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Objective: Yellow Korean native chicken (KNC-Y) is one of the five pure Korean indigenous chicken breeds that were restored through a government project in 1992. KNC-Y is recognized for its superior egg production performance compared to other KNC lines. In this study, we performed runs of homozygosity (ROH) analysis to discover selection signatures associated with egg production traits in the KNC-Y population. Methods: A total of 675 DNA samples from KNC-Y were genotyped to generate single nucleotide polymorphism (SNP) data using custom 60K Affymetrix SNP chips. ROH analysis was performed using PLINK software, with predefined parameters set for the analysis. The threshold of ROH island was defined as the top 1% frequency of SNPs withing the ROH among the population. Results: In the KNC-Y population, a total of 29,958 runs of homozygosity (ROH) fragments were identified. The average total length of ROH was 120.84 Mb, with each ROH fragment having an average length of 2.71 Mb. The calculated ROH-based inbreeding coefficient (FROH) was 0.13. Furthermore, we revealed the presence of ROH islands on chromosomes 1, 2, 4, 5, 7, 8, and 11. Within the identified regions, a total of 111 genes were annotated, and among them were genes related to economic traits, including PRMT3, ANO5, HDAC4, LSS, PLA2G4A, and PTGS2. Most of the overlapping quantitative trait locus regions with ROH islands were found to be associated with production traits. Conclusion: This study conducted a comprehensive analysis of ROH in the KNC-Y population. Notably, among the findings, the PTGS2 gene is believed to play a crucial role in influencing the laying performance of KNC-Y. [ABSTRACT FROM AUTHOR]

The recent rediscovering of the Millefiori Piemontese breed, previously considered as extinct, has led to its genetic characterisation: establishing the basis for its recovery and preservation. This study describes the morpho-biometric traits and compares the genetic variability of the Millefiori Piemontese breed with that of other local chicken breeds using 26 microsatellite markers. A subset of 14 markers was used to compare the genetic variation of the Millefiori Piemontese breed with that of two other Piedmontese chicken breeds (Bionda Piemontese and Bianca di Saluzzo) as well as 17 Italian and 2 commercial hybrids, whose genetic variability has already been investigated. The present study confirmed the sexual dimorphism and assessed the genetic variability of the Millefiori Piemontese in terms of number of alleles/locus (Na = 4), the effective number of alleles (Nea = 3), observed (Ho = 0.56) and expected heterozygosity (He = 0.53), self-coancestry (IB = 0.65), potential extinction risk (ERI = 2), and its contribution to the Italian poultry biodiversity (GDT = −0.60). The results indicate that, despite its small population size (Ne = 56), the Millefiori Piemontese population exhibits significant genetic diversity, making it a valuable resource for breeding programs focused on preserving the breed and safeguarding its biodiversity. This study is the first to investigate the genetic variability of the Millefiori Piemontese breed and compare it with other local poultry breeds. The findings highlight the genetic uniqueness of the Millefiori breed and its significant contribution to the biodiversity of chickens in Piedmont and Italy, emphasising the importance of its conservation.

Simple Summary: The non-phytate phosphorous (NPP) requirements of laying hens vary significantly at different stages of growth and development due to their differing physiological characteristics. Non-linear models and factorial methods are often used to estimate the nutritional requirements of animals at different stages of growth. In this study, the NPP requirement of Chinese Jing Tint 6 layer chicks from hatch to d 42 was evaluated using both a non-linear model and factorial method. The non-linear models were fitted based on the criterion of growth performance, serum biochemical parameters, bone characteristics, and phosphorus utilization. The factorial methods were used to classify the requirements of the layer chicks into growth requirements and maintenance requirements. Based on the current results, it was recommended that dietary 0.367% and 0.439% NPP benefit from the best P utilization of 1–14 and 15–42 d birds, respectively. By predicting the nutritional needs of poultry at different stages as accurately as possible, the model can help formulate more scientific and reasonable feed formulation. We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn–soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1–14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15–42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1–14 and 15–42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1–14 and 15–42 d birds, respectively, to optimize P utilization without affecting performance. [ABSTRACT FROM AUTHOR]

We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn–soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1–14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15–42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1–14 and 15–42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1–14 and 15–42 d birds, respectively, to optimize P utilization without affecting performance.

1. Killing male one-day-old chicks, especially from layer lines, is banned in some European countries. Therefore, dual-purpose chickens, where each sex is used for meat and egg production, respectively, offer an alternative production solution. This study evaluated the British purebred breed Ixworth as a dual-purpose chicken for meat and egg production. 2. Ixworth chicks (n = 167) were hatched and reared mixed-sex in a floor housing system, with two groups receiving a commercial pullet diet (treatment 1) and two groups receiving a diet composed for males of layer lines (treatment 2). Individual chick performance data were recorded. Males were slaughtered at 12 weeks of age, and their growth rate and carcase variables were analysed. All hens were continuously reared on the pullet diet and kept in a free-range system from 20 weeks old for one laying period (52 weeks). In addition, group-based feed consumption and mortality were recorded. 3. Cockerels in treatment 1 and 2 showed significantly different [T(88) = −2.846, P = 0.003] growth rates (25.3 vs. 27.4 g/day) and average final weights (2166 g vs. 2344 g). The hens in treatment 1 (n = 41) laid an average of 193 eggs per hen housed (mean egg weight: 56.9 g), whereas those in treatment 2 (n = 35) laid 195 eggs per hen housed (mean egg weight: 56.5 g). Nest acceptance was >97.5% and feed consumption was up to 140 g/bird/day. 4. The results showed that the Ixworth may be a suitable breed for dual-purpose use and could be improved through selective breeding, offering potential for preservation of this local breed as well as general biodiversity in poultry farming. [ABSTRACT FROM AUTHOR]

Objective: Yellow Korean native chicken (KNC-Y) is one of the five pure Korean indigenous chicken breeds that were restored through a government project in 1992. KNC-Y is recognized for its superior egg production performance compared to other KNC lines. In this study, we performed runs of homozygosity (ROH) analysis to discover selection signatures associated with egg production traits in the KNC-Y population., Methods: A total of 675 DNA samples from KNC-Y were genotyped to generate single nucleotide polymorphism (SNP) data using custom 60K Affymetrix SNP chips. ROH analysis was performed using PLINK software, with predefined parameters set for the analysis. The threshold of ROH island was defined as the top 1% frequency of SNPs withing the ROH among the population., Results: In the KNC-Y population, a total of 29,958 runs of homozygosity (ROH) fragments were identified. The average total length of ROH was 120.84 Mb, with each ROH fragment having an average length of 2.71 Mb. The calculated ROH-based inbreeding coefficient (FROH) was 0.13. Furthermore, we revealed the presence of ROH islands on chromosomes 1, 2, 4, 5, 7, 8, and 11. Within the identified regions, a total of 111 genes were annotated, and among them were genes related to economic traits, including PRMT3, ANO5, HDAC4, LSS, PLA2G4A, and PTGS2. Most of the overlapping quantitative trait locus regions with ROH islands were found to be associated with production traits., Conclusion: This study conducted a comprehensive analysis of ROH in the KNC-Y population. Notably, among the findings, the PTGS2 gene is believed to play a crucial role in influencing the laying performance of KNC-Y.

The thymus-derived lymphocytes of jawed vertebrates have four T-cell receptor (TCR) chains that play a significant role in immunity. As chickens have commercial value, their immune systems require a great deal of attention. Local chicken breeds are an essential part of poultry genetic resources in China. Here, we used high-throughput sