Chicken Breeds Research Articles

Protective Effect of a Hyperimmune Serum Against Homologous Enterococcus cecorum Infection in Experimentally Challenged Meat-Type Chickens

Knowledge about chickens’ immune response to infection with Enterococcus cecorum (EC) and prophylactic strategies is scarce. This study aimed to investigate the protective effect of an EC-specific hyperimmune serum after experimental challenge with homologous EC. A total of 284 one-day-old meat-type chickens were randomly assigned to three groups (non-inoculated (C), passively immunized with hyperimmune serum and EC-inoculated (EPI), and EC-inoculated (E)). At 1 and 2 days post-hatch (dph), the hyperimmune serum was subcutaneously administered to each chicken in group EPI. Oral inoculation with EC was carried out at 2 dph. Blood samples and cloacal swabs were collected at 7, 14, 21, 28, and 35 dph and necropsy was carried out at 42/43 dph. Extraintestinal colonization with EC was significantly decreased in group EPI compared to group E. Additionally, femoral head necrosis and spondylitis of the free thoracic vertebra were significantly decreased in group EPI compared to group E. Flow cytometric analysis revealed a significant increase in heterophils, monocytes, and the heterophil/lymphocyte ratio in the peripheral blood of bacteriological positive chickens. Although the parenteral application of a hyperimmune serum lacks practicability in meat-type chicken flocks, the results of this study encourage further research on vaccination of meat-type chicken breeder flocks.

Maternal derived antibodies and avian β-defensins expression patterns and their correlation in the yolk sac tissue of different chicken breeds (Gallus gallus).

The expression of maternal derived antibodies (MDAs) and avian β-defensins (AvBDs) in yolk sac tissue may be age-specific and influenced by breed, thereby immunological window difference in hatchlings. This study investigated the mRNA expression of MDAs and AvBDs in the yolk sac tissues of Beijing You and Hy-Line Gray chickens from the embryonic day (ED)7 to 3 days after hatch (DAH). Hy-Line showed a higher embryo bodyweight and a lower residual yolk weight at ED17 (P < 0.05). The expression of IgY and FcRY was higher in the Hy-Line (P < 0.05). In Beijing You, IgA level decreased from ED15 to 19 but peaked from day old hatch to 3 DAH. In Hy-Line, IgA increased from ED19 to 3 DAH (P < 0.05). IgY increased from ED17 to day old hatch (DOH), but declined from DOH to 3 DAH in Beijing You, whereas in Hy-Line, it declined from ED9 to 15 and ED19 to 3 DAH (P < 0.05). FcRY expression declined from DOH to 3 DAH in Beijing You and from ED19 to 3 DAH in Hy-Line (P < 0.05). The expression of AvBD5 increased from ED7 to 13 and ED19 to 3 DAH, and decreased from ED13 to 19 in both breeds. A similar expression patterns of AvBD10 was observed in breeds, increased from ED7 to 11, followed by a decline after ED11. AvBD12 expression peaked at ED17 in Beijing You and from ED15 to 17 in Hy-Line (P < 0.05), then declined from ED17 to 3 DAH in both breeds. The study observed temporal expression development patterns of AvBD5 and AvBD10 in both breeds and AvBD12 in Beijing You, with a correlation coefficient of R2 > 0.5. Overall, the lower yolk residue for faster growth of chickens compromised the expression of MDAs and AvBDs, except for IgA and AvBD5. These results suggest a broader immunological window and highlight the need to focus on maintaining specific MDAs and AvBDs in the strategies of embryonic feeding.

Functional analysis of key members affecting egg production in the transglutaminase gene family in chickens.

The transglutaminase (TGMs) family plays a crucial role in regulating mammalian reproduction, yet its impact on poultry reproductive traits has not been extensively studied. In this study, we identified eight members of the TGMs family in chickens and examined the contributions of genetic variations of coagulation factor XIII A chain (F13A1), transglutaminase 4 (TGM4), and LOC101749664 to selective breeding in commercial layers through genetic variation response pattern analysis. Transcriptome data from various tissues of high- and low-egg-yielding Gushi chickens revealed significant positive correlations between the mRNA expression levels of TGM4 and F13A1 genes and egg production (P < 0.05). Genotype-phenotype correlation analysis showed that 26 single nucleotide polymorphisms (SNPs) within genomic sequences of TGM4 and F13A1 genes exhibited significant associations with egg production traits across different laying periods. Additionally, spatiotemporal expression patterns of TGM4 in ovarian follicles between high- and low-laying chicken breeds determined by RT-qPCR highlighted the pivotal role of TGM4 in follicle development. Functionally, the gain-of-function assay demonstrated that TGM4 promoted granulosa cell proliferation, inhibited apoptosis, and enhanced progesterone synthesis. In conclusion, this is the first study to elucidate the role of the TGMs gene family in regulating egg production in chickens, offering new insights for the selective breeding of layers with improved egg-laying traits.

Genomic Prediction and Genome-Wide Association Study for Growth-Related Traits in Taiwan Country Chicken

Taiwan Country chickens are integral to Taiwanese culture and the poultry industry. By establishing a crossbreeding system, breeders must consider the growth-related traits of the dam line to achieve acceptable traits in commercial meat-type chickens. This study compared the accuracy of genomic estimated breeding values (GEBVs) predicted using the pedigree-based best linear unbiased prediction (PBLUP) model and the single-step genomic BLUP (ssGBLUP) model. Additionally, we conducted a genome-wide association study (GWAS) to identify single-nucleotide polymorphisms (SNPs) associated with growth, shank, and body conformation traits to support marker-assisted selection (MAS). The results showed that the ssGBLUP model achieved 4.3% to 16.4% higher prediction accuracy than the PBLUP model. GWAS identified four missense SNPs and four significant SNPs associated with body weight, shank length, and shank width at 12 weeks. These findings highlight the potential of integrating the ssGBLUP model with identified SNPs to improve genetic gain and breeding efficiency and provide preliminary results to assess the feasibility of genomic prediction and MAS in Taiwan Country chicken breeding programs. Further research is necessary to validate these findings and explore their mechanisms and broader application across different breeding programs, particularly for the NCHU-G101 breed of Taiwan Country chickens.

Recombinant nanobody expressed by transgenic chimeric chickens eliminated vertical transmission of avian leukosis virus subgroup J.

Because of the vertical transmission of avian leukosis virus subgroup J (ALV-J), control of ALV-J in breed of chicken is still a serious issue. Blocking vertical transmission using antibodies is a potential strategy, but its high cost limits its application. We artificially designed recombinant nanobody (Nb) and efficiently expressed and secreted them in three primary chicken cells cultured in vitro by adenovirus delivery. We found that secreted the Nb could reduce the infection of cells by ALV-J. Moreover, we prepared transgenic chimeric chickens expressing Nb and found that the Nb reduced the infection and vertical transmission of ALV-J to chickens. In particular, transgenic chimeric hens expressing high concentration of the Nb eliminated vertical transmission of the virus. Collectively, current study provides new avenues for the control of ALV-J transmission.

Characterization of TCRβ and IGH Repertoires in the Spleen of Two Chicken Lines with Differential ALV-J Susceptibility Under Normal and Infection Conditions

This study investigates the immunological factors underlying the differential susceptibility of two chicken strains, E- and M-lines, to avian leukosis virus subgroup J (ALV-J). During the eradication of avian leukosis at a chicken breeder farm in Guangdong, we observed strain-specific differences in susceptibility to ALV-J. Moreover, E-line chickens exhibited a slower antibody response to ALV-J compared to M-line chickens. As the T cell receptor (TCR) and B cell receptor (BCR) are critical for antigen recognition, their activation triggers specific immune responses, including antibody production. Using high-throughput sequencing, we characterized the T cell receptor beta (TCRβ) and immunoglobulin heavy chain (IGH) repertoires in spleen tissues from both chicken strains. The M-line demonstrated higher clonal diversity in both TCRβ and IGH repertoires under normal conditions compared to the E-line, suggesting a broader baseline antigen recognition capacity. Following ALV-J infection, the TCRβ repertoire diversity remained unchanged, while the IGH repertoire displayed distinct clonal expansion patterns and complementarity-determining region 3 (CDR3) length distributions between the two lines, potentially affecting their ability to recognize ALV-J antigens. Our study provides the first comprehensive comparison of TCRβ and IGH repertoire dynamics in chickens with different ALV-J susceptibilities, offering new insights into the molecular and immunological mechanisms underlying resistance to ALV-J.

Decoding the chicken gastrointestinal microbiome

Metataxonomic studies have underpinned a vast understanding of microbial communities residing within livestock gastrointestinal tracts, albeit studies have often not been combined to provide a global census. Consequently, in this study we characterised the overall and common ‘core’ chicken microbiota associated with the gastrointestinal tract (GIT), whilst assessing the effects of GIT site, bird breed, age and geographical location on the GIT resident microbes using metataxonomic data compiled from studies completed across the world. Specifically, bacterial 16S ribosomal DNA sequences from GIT samples associated with various breeds, differing in age, GIT sites (caecum, faeces, ileum and jejunum) and geographical location were obtained from the Sequence Read Archive and analysed using the MGnify pipeline. Metataxonomic profiles produced across the 602 datasets illustrated the presence of 3 phyla, 25 families and 30 genera, of which core genera (defined by presence in over 90% of datasets) belonged to Lactobacillus, Faecalibacterium, Butyricicoccus, Eisenbergiella, Subdoligranulum, Oscillibacter, Clostridium & Blautia. PERMANOVA analysis also showed that GIT site, bird breed, age and geographical location all had a significant effect on GIT microbial diversity, regardless of dietary factors, which were not considered in this study. On a genus level, Faecalibacterium was most abundant in the caeca, Lactobacillus was most abundant in the faeces, ileum and jejunum, with the data showing that the caeca and faeces were most diverse. AIL F8 progeny, Ross 308 and Cobb 500 breeds GIT bacteria were dominated by Lactobacillus, and Eisenbergiella, Megamonas and Bacteroides were most abundant amongst Sasso-T451A and Tibetan chicken breeds. Microbial communities within each GIT site develop with age, from a Lactobacillus and Streptococcus dominated community during the earlier stages of growth, towards a Faecalibacterium, Eisenbergiella, Bacteroides, Megamonas, and Lactobacillus dominated community during the later stages of life. Geographical locations, and thus environmental effectors, also impacted upon gastrointestinal tract microbiota, with Canadian and European datasets being dominated by Lactobacillus, whilst UK and Chinese datasets were dominated by Eisenbergiella and Bacteroides respectively. This study aids in defining what ‘normal’ is within poultry gastrointestinal tract microbiota globally, which is imperative to enhancing the microbiome for productive and environmental improvements.

Avian haemosporidian parasites affecting non-descript village chickens in Africa

Smallholder farmers in most of the rural areas in African countries rear non-descript village chickens for petty cash, food provision and for performing rituals. Village chicken production systems are regarded as low input- low output because the chickens receive minimum care and produce average to less eggs and meat. The chickens receive minimal biosecurity and are often left to scavenge for feed and thus exposes them to potential vector parasites that can transmit parasites such as haemoparasites. Haemosporidian parasites (Haemosporidia, Apicomplexa) are blood parasites infecting avian species, especially chickens. They are transmitted by blood sucking vectors such as biting midges, mosquitoes, black flies and louse flies. Infections are mild to severe causing reproduction, production and health losses such as decreased fertility, reduced body weight and egg production, anaemia and inflammation of vital organs such as the liver and spleen. Haemoparasites infections in chickens can be lowered through controlling vector parasites and the use of antimalarial drugs on exotic chicken breeds. The aim of this review is to characterize the avian haemosporidian parasites affecting non-descript village chickens in Africa, describing their morphology, life cycle, pathogenicity, control and prevention measures.

Matrix metalloproteinase 7 (MMP7) as a molecular target for Mycoplasma gallisepticum (MG) resistance in chickens.

Mycoplasma gallisepticum (MG) causes chronic respiratory disease (CRD), posing a significant threat to global poultry production. Current preventive strategies face limitations, emphasizing the need for alternative approaches such as breeding for disease resistance. This study identifies the matrix metalloproteinase 7 (MMP7) gene as a key factor in CRD resistance. Analysis of high-throughput sequencing data revealed MMP7's association with MG infection at tissue and cellular levels. Overexpression of MMP7 in avian type II alveolar epithelial cells (AECII) and macrophages (HD11) inhibited MG adhesion, modulated immune responses, and suppressed MG-induced cell proliferation and apoptosis, though MG replication remained unaffected. Conversely, MMP7 inhibition enhanced MG infection. Experimental infections in commercial (Jingfen Layer No.6, Hy-Line White) and local Chinese chicken breeds (Guangxi Indigenous, Tianlu Partridge, Cyan Shank Partridge) validated Tianlu Partridge chickens' relative resistance and Jingfen Layers' susceptibility. MMP7 expression levels correlated positively with reduced chick weight, air sac damage, tracheal mucosal thickness, and MG lung loads. These findings highlight MMP7 as a molecular target for assessing MG susceptibility and breeding resistant chickens while demonstrating the utility of local Chinese breeds in resistance-focused breeding programs.

Genome Sequencing Reveals the Adaptation of Chickens to High Altitudes in Different Regions.

Altitudinal adaptation is a key factor in species formation and leads to increased species diversity. Chickens are one of the most widely distributed and important domesticated species, making them ideal models for studying the evolution of altitudinal adaptation. Therefore, we downloaded and analyzed the total genome data of 160 individual chickens from seven sampling regions at two different altitudes (>3000 m and <600 m). In total, 21,672,487 high-quality single-nucleotide polymorphisms were selected and used for subsequent analyses. First, we interpreted the genetic relationships among chickens from different sampling regions using a neighbor-joining tree, population structure, and four dimensionality reduction methods. We found that 38 genes were significantly associated with altitudinal adaptations by FST and θπ. Functional annotation of the genes showed that they are primarily involved in energy metabolism, ion channel activity, and blood pressure regulation. Our results provide evidence of genetic diversity among different chicken breeds and reveal the mechanisms of adaptation to high altitudes.

Multi-Omics Insights into Regulatory Mechanisms Underlying Differential Deposition of Intramuscular and Abdominal Fat in Chickens.

Excessive abdominal fat deposition in chickens disadvantages feed conversion, meat production, and reproductive performance. Intramuscular fat contributes to meat texture, tenderness, and flavor, serving as a vital indicator of overall meat quality. Therefore, a comprehensive analysis of the regulatory mechanisms governing differential deposition of abdominal versus intramuscular fat is essential in breeding higher-quality chickens with ideal fat distribution. This review systematically summarizes the regulatory mechanisms underlying intramuscular and abdominal fat traits at chromatin, genomic, transcriptional, post-transcriptional, translational, and epigenetic-modification scales. Additionally, we summarize the role of non-coding RNAs and protein-coding genes in governing intramuscular and abdominal fat deposition. These insights provide a valuable theoretical foundation for the genetic engineering of high-quality and high-yielding chicken breeds.

Modulation of growth-related protein expression of native chicken in low altitude in West Jawa, Indonesia

Objective: The objective of this study was to evaluate the response-ability of local chickens to their rearing habitat, especially at low altitudes, to comprehensively understand the cellular response related to protein growth. Materials and Methods: Studies of cellular responses related to modulation and growth-related protein salinization for three local Indonesian chicken breeds to low altitudes with high temperatures have been conducted in two locations with altitudes &lt;55 m above sea level. Three hundred local chickens, each consisting of one hundred Sentul, Kedu, and Pelung chickens. During the study, chickens were kept in an intensive system with litter control, equipped with access to play. Blood samples were collected following all standard procedures at the end of the study. Analysis of blood samples has been carried out based on procedures by the protocol on the BioSource KIT and Randox KIT. Results: Based on the results of the current study, it appears that the overall cellular response of three local chicken breeds shows differences. Sentul chicken and Pelung chicken have better cellular protein expression responses than Kedu chicken. However, when it comes to body weight growth, it seems that protein irradiation to growth is better in Kedu chicken. Conclusion: The results of the study showed that low altitude with high ambient temperature was better able to be responded to by Kedu chickens, while Sentul and Pelung chickens resulted in both experiencing metabolite shocks, which can be characterized by increased alternative energy provision with creatine phosphate change activity.

Genome-Wide Association Study of Myofiber Type Composition Traits in a Yellow-feather Broiler Population

Meat quality is a key factor determining the economic viability of the broiler industry, particularly in native broiler breeds. Skeletal muscles contain a mixture of muscle fibers, each possessing unique physicochemical properties; the composition of myofiber types within these muscles is closely linked to meat quality. However, comprehension of the regulatory mechanisms governing this trait remains limited. Therefore, we conducted a genome-wide association study (GWAS) with a population of 400 yellow-feather broilers to explore genetic variations associated with myofiber-type composition at the genomic level. Whole-genome resequencing was employed to detect genetic variations and immunohistochemistry was used for muscle fiber typing in the sartorius muscle. We identified 1 and 18 single-nucleotide polymorphisms (SNPs) significantly and potentially associated with the proportion of slow muscle fibers, respectively, and 1 and 12 SNPs significantly and potentially associated with the area proportion of slow muscle fibers, respectively. We annotated several candidate genes, including DMD, KLF7, CREB1, EFCAB11, GADD45A, GSTT1, and GSTT1L, which are related to myofiber type composition. We also demonstrated that myofiber composition traits exhibit low-to-medium heritability, indicating potential for enhancement through genetic selection. These findings provide a crucial reference for further studies on the regulatory mechanisms of poultry meat quality and for advancing the breeding of superior-quality broiler chickens.

Effects of Formula Product Injection on Hatching Parameters, Small Intestinal Development and Ileum Histology in Breeder Chicken Eggs.

This study aimed to determine the effects of in ovo formula product injection on hatching parameters, chick quality, small intestinal development and ileum histology of breeder hen eggs. A total of 400 fertilised eggs were obtained from the Atak-S parent flock at 42 weeks of age for the experiment. The experiment was designed in two groups: a control group (C), in which no injection was performed, and the other group in which a solution containing formula products at concentrations of 1.25% (F1), 2.5% (F2) and 5% (F3) was injected into 0.5mL/egg air sac. The hatching rate, embryonic mortality and discard chick rate were examined at the end of the trial. The best result of the hatching rate was found in the Group F2, while there was no difference between the control and Group F1 regarding these parameters. The weight and length of the quality chicks were promoted in the Group F1. In Group F3, the injection of the formula product at a rate of 5% had a negative effect on parameters such as hatchability, embryonic mortality, chick length, Pasgar score and yolk sac weight compared to the other groups. Otherwise, in Group F2, there was a significant increase in villus height, crypt depth and lamina muscularis mucosa thickness compared to the other groups (p<0.01). As a result, it has been concluded that the appropriate rates for the formula product application on chicks are 1.25% and 2.5%, considering the positive effects of the 1.25% and 2.5% rates and the negative effects of the 5% rate.

Polymorphism of the prolactin gene and its association with reproductive traits in F2 local crossed chickens

Background and Aim: Reproductive traits are crucial for genetic improvement in chickens. Prolactin (PRL) is a gene involved in a complex hormonal network that regulates reproduction in chickens. In this study, three local chicken breeds were crossed and had been produce a second filial (F2) generation, referred to as the F2 local crossed chicken. This study aimed to evaluate reproductive traits, identify single-nucleotide polymorphisms (SNPs), and assess genetic variation in the PRL gene of F2 local crossed chickens. Materials and Methods: Data on reproductive traits, including body weight (BW) at first egg laying, total egg production (EP) at 90 days of age, egg weight (EW), egg length (EL), and egg width (EWd), and blood samples from 60 hens of F2 local crossed chicken (Merawang × Kampung Unggul Balitbangtan [KUB], n= 30; Murung Panggang × KUB [MP × KUB], n= 30) were collected. SNPs within PRL gene were identified using BioEdit version 7.0. Genetic diversity was calculated using Popgen 1.32. Statistical analysis of reproductive traits and its association with genotypes were assessed using Statistical Product and Service Solutions version 20. Results: Crossing patterns had no significant effect on reproductive traits (p &gt; 0.05), except for EWd (p &lt; 0.05). Five polymorphic SNPs were identified in exon 5 of the PRL gene: 8052T&gt;C, 8113G&gt;C, 8187C&gt;T, 8188G&gt;A, and 8321C&gt;T. Observed and expected heterozygosity range from 0.15–0.52 and 0.14–0.38, respectively. All SNPs were in the Hardy-Weinberg equilibrium based on Chi-square test (χ2 &lt;3.841), except for SNP 8052T&gt;C in F2 crossing of MP × KUB. SNP 8052T&gt;C was significantly associated with BW (p &lt; 0.05), with TT genotype chickens showing higher BW. SNP 8187C&gt;T was associated with EW and EL (p &lt; 0.05), with CT genotype chickens having higher values for both traits. Conclusion: This study demonstrates the significant role of the PRL gene in influencing reproductive traits in F2 local crossed chickens. While crossing patterns showed limited impact, specific SNPs in exon 5 of the PRL gene were associated with BW, EW, and EL. The findings highlight PRL gene polymorphisms as valuable markers for improving reproductive traits in poultry breeding programs. Keywords: local crossed chickens, polymorphism, prolactin gene, reproductive traits, single-nucleotide polymorphisms.

Research Note: A low-density SNP genotyping panel for Chinese native chickens

The efficiency of molecular breeding largely depends on the cost of genotyping, which plays an important role in breeding and population genetic studies. Compared to pig, cattle, and sheep, poultry has a small size genome, and lower individual value. Developing a relatively low-density genotyping panel is needed to decrease the genotyping cost for poultries. In the present study, we developed a chicken 11 K single nucleotide polymorphism (SNP) genotyping panel for breeding and genetic analysis using genotyping by targeted sequencing (GBTS). The panel design was based on whole genome sequencing data from 7 local breeds and a commercial breed. In total 11,200 SNPs were included in the final chip. Population analyses of the eight breeds showed high SNP call rates and minor allele frequencies (MAF), enabling clear differentiation between populations. The families within population can also be identified. Additionally, the 11K panel was applied to a genomic prediction of Wenshang Barred chickens, the predictive ability and prediction accuracy between the WGS and chip dataset non-significantly differed. Therefore, the newly developed chicken low-density SNP is efficient, cost-effective, and well-suited for application in local Chinese chickens, which can accelerate chicken breeding improvements and enhance conservation efforts.

Free-caged rearing modes Regulate intestinal metabolism by influencing gut microbial homeostasis

Free-caged rearing modes, which prioritize animal welfare, are believed to enhance the quality of animal products. The impact of rearing modes on meat quality may play a key role in the superior quality of local chicken breeds. This study analyzed the cecal contents of free-range and caged black-bone chickens at different ages using metagenomic and metabolomic sequencing. We identified 32 metabolites and 367 microbial species significantly affected by the rearing mode. Linear discriminant analysis Effect Size (LefSe) highlighted five key microorganisms, Gemmiger formicilis, Bacteria unclassified, Bacteroides sp. ET225, Massilistercora timonensis, and Bacteroidales unclassified, that showed distinct abundance patterns across all age points. Among them, Bacteroides sp. ET225 and Massilistercora timonensis were positively associated with certain phospholipids and plant-derived metabolites, while negatively correlated with others like demissidine and acylcarnitine. Functional analysis revealed that rearing modes impact gut metabolites involved in gut metabolism as well as broader processes such as signal transduction, protein digestion, and autophagy. This study offers new insights into how rearing modes influence gut microbiota and metabolites, shedding light on the study of rearing mode-mediated muscle development and fat deposition.

Phenotypic characterization and principal component analyses of Bangkok chicken in Indonesia

ABSTRACT Bangkok chicken is a significant genetic resource in Indonesia, valued culturally and economically. However, limited reports on its phenotypic diversity risks genetic loss. This study aimed to assess phenotypic characterization of Bangkok chicken through qualitative and quantitative traits. Methods included qualitative classification, morphometric measurements, correlation, and principal component analysis (PCA). A T-test analyzed sex differences in body weight and morphometric traits. The research findings revealed that the male Bangkok chickens had 44.16% black-red (black dominant) feather colour and 73.20% yellow shank. Meanwhile, the females had 78% black feather colour and 34% black shank. The pea comb type was dominant in both sexes. The results indicated that the body weight and morphometric traits of male Bangkok were higher than those of females. In the total population, the PC1 accounted for 56.92% of the total variance. Morphometric features, such as breast girth and shank length were strongly correlated with body weight, highlighting their potential as reliable traits for selection and breeding Bangkok chickens. In conclusion, the study identified key phenotypic characteristics, which were body weight, breast girth, and shank length. These traits are strongly correlated and can serve as reliable criteria for selecting and improving Bangkok chicken breeds. Highlight The variation of qualitative traits of Bangkok chickens, consisting of feather colour, shank colour, and comb type, were widely varied across the population. Sexual dimorphism (male and female) affected all the parameters in quantitative traits, and the PCA identified breast girth and shank length as the key potential criteria for selecting Bangkok chicken.

Genome-wide analysis of Collo Nudo Italiana and Millefiori Piemontese local chicken breeds: genetic variability and structure analysis in the context of Italian chicken biodiversity

This study aimed to assess the genetic diversity and population structure of two Italian local chicken breeds, Millefiori Piemontese (PMP) and Collo Nudo Italiana (PCI), using the 600K Affymetrix SNP chip array, and to contextualise these breeds in the national biodiversity landscape based on 23 Italian local chicken breeds previously characterised. Minor allele frequency (MAF), expected heterozygosity (He), and observed heterozygosity (Ho) of PCI were 0.311 ± 0.170, 0.484 ± 0.107, and 0.469 ± 0.128, respectively. The inbreeding coefficient (FHOM) was −0.001 ± 0.066 and the inbreeding coefficient calculated on runs of homozygosity (ROH) values (FROH) was 0.003 ± 0.004. The PMP had MAF, He, and Ho of 0.245 ± 0.201, 0.383 ± 0.112, and 0.428 ± 0.149, respectively, and exhibited higher FHOM (0.149 ± 0.405) and FROH (0.016 ± 0.009) than PCI. The multi-dimensional scaling plot and neighbour-joining tree depicted clear genetic clustering for both the PCI and PMP breeds. The ROH analysis identified key genomic regions with significant gene annotations. In particular, four ROH islands in GGA4, GGA5, and GGA8 of PCI, and three ROH islands in GGA3 of PMP were detected. For PCI, ROH regions contained genes related to immune response and thermoregulation, such as S1PR1 and PLA2G4A. For PMP, ROH regions included genes involved in muscle development and immune response, such as RRM2, KLF11, and CPSF3. This research provided insights into the genetic diversity and adaptive traits of PCI and PMP breeds, contributing to widen the understanding of Italian local chicken genetic resources.

Meat-Producing Ability of Two Autochthonous Chicken Breeds Under Traditional and Semi-Intensive Conditions

The old Hungarian poultry breeds are the hidden reserves of the Carpathian Basin’s agriculture. The aim of this study was to examine the slaughter weight, carcass merit, and certain meat properties of two of them: the Partridge-colored Hungarian Chicken (PC) and the White Transylvanian Naked-neck Chicken (TN) under semi-intensive and traditional fattening conditions. Test slaughtering of chickens was conducted at 12th and 18th weeks of age. The eviscerated body weight (and the weight of cuts) of the PC (1140 g) and the cockerels of both breeds (1148 g) was larger than that of TN (878 g) and pullets (870 g). The farming system did not influence the carcass composition. At the same time, the pullets were characterized with larger values (p &lt; 0.001) in regards to, for example, the breast–whole leg (0.81:1), breast fillet–thigh fillet (1.29:1), breast fillet–breast bone proportion (2.40:1) in comparison to the cockerels (0.7:1, 1.10:1 and 2.17:1, respectively). Examinations of meat quality revealed that the pH-value of the thigh (5.73 vs. 5.83) and breast meat (6.21 vs. 6.43) of the PC was significantly lower. However, the lightness (L*) of breast fillet was higher (55.2) than that in the TN (49.9). In addition, the yellowness (b*) value of the breast meat and breast skin was significantly higher in the PC, but the redness (a*) of the breast skin was higher in the TN. Results showed that the farming system affects these values, too. Accordingly, the yellowness (b*) of breast meat, breast skin, thigh meat, and thigh skin was significantly higher in the traditional group. The PC showed more satisfactory results in poultry production today. However, the reddish meat of the TN should be emphasized, which is excellent and appropriate in traditional agriculture. It is argued that the indigenous chicken breeds should be supported for the chicken meat trade regardless of their competitiveness.