Non-Targeted Metabolomics Reveals the Metabolic Alterations in Response to Artificial Selective Breeding in the Fast-Growing Strains of Pacific Oyster

Pacific oyster(Crassostrea gigas)is one of the most important mollusks cultured all around the world.Selective breeding programs of Pacific oysters in China is initiated since 2006 and developed the genetically improved strain with fast-growing trait.However,little is known about the metabolic signatures of the fast-growing trait.In the present study,the non-targeted metabolomics was performed to analyze the metabolic signatures of adductor muscle tissue in one-year old Pacific oysters from fast-growing strain and the wild population.A total of 7767 and 10174 valid peaks were extracted and quantified in ESI^(+)and ESI^(−)modes,resulting in 399 and 381 annotated metabolites,respectively.PCA and OPLS-DA revealed that considerable separation among samples from fastgrowing strain and wild population,suggesting the differences in metabolic signatures.Meanwhile,81 significantly different metabolites(SDMs)were identified in the comparisons between fast-growing strain and wild population,based on the strict thresholds.It was found that there were highly correlation and conserved coordination among these SDMs.KEGG enrichment analysis indicated that the SDMs were tightly related to pantothenate and CoA biosynthesis,steroid hormone biosynthesis,riboflavin metabolism,and arginine and proline metabolism.Of them,the CoA biosynthesis and metabolism,affected by pantetheine and pantothenic acid,might be important for the growth of Pacific oysters under artificial selective breeding.The study provides the comprehensive views of metabolic signatures in response to artificially selective breeding,and is helpful to better understand the molecular mechanism of fastgrowing traits in Pacific oysters.

Effect of dietary arginine to lysine ratios on productive performance,meat quality,plasma and muscle metabolomics profile in fast-growing broiler chickens

Background: Due to the important functions of arginine in poultry,it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine.The present study aimed,therefore,to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance,breast meat quality attributes,incidence and severity of breast muscle myopathies and foot pad dermatitis(FPD),and plasma and muscle metabolomics profile in fast-growing broilers.Results: A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet(CON,digestible Arg:Lys ratio of 1.05,1.05,1.06 and 1.07 in each feeding phase,respectively) or the same basal diet supplemented on-top with crystalline L-arginine(ARG,digestible Arg:Lys ratio of 1.15,1.15,1.16 and 1.17,respectively).Productive parameters were determined at the end of each feeding phase(12,22,33,43 d).At slaughter(43 d),incidence and severity of FPD and breast myopathies were assessed,while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonancespectroscopy.The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d(1.352 vs.1.401,P < 0.05),22 d(1.398 vs.1.420; P < 0.01) and 33 d(1.494 vs.1.524; P < 0.05),and also tended to improve it in the overall period of trial(1.646 vs.1.675; P = 0.09).Body weight was significantly increased in ARG compared to CON group at 33 d(1,884 vs.1,829 g; P < 0.05).No significant effect was observed on meat quality attributes,breast myopathies and FPD occurrence.ARG birds showed significantly higher plasma concentration of arginine and leucine,and lower of acetoacetate,glutamate,adenosine and proline.Arginine and acetate concentrations were higher,whereas acetone and inosine levels were lower in the breast of ARG birds(P < 0.05).Conclusions: Taken together,these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Characteristics of fast-growing wood impregnated with nanoparticles

Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia.However,its wood is low quality with low density,and poor strength,durability,and dimensional stability.This study determined the effects of impregnation with monoethylene glycol(MEG)and nano-SiO2 on the characteristics of sengon wood,including its dimensional stability and density.Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain,anti-swelling efficiency,water uptake,bulking effect,and density.The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction.The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5%MEGSiO2.

