermentation broth improves intestinal barrier function and immune performance in broilers by increasing the relative abundance of intestinal Bacteroides and promoting propionic acid synthesis. These findings provide a novel strategy for preventing intestinal inflammatory disorders in broilers, such as avian colibacillosis.

The effect of phosphatidylcholine and lysophosphatidylcholine on the maintenance of sperm motility in vitro was investigated. Sperm motility is a key determinant of reproductive efficiency in poultry production, influenced by seminal plasma factors. This study characterized phenotypic distinctions between high- and low-motility sperm from 40-week-old Yufen 1 roosters and elucidated underlying molecular mechanisms. Metabolomics analysis showed that seminal plasma was enriched in glycerophospholipid metabolic pathway, phosphatidylcholine and lysophosphatidylcholine were the main metabolites. The effect of phosphatidylcholine on the maintenance of sperm motility in vitro was tested and verified by sperm co-incubation experiments. Herein, the high-motility group showed significantly higher fertilization capacity when compared to the low-motility sperm (P < 0.05). Furthermore, the removal of seminal plasma impaired motility, while cross-exchange between high- and low-motility groups restored motility (P < 0.05) and marginally improved membrane integrity in low-motility sperm. Metabolomic profiling of seminal plasma revealed the effects of seminal plasma on sperm motility were associated with glycerophospholipid metabolism, lysine degradation, and arachidonic acid metabolism pathways. Among these pathways, The conversion from phosphatidylcholine to lysophosphatidylcholine, mediated by glycerophosphatidylcholine metabolism, becomes the key mechanistic driver. The content of phosphatidylcholine in seminal plasma significantly affects the motility, membrane integrity, and fertilization characteristics (P < 0.05), respectively. These findings underscore the importance of seminal plasma in sperm motility, as well as that phosphatidylcholine probably serves as a key regulator for sperm properties.

BACKGROUND:Long noncoding RNAs (lncRNAs) participate in various critical regulatory steps during myogenesis. LncRNAs can encode small peptides, which can regulate gene expression through multiple mechanisms, thereby participating in key biological processes. RESULTS:The lncRNAs were screened between proliferating and differentiating myoblast in chicken through RNA-seq and Ribo-seq. As a result, 178 DE-lncRNAs were identified in RNA-seq, and three of them were identified as differentially translated lncRNAs by Ribo-seq. Among them, lncMPD, which showed coding potential, was highly expressed in proliferating myoblast. It encoded a small peptide containing 74 amino acids, which was named MPD-74aa. MPD-74aa was validated via WB and mass spectrometry. We subsequently confirmed that MPD-74aa promotes myoblast proliferation and inhibits its differentiation. Co-IP revealed that MPD-74aa interacts with the protein CDK1. Moreover, MPD-74aa positively regulated the expression of CDK1. CONCLUSION:This study confirms that the lncMPD plays a crucial regulatory role in the chicken myogenesis by encoding the small peptide MPD-74aa. Mechanistically, MPD-74aa exerts its regulatory function through interaction with CDK1, a key protein marker of cell proliferation. These findings provide new insight into the molecular mechanisms about the coding capacity of lncRNA regulating chicken muscle development.

Declining egg production in hens is often accompanied by ovarian dysfunction. Emerging evidence suggests a link between intestinal abnormalities and reproductive endocrine disorders, yet whether gut dysbiosis contributes to this process via ferroptosis and mitochondria-associated pathways remains unclear. Here, we show that low-producing hens exhibit intestinal villus atrophy and downregulation of tight junction proteins in both ileum and ovary, accompanied by elevated inflammatory cytokines, impaired antioxidant defense, and aberrant expression of ferroptosis-related genes, indicating a coordinated disruption of intestinal–ovarian homeostasis in inflammation and iron metabolism. 16S rRNA sequencing revealed a markedly increased abundance of Lactobacillus species in high-producing hens, correlating positively with sex hormone levels and laying performance, whereas these bacteria were depleted in low-producing hens. Dietary supplementation with Lactobacillus paracasei R8 (L. paracasei R8) improved laying performance, alleviated intestinal and ovarian injury, and attenuated ferroptosis-associated alterations. In LPS-induced intestinal epithelial and ovarian cell models, L. paracasei R8 improved barrier function, increased mitochondrial membrane potential, reduced lipid peroxidation and intracellular Fe2⁺ accumulation, exerting effects comparable to the ferroptosis inhibitor Fer-1. Co-treatment with the mitochondrial inhibitor CsA partially abrogated these effects, implicating mitochondrial regulation in the mechanism of action. Taken together, these findings identify an intestinal–ovarian injury pattern in low-producing hens associated with gut microbiota imbalance and iron-dependent cell death, and suggest that L. paracasei R8 may serve as a potential probiotic intervention to improve laying performance by alleviating gut–ovary-related pathological alterations through modulation of mitochondrial function and ferroptosis-related pathways.

The liver of laying hens is the primary site for lipid synthesis and very-low-density lipoprotein (VLDL) assembly, essential for yolk formation. Unlike mammals, chickens do not require the canonical microsomal triglyceride transfer protein (MTTP) for the VLDL assembly. A newly identified gene, microsomal triglyceride transfer protein-like (MTTPL), is differently expressed during peak egg production and induced by estrogen. We demonstrated that MTTPL facilitates hepatic lipid export. Overexpression of MTTPL significantly reduced intracellular triglycerides (TG), total cholesterol (TC), and VLDL levels while increasing their extracellular concentrations, accompanied by upregulated expression of lipid-transport genes. In vivo, hepatic MTTPL knockdown impaired estrogen-induced lipid export. Mechanistically, PPARα directly activates the MTTPL promoter, and miR-7439-3p represses MTTPL via its 3'UTR; estrogen regulates MTTPL through PPARα-mediated transcriptional activation and post-transcriptional miR-7439-3p inhibition. This study identified MTTPL as a key hepatic lipid-transport mediator in laying hens, illuminating poultry-specific lipid metabolic regulation.