Free-range chicken eggs as a bioindicator of dioxin contamination in Vietnam,including long-term Agent Orange impact

PCDD/Fs contamination of free-range chicken eggs and soils from private Vietnam households was studied.The possibility of using free-range eggs as bio-indicators of dioxin contamination was considered as the soil-chicken-egg exposure pathway is considered to be the most sensitive exposure pathway of dioxins in soils to humans.A large territory from Dong Nai province in the south to Lao Cai province in the north was covered by the research.All analyses were performed by HRGC-HRMS method.PCDD/Fs levels in eggs from the majority of southern households exceeded the EC limit for eggs and egg products(2.5 pg WHO-TEQ2005 g^-1 lipid).Total TEQs ranged from 0.4 to 361 pg WHO-TEQ2005 g^-1 lipid in eggs and from 0.1 to 1272 pg WHO-TEQ2005/g in soil.2,3,7,8-TCDD contribution was statistically significantly higher in both eggs and soils in sprayed with Agent Orange areas,indicating its long-term impact.In order to assess within site variation,a total of 62 individual eggs from 14 private households were analyzed.Mean relative standard deviation of total TEQ values in individual eggs within the separate households was 27%.Rather good correlation of PCDD/Fs concentration in eggs and respective soils was observed for all dioxin congeners and for hexa-and hepta-furans(except for 1,2,3,7,8,9-HxCDF).Higher bioaccumulation for lower chlorinated congeners was confirmed.The current study of using eggs as bioindicators for large POPs contaminated sites may be suggested as a policy approach to evaluate human exposure to dioxin/POPs contaminated sites for known or suspected contaminated areas.

Comparative Analysis of Slaughter Performance and Meat Flavor Traits of Quality Chicken under Cage Rearing and Free-range Farming Conditions

[Objective]The paper was to compare the slaughter performance and meat flavor of quality chicken under cage rearing and free-range farming conditions.[Method]A total of 4001-day-old cocks,S07 line cultivated by Sichuan Dahen Poultry Breeding Co.,Ltd.(bred for 4 succes-sive generations),were kept in cages until the end of 5 weeks of age,which were then divided into cage rearing and free-range farming groups.All cocks were fed with the same diet,and slaughter tests and meat quality analysis were carried out at the end of 10 and 22 weeks of age,respectively.[Result]The live weight,carcass weight and abdominal fat percentage in cage rearing group were significantly higher than those in free-range farming group(P<0.01),and the percentage of half-eviscerated yield and percentage of eviscerated yield in cage rearing group were significantly higher than those in free-range farming group(P<0.05),but there were no significant differences in dressing percentage,percentage of leg muscle and per-centage of breast muscle.The intramuscular fat(IMF)content and muscle fiber density of chicken in cage rearing group were significantly higher than those in free-range farming group(P<0.01),but there was no significant difference in inosinic acid(IMP)content.The content of IMF and IMF increased with the increase of feeding age,but the deposition rate of intramuscular fat was higher than that of IMF in late feeding period.[Conclusion]The study will provide reliable guidance for production and market consumption of high quality chicken.

<i>Campylobacter, Salmonella</i>and <i>Escherichia coli</i>Food Contamination Risk in Free-Range Poultry Production System

Livestock such as poultry is consumed as food worldwide and it constitutes one of the main protein sources for diners, as well as an important source of revenue generation for farmers. Poultry meat production chain identifies a significant role of the farm to folk. Most often, the systems used in poultry production can result in a higher prevalence of Campylobacter, Salmonella, and Escherichia coli contamination, leading to adverse health effects with detrimental consequences. The method of poultry keeping plays a significant role in the poultry meats’ outcome and its food safety standards. Farmers attempt to develop new poultry operations, however, there are two main possibilities;to operate within the present vertically integrated system which is incredibly good for disease prevention and to develop independently, or a smaller operation that is more animal friendly. This article reviews the available research on the impact of free-range poultry production systems on food safety, most importantly the prevalence and control of Campylobacter, Salmonella and Escherichia coli in free-range production systems. The results suggest a conflicting view when bacterial loads of poultry meat from conventional and free-range systems are compared. Studies have shown increased bacterial loads in a free-range production system.

An Evaluation of the Infection Status and Source of Subgroup J Avian Leukosis Virus in Cloned Free-Range Layers

In recent years, subgroup J avian leukosis virus （ALV-J） has been found to frequently infect layers in China. This virus is responsible for economic losses due to both mortality and decreased performance in chickens. In this study, 45-d-old cloned flee-range layers were suspected to be infected with ALV and other immunosuppressive diseases because their feathers were unkempt and their growth rate was impaired. To estimate the infection status and determine the source of ALV-J in the flock, 30 cloacal swabs were randomly collected to measure the p27 antigen level by enzyme-linked immunosorbent assay （ELISA）. Among the birds that were tested, 87% （26/30） were positive. In addition, 6 anticoagulant blood samples were aseptically collected at random from the flock when the layers were 60 d old. These samples were centrifuged to obtain the leukocytes, which were then used to inoculate chicken embryo fibroblast （CEF） cells for the identification of ALV-J by indirect immunofluorescence （IFA）. Of the samples tested, 100% （6/6） were positive. The flock＇s production performance was also investigated, and 10 layers were necropsied to evaluate pathological changes at 115 d of age. The flock never laid eggs even though they reached the age of the first laying （110 d）. Furthermore, there were pathological changes present, including atrophy of the thymus and bursa of Fabricius, undeveloped ovaries, glandular stomach haemorrhage, and hepatosplenomegaly. Paraffin-embedded sections of intumescent liver and spleen were prepared for antigen localisation using IFA. Positive signals were prevalent in paraffin-embedded sections of the intumescent liver and spleen. Furthermore, provirus DNA was extracted from 4 cloned flee-range layers, and 2 patemal parents （HR native cocks）, and the gp85 gene of ALV-J was amplified by PCR to analyse the genetic variation. The results of the autogenous variation analysis showed that the 6 strains were 98.5-99.7% homologous. This study indicated that there was persistent infection with ALV-J by dynamic inspection, which seriously reduced the production performance of the flock. In addition, the genetic variation analysis showed that ALV-J in the flock was more likely to have originated from the paternal parent, the HR native cock.

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.

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.

Amino Acid and Mineral Composition of Meat from Free-range Broilers Reared on Alpine Steppe

An increasing number of consumers demanding health foods have favoured poultry meat from natural production system. Amino acid and mineral elements are essential nutrient, required for numerous metabolic functions, which are provided partly by the poultry. The objective of this study was to evaluate amino acid and mineral composition in meat of free-range broilers fed on grasshoppers on alpine rangeland in the Tibetan Plateau. Eighty, 28-day-old Qinjiaoma male broilers were introduced into a rangeland where there was a dense population of grasshoppers （treatment GC）. Control chicken were reared under intensive condition and given a maize-soybean diet （treatment CC）. At 91 days of age, 24 birds from each treatment were slaughtered. Fresh breast meats were packaged and refrigerated for determination. The results indicated that dietary grasshoppers and rearing condition significantly （P 〈 0.05） affected some amino acid and mineral elements composition. Aspartic, arginine, threonine, isoleucine and lysine were higher in the muscles from GC than those from CC, and the similar trend were also found in the content of total amino acid and essential amino acid. While tryptophan and methionine were lower （P 〈 0.05） in meat from GC than that from CC. Effect of diets and rearing condition on mineral elements was also observed, the concentration of sodium, phosphorus and iron were higher （P 〈 0.05） in muscle from GC, while calcium was higher in muscle from CC. In conclusion, the meat in free-range broilers fed on grasshoppers has the richer amino acid and mineral elements.

Technical Measures for High Quality and High Yield of Free-range Sows in Rural Areas

Today,with the rapid development of modern and large-scale pig industry,free-range pig farming is still an important part of the breeding industry.Different from large-scale pig farms,there are many shortcomings in feeding management,pig disease prevention and control and so on for small-scale farmers.In the long-term clinical diagnosis and production practice,it is found that sows raised by small-scale farmers often have some problems,such as non-estrus,repeated infertility and"false pregnancy",weak farrowing,stillbirth,and postpartum piglet death.This paper makes a comprehensive analysis on the performance and etiology of the above-mentioned free-range sows,and puts forward the corresponding prevention and control measures,in order to provide a theoretical basis for the feeding and management of rural free-range sows.

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.

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.

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.

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.

Dietary Macleaya cordata extract supplementation improves the growth performance and gut health of broiler chickens with necrotic enteritis

Background The poultry industry needs effective antibiotic alternatives to control outbreaks of necrotic enteritis(NE)caused by Clostridium perfringens.Methods The aim of this study was to investigate the effects of dietary supplementation with Macleaya cordata extract(MCE)on the immune function and gut microbiota of broilers with NE.A total of 2881-day-old broiler chicks were randomly assigned to a 2×2 factorial arrangement with two concentrations of dietary MCE supplementation(0 or 350 mg/kg of diet)and two disease challenge statuses(control or NE).Results The results revealed that NE significantly increased the feed conversion rate(FCR),mortality,intestinal lesion score,the levels of IL-1β,IL-17 and IFN-γ/IL-4 in serum and IL-17/IL-10 in the jejunal mucosa,m RNA levels of TLR2,IFN-γand p Ig R in the jejunum,and Clostridium perfringens concentrations in the cecum.NE significantly decreased the body weight(BW),body weight gain(BWG),jejunal villus height,V/C,m RNA level of AMPK-α1 in jejunum,IL-4 level in the jejunal mucosa and lactic acid bacteria abundance in the cecum.MCE significantly increased BW,BWG,jejunal villus height,V/C,m RNA levels of occludin,ZO-1 and AMPK-α1 in the jejunum,the levels of Ig A and Ig G in serum and IL-10 in the jejunal mucosa and m RNA levels of NF-κB,IL-10 and MHC-II in the jejunum.Additionally,MCE significantly decreased the FCR,mortality,intestinal lesion score,jejunal crypt depth,the levels of IFN-γand IL-17 in serum and IL-17/IL-10 in the jejunal mucosa,Clostridium perfringens concentrations in the cecum,and m RNA levels of IL-17/IL-10 in the jejunum.Moreover,NE significantly increased the abundance of bacteria that are associated with inflammation,obesity and depression(Alistipes,Barnesiella,Intestinimonas,RF39 and UCG-005)and significantly decreased the abundance of short-chain fatty acid(SCFA)-producing bacteria(Anaerotruncus,Butyricicoccus and Bacteroides)in the cecum.MCE significantly increased the abundance of SCFA-producing bacteria(Streptococcus,Ruminococcus_torques_group and Lachnospiraceae_NK4A136_group)and significantly reduced the abundance of bacteria that are associated with inflammation and obesity(Alistipes,Barnesiella and UCG-010)in the cecum.In the cecum of broilers with NE,the relative abundance of Barnesiella and Alistipes was higher and that of Lachnoclostridium and Shuttleworthia was lower.Interestingly,these trends were reversed by the addition of MCE to the diet.Spearman correlation analysis showed that Barnesiella and Alistipes were associated with enhanced intestinal inflammation and inhibited growth performance,whereas Lachnoclostridium and Shuttleworthia were associated with anti-inflammatory effects.Conclusions MCE ameliorated the loss of growth performance in broiler chickens with NE,probably by regulating the intestinal barrier,immune function,and gut microbiota.