Comparison of the morphometric dynamics of fast-growing and slow-growing strains of turbot Scophthalmus maximus

The dynamics of changes in body shape of fast-growing and slow-growing strains of turbot Scophthalmus maximus, and of the differences in body shape between the two strains, were evaluated from 3 to 27 months of age. The ratios of total length/body length, body width/body length and total length/body width were used as morphometric indices. The two strains exhibited different temporal trends in total length/body length but similar trends in body width/body length and total length/body width. Generally, body width/body length of the two strains increased with time and total length/body width decreased. Thus, the bodies of both fast-growing and slow-growing strains of turbot changed from a narrow to a more rounded shape. However, the ratio total length/body length was generally lower, body width/body length was mostly higher and total length/body width was consistently lower in the fast-growing strain than in the slowgrowing strain. Correlation analysis of the three shape ratios with body weight showed that total length/body length and total length/body width were unsuitable, and that width/body length was suitable, for use as a phenotypic marker for selective breeding of turbot for growth in weight.

Genome-wide investigation to assess copy number variants in the Italian local chicken population

Background Copy number variants(CNV)hold significant functional and evolutionary importance.Numerous ongoing CNV studies aim to elucidate the etiology of human diseases and gain insights into the population structure of livestock.High-density chips have enabled the detection of CNV with increased resolution,leading to the identification of even small CNV.This study aimed to identify CNV in local Italian chicken breeds and investigate their distribution across the genome.Results Copy number variants were mainly distributed across the first six chromosomes and primarily associated with loss type CNV.The majority of CNV in the investigated breeds were of types 0 and 1,and the minimum length of CNV was significantly larger than that reported in previous studies.Interestingly,a high proportion of the length of chromosome 16 was covered by copy number variation regions(CNVR),with the major histocompatibility complex being the likely cause.Among the genes identified within CNVR,only those present in at least five animals across breeds(n=95)were discussed to reduce the focus on redundant CNV.Some of these genes have been associated to functional traits in chickens.Notably,several CNVR on different chromosomes harbor genes related to muscle development,tissue-specific biological processes,heat stress resistance,and immune response.Quantitative trait loci(QTL)were also analyzed to investigate potential overlapping with the identified CNVR:54 out of the 95 gene-containing regions overlapped with 428 QTL associated to body weight and size,carcass characteristics,egg production,egg components,fat deposition,and feed intake.Conclusions The genomic phenomena reported in this study that can cause changes in the distribution of CNV within the genome over time and the comparison of these differences in CNVR of the local chicken breeds could help in preserving these genetic resources.

High expression circRALGPS2 in atretic follicle induces chicken granulosa cell apoptosis and autophagy via encoding a new protein

Background The reproductive performance of chickens mainly depends on the development of follicles.Abnor-mal follicle development can lead to decreased reproductive performance and even ovarian disease among chick-ens.Chicken is the only non-human animal with a high incidence of spontaneous ovarian cancer.In recent years,the involvement of circRNAs in follicle development and atresia regulation has been confirmed.Results In the present study,we used healthy and atretic chicken follicles for circRNA RNC-seq.The results showed differential expression of circRALGPS2.It was then confirmed that circRALGPS2 can translate into a protein,named cir-cRALGPS2-212aa,which has IRES activity.Next,we found that circRALGPS2-212aa promotes apoptosis and autophagy in chicken granulosa cells by forming a complex with PARP1 and HMGB1.Conclusions Our results revealed that circRALGPS2 can regulate chicken granulosa cell apoptosis and autophagy through the circRALGPS2-212aa/PARP1/HMGB1 axis.

Study on Microwave Pretreatment Technology to Improve the Effect of Shellac Impregnation of Fast-Growing Chinese Fir

To improve the mechanical properties of fast-growing Chinese fir(Cunnighamia lanceolate),expand its range of application,increase its value,and avoid the environmental pollution caused by impregnation with synthetic resin,Chinese fir was impregnated with a shellac solution.Since the shellac solution was difficult to penetrate into fast-growing Chinese fir,so microwave pretreatment was used to irradiate the wood to improve the permeability.This study investigated the effects of four factors,including the content of moisture in the wood before it was microwaved,the chamber pressure of microwave,the time of microwaving and the vacuum impregnation on the mechanical properties of Chinese fir wood.When the moisture content of wood before microwave was approximately 50%–60%,after microwaving and impregnation,the ultimate strength in static bending(modulus of rupture[MOR])and strength in compression perpendicular to the grain(SCPG)of the wood increased significantly.A microwave time of 100 seconds was more effective at improving the MOR and SCPG of the wood.If the wood was microwaved for too short or long period of time,the microwave pretreatment was not effective.When the samples were immersed in shellac for a longer period,the MOR and SCPG of Chinese fir gradually increased,but when the wood was impregnated for more than 12 hours,the increases were not significant.After the shellac penetrated the Chinese fir wood,it spread on the inner wall surface of tracheid to form a shellac film and easily formed plug-like deposits in microcapillaries.The use of Fourier-transform infrared spectroscopy,scanning electron microscopy and scanning electron microscopy-energy dispersion x-ray indicated that the microwave pretreatment can destroy the pit membranes on tracheids and facilitate the ability of shellac to penetrate the channel.

Determinants of foreign direct investment in fast-growing economies: evidence from the BRICS and MINT countries

The flow of foreign direct investment(FDI)into a country can benefit both the investing entity and host government.This study employed panel analysis to examine the factors that determine the direction of FDI to the fast-growing BRICS(Brazil,Russia,India,China,and South Africa)and MINT(Mexico,Indonesia,Nigeria,and Turkey)countries.First,we used a pooled time-series cross sectional analysis of data from 2001 to 2011 to estimate and model the determinants of FDI for three samples:BRICS only,MINT only,and BRICS and MINT combined.Then,a fixed effects approach was employed to provide the model for BRICS and MINT combined.The results demonstrate that market size,infrastructure availability,and trade openness play the most significant roles in attracting FDI to BRICS and MINT,while the roles of availability of natural resources and institutional quality are insignificant.To sustain and promote FDI inflow,the governments of BRICS and MINT must ensure that their countries remain attractive for investment by offering a level playing field for investors and political stability.BRICS and MINT governments also need to invest more in their human capital to ensure that their economies can absorb substantial skills and technology spillovers from FDI and promote sustainable long-term economic growth.This study is significant because it contributes to the literature on determinants of FDI by extending the scope of previous studies that often focused on BRICS only.

Investigation on taste characteristics and sensory perception of soft-boiled chicken during oral processing based on electronic tongue and electronic nose

The sensory perception of food is a dynamic process,which is closely related to the release of flavor substances during oral processing.It’s not only affected by the food material,but also subjected to the individual oral environment.To explore the oral processing characteristics of soft-boiled chicken,the sensory properties,texture,particle size,viscosity,characteristic values of electronic nose and tongue of different chicken samples were investigated.The correlation analysis showed that the physical characteristics especially the cohesiveness,springiness,resilience of the sample determined oral processing behavior.The addition of chicken skin played a role in lubrication during oral processing.The particle size of the bolus was heightened at the early stage,and the fluidity was enhanced in the end,which reduced the chewing time to the swallowing point and raised the aromatic compounds signal of electronic nose.But the effect of chicken skin on chicken thigh with relatively high fat content,was opposite in electronic nose,which had a certain masking effect on the perception of umami and sweet taste.In conclusion,fat played a critical role in chicken oral processing and chicken thigh had obvious advantages in comprehensive evaluation of soft-boiled chicken,which was more popular among people.

International Practice of Fast-Growing Innovative Companies

The purpose of the article is to compare the conditions of development and support of fast-growing companies in European countries, Asian countries, and Russia. The comparative analysis performed is of interest as certain countries, including Russia, face the problem of economic slowdown. However, the fast-growing companies are powerful catalysts for the growth of the gross domestic product and the employment of the population. The conclusion of the study is that there are common patterns in ongoing support programs for fast-growing companies： long term, state support, innovative company orientation, and concessional financing. At the same time, there are fundamental differences in approaches to the state support for innovative companies. The first approach relates to the natural development of the fast-growing innovation companies and their support programs （Germany, Denmark）; the second approach is aimed at artificially stimulating the growth of such companies （South Korea）. In Russia there are institutional features of supporting fast-growing companies： small businesses are the most vulnerable part of the economic system and they require state support in crisis situations. Therefore, the experience of European and Asian countries in terms of supporting innovative and fast-growing companies can have a positive impact on the development of innovative companies in Russia. And definitely it is important to try to understand the nature of Russian innovative fast-growing companies： do we see them as entrepreneurial business as we do in the Western companies？

Transcriptome-based analysis of key signaling pathways affecting the formation of primordial germ cell in chickens

Bone morphogenetic protein 4(BMP4)can induce the formation of chicken primordial germ cells(PGCs)in vitro;however,its regulatory mechanism in poultry remains unknown.This study aimed to use RNA-seq to analyze PGCs in chicken embryos and iPGCs induced by BMP4 in vitro,clarify the internal regulatory factors of PGCs,analyze the mechanism of the formation of PGCs,and lay a theoretical foundation for the further optimization of PGCs induction systems.Embryonic stem cells(ESCs),PGCs and iPGCs induced by BMP4 in vitro were collected.The transcriptional maps of the three cell types were studied using RNA-seq.The results showed 6,142 genes differentially expressed between PGCs and iPGCs,of which 2,728 were upregulated in iPGCs and 3,414 were downregulated in iPGCs.Compared to that in ESCs,BMP4 was significantly upregulated in PGCs and iPGCs.KEGG results showed that both the TGF-βand Wnt signaling pathways were activated during the formation of PGCs in vitro and in vivo,and the activation was more significant during iPGCs induced by BMP4.The expression of Nodal,an inhibitory factor of TGF-βsignaling,was significantly decreased in PGCs and iPGCs,but was not expressed in iPGCs,which further supports our conclusion.Additionally,the Lysosome and PI3K-AKT signaling pathways were significantly enriched in PGCs and iPGCs,respectively.Further,transmission electron microscopy(TEM)results showed that the number of autolysosomes was significantly higher after the addition of BMP4,which is consistent with the KEGG results.Furthermore,the number of PGCs was significantly reduced after ATG14 was interfered in vivo and in vitro.In conclusion,this study screened out the key signaling pathways during the formation of PGCs,aiming to provide help for enriching the mechanism network regulating PGCs formation in chicken and laying a theoretical foundation for further improving the efficiency of inducing PGCs in vitro.

Retinol is involved in the intestinal regeneration and strengthens the intestinal barrier during refeeding in broiler chickens

Fasting is typically used before feeding metabolizable energy assessment in broilers.Previous studies have shown that fasting cause atrophy of the intestinal villus.Whether fasting affects intestinal permeability during refeeding by altering barrier function and nutrient absorption is of concern.Here,23-d-old broilers were randomly assigned to 5 treatments,fasted for 0,12,24,36,and 48 h,respectively,and then refed for 2 d,to study the impact of different duration of fasting on the intestinal regeneration and barrier function during refeeding.Results showed that the intestinal morphology in fasted birds was recovered in 2 d of refeeding at most.As fasting durations increased,enterocytes per intestinal villus were linearly and quadratically increased(both P<0.05),whereas goblet cells per intestinal villus was linearly decreased(both P<0.05).Besides,the mRNA level of lysozyme was linearly decreased as fasting durations increased during refeeding(both P<0.05),while quadratically increased mucin 2 was observed only after 1 d of refeeding(P<0.05).Linear increase effects were observed for claudin 2 and zonula occludens-1with increased fasting durations after 1 d of refeeding(all P<0.05),and linear and quadratical effects were observed for claudin 2 at 2 d of refeeding(both P<0.05).Besides,we found that intestinal permeability to creatinine,4 and 70 kD dextran were linearly and quadratically decreased with increased fasting durations at 6 h and 1 d of refeeding(all P<0.05).Furthermore,jejunum proteomic from birds refed for 6 h showed that birds fasted for 36 h showed increased antimicrobial peptides and upregulated retinol metabolism when compared to the nonfasted birds(P<0.05).Further study showed that retinyl ester catabolism was inhibited during fasting and enhanced during refeeding.Results of intestinal organoid culture showed that retinol benefits the cell proliferation and enterocyte differentiation.In conclusion,the intestinal permeability to small and large molecules was decreased during refeeding by strengthening the intestinal barrier function,and the activated retinol metabolism during refeeding is involved in the intestinal regeneration and strengthens the intestinal barrier.

Large‑scale transcriptomic and genomic analyses reveal a novel functional gene SERPINB6 for chicken carcass traits

Background Carcass traits are crucial indicators of meat production efficiency.However,the molecular regulatory mechanisms associated with these traits remain unclear.Results In this study,we conducted comprehensive transcriptomic and genomic analyses on 399 Tiannong partridge chickens to identify key genes and variants associated with carcass traits and to elucidate the underlying regulatory mechanisms.Based on association analyses with the elastic net(EN)model,we identified 12 candidate genes(AMY1A,AP3B2,CEBPG,EEF2,EIF4EBP1,FGFR1,FOXD3,GOLM1,LOC107052698,PABPC1,SERPINB6 and TBC1D16)for 4 carcass-related traits,namely live weight,dressed weight,eviscerated weight,and breast muscle weight.SERPINB6 was identified as the only overlapping gene by 3 analyses,EN model analysis,weighted gene co-expression network analysis and differential expression analysis.Cell-level experiments confirmed that SERPINB6 promotes the proliferation of chicken DF1 cells and primary myoblasts.Further expression genome-wide association study and association analysis indicated that rs317934171 is the critical site that enhances SERPINB6 expression.Furthermore,a dual-luciferase reporter assay proved that gga-miR-1615 targets the 3′UTR of SERPINB6.Conclusions Collectively,our findings reveal that SERPINB6 serves as a novel gene for chicken carcass traits by promoting fibroblast and myoblast proliferation.Additionally,the downstream variant rs317934171 regulates SERPINB6 expression.These results identify a new target gene and molecular marker for the molecular mechanisms of chicken carcass traits.

A novel live attenuated vaccine candidate protects chickens against subtype B avian metapneumovirus

Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the dominant epidemic strain in China. We developed an attenuated aMPV subtype B strain by serial passaging in Vero cells and evaluated its safety and efficacy as a vaccine candidate. The safety test showed that after the 30th passage, the LN16-A strain was fully attenuated, as clinical signs of infection and histological lesions were absent after inoculation.The LN16-A strain did not revert to a virulent strain after five serial passages in chickens. The genomic sequence of LN16-A differed from that of the parent wild-type LN16(wtLN16) strain and had nine amino acid mutations. In chickens, a single immunization with LN16-A induced robust humoral and cellular immune responses, including the abundant production of neutralizing antibodies, CD4^(+) T lymphocytes, and the Th1(IFN-γ) and Th2(IL-4 and IL-6)cytokines. We also confirmed that LN16-A provided 100% protection against subtype B aMPV and significantly reduced viral shedding and turbinate inflammation. Our findings suggest that the LN16-A strain is a promising live attenuated vaccine candidate that can prevent infection with subtype B aMPV.

Endoplasmic reticulum stress improved chicken tenderness,promoted apoptosis and autophagy during postmortem ageing

In this study,endoplasmic reticulum(ER)stress inducer tunicamycin(TM)and inhibitor 4-phenylbutyric acid(4-PBA)were used to treat postmortem chicken breast muscle to investigate changes in tenderness and effects on apoptosis and autophagy during 5 days ageing.TM-induced ER stress reduced shear force,enhanced myofibril fragmentation index(MFI),disrupted myofibril structure,increased desmin degradation,and activatedμ-calpain and caspase-12.In addition,TM-induced ER stress increased the expression of Bax,Bim,and cytochrome c,and decreased the expression of Bcl-x L.Furthermore,TM-induced ER stress improved the conversion of LC3I to LC3II,raised the expression of Beclin-1,and decreased the expression of p62,PI3K,and m TOR.The opposite results were observed after 4-PBA treatment.These results suggested that ER stress could improve chicken tenderness,promote apoptosis and autophagy during chicken postmortem ageing.

Significant genomic introgression from grey junglefowl(Gallus sonneratii)to domestic chickens(Gallus gallus domesticus)

Background Chicken is one of the most numerous and widely distributed species around the world,and many studies support the multiple ancestral origins of domestic chickens.The research regarding the yellow skin phenotype in domestic chickens(regulated by BCO2)likely originating from the grey junglefowl serves as crucial evidence for demonstrating the multiple origins of chickens.However,beyond the BCO2 gene region,much remains unknown about the introgression from the grey junglefowl into domestic chickens.Therefore,in this study,based on wholegenome data of 149 samples including 4 species of wild junglefowls and 13 local domestic chicken breeds,we explored the introgression events from the grey junglefowl to domestic chickens.Results We successfully detected introgression regions besides BCO2,including two associated with growth trait(IGFBP2 and TKT),one associated with angiogenesis(TIMP3)and two members of the heat shock protein family(HSPB2 and CRYAB).Our findings suggest that the introgression from the grey junglefowl may impact the growth performance of chickens.Furthermore,we revealed introgression events from grey junglefowl at the BCO2 region in multiple domestic chicken breeds,indicating a phenomenon where the yellow skin phenotype likely underwent strong selection and was retained.Additionally,our haplotype analysis shed light on BCO2 introgression event from different sources of grey junglefowl into domestic chickens,possibly suggesting multiple genetic flows between the grey junglefowl and domestic chickens.Conclusions In summary,our findings provide evidences of the grey junglefowl contributing to the genetic diversity of domestic chickens,laying the foundation for a deeper understanding of the genetic composition within domestic chickens,and offering new perspectives on the impact of introgression on domestic chickens.

Asymmetric expression of CA2 and CA13 linked to calcification in the bilateral mandibular condyles cause crossed beaks in chickens

Crossed beak is a complex mode of inheritance with prevalence ranging from 0.2 to 7.4% in at least 12 chicken strains worldwide.To reveal the intrinsic factors causing crossed beaks,genes expression patterns in bilateral mandibular condyle between affected and normal birds were characterized by RNA sequencing analysis in the present studies.Crossed beak was induced by short length of unilateral mandibular ramus,and a total of 110differentially expressed genes were up-or down-regulated in the affected(short)mandibular condyle side as compared to the normal side.Carbonic anhydrase 2(CA2)and Carbonic anhydrase 13(CA13)were enriched in the carbonate dehydratase activity,and high-expressed in mandibular condyle and osteoblasts(P<0.05).However,both were low-expressed in short mandibular condyle side of affected birds(P<0.05).The carbonate dehydratase inhibitor experiments confirmed that there is positive association between the calcification and carbonic anhydrase isoenzymes.Quantitative analysis with cetylpyridinium chloride showed a decrease in calcification when the cells were transfected with an anti-CA13 shRNA.Our research suggested that CA2 and CA13 are down-calcified in shortside mandibular condyle,and caused mandibular ramus to grow slowly.CA2 and CA13 have the critical role in crossed beaks by regulating calcification of mandibular condyle.

Proteo-transcriptomic profiles reveal key regulatory pathways and functions of LDHA in the ovulation of domestic chickens(Gallus gallus)

Background In poultry, the smooth transition of follicles from the preovulatory-to-postovulatory phase impacts egg production in hens and can benefit the poultry industry. However, the regulatory mechanism underlying follicular ovulation in avians is a complex biological process that remains unclear.Results Critical biochemical events involved in ovulation in domestic chickens(Gallus gallus) were evaluated by transcriptomics, proteomics, and in vitro assays. Comparative transcriptome analyses of the largest preovulatory follicle(F1) and postovulatory follicle(POF1) in continuous laying(CL) and intermittent laying(IL) chickens indicated the greatest difference between CL_F1 and IL_F1, with 950 differentially expressed genes(DEGs), and the smallest difference between CL_POF1 and IL_POF1, with 14 DEGs. Additionally, data-independent acquisition proteomics revealed 252 differentially abundant proteins between CL_F1 and IL_F1. Perivitelline membrane synthesis, steroid biosynthesis, lysosomes, and oxidative phosphorylation were identified as pivotal pathways contributing to ovulation regulation. In particular, the regulation of zona pellucida sperm-binding protein 3, plasminogen activator, cathepsin A, and lactate dehydrogenase A(LDHA) was shown to be essential for ovulation. Furthermore, the inhibition of LDHA decreased cell viability and promoted apoptosis of ovarian follicles in vitro.Conclusions This study reveals several important biochemical events involved in the process of ovulation, as well as crucial role of LDHA. These findings improve our understanding of ovulation and its regulatory mechanisms in avian species.

Layer chicken microbiota:a comprehensive analysis of spatial and temporal dynamics across all major gut sections

Background The gut microbiota influences chicken health,welfare,and productivity.A diverse and balanced microbiota has been associated with improved growth,efficient feed utilisation,a well-developed immune system,disease resistance,and stress tolerance in chickens.Previous studies on chicken gut microbiota have predominantly focused on broiler chickens and have usually been limited to one or two sections of the digestive system,under con-trolled research environments,and often sampled at a single time point.To extend these studies,this investigation examined the microbiota of commercially raised layer chickens across all major gut sections of the digestive system and with regular sampling from rearing to the end of production at 80 weeks.The aim was to build a detailed picture of microbiota development across the entire digestive system of layer chickens and study spatial and temporal dynamics.Results The taxonomic composition of gut microbiota differed significantly between birds in the rearing and pro-duction stages,indicating a shift after laying onset.Similar microbiota compositions were observed between proven-triculus and gizzard,as well as between jejunum and ileum,likely due to their anatomical proximity.Lactobacil-lus dominated the upper gut in pullets and the lower gut in older birds.The oesophagus had a high proportion of Proteobacteria,including opportunistic pathogens such as Gallibacterium.Relative abundance of Gallibacterium increased after peak production in multiple gut sections.Aeriscardovia was enriched in the late-lay phase compared to younger birds in multiple gut sections.Age influenced microbial richness and diversity in different organs.The upper gut showed decreased diversity over time,possibly influenced by dietary changes,while the lower gut,specifi-cally cecum and colon,displayed increased richness as birds matured.However,age-related changes were inconsist-ent across all organs,suggesting the influence of organ-specific factors in microbiota maturation.Conclusion Addressing a gap in previous research,this study explored the microbiota across all major gut sections and tracked their dynamics from rearing to the end of the production cycle in commercially raised layer chickens.This study provides a comprehensive understanding of microbiota structure and development which help to develop targeted strategies to optimise gut health and overall productivity in poultry production.

Major regulatory factors for reproductive performances of female chickens

The reproductive performance of female chickens is critical for determining the efficiency of production and productivity and thus profitability.Studies have shown that the reproductive performance of female chickens is mainly regulated by the feed,hormones,genes,and light conditions.Herein,we review the major factors regulating female chicken reproductive performance and assess the reproductive organs and their functions.In the current review,we highlight how the interconnections of hormones,candidate genes,and photo-stimulation regulate female chicken reproductive hormones and thus regulate the reproductive organ performance.In this regard,the roles of main hormones[gonadotropinreleasing hormone(GnRH)and genes(GnRH-Ⅰ)]in regulating sexual maturation and ovarian development and maintenance by influencing the survival and function of follicular granulosa cells were also reviewed.In addition,the current review also highlights how feeding female chickens with diets and artificial light-emitting diodes(LEDs)support the effective functioning of their reproductive capacity through the stimulation of sexual maturity at an appropriate age and regeneration of aged reproductive organs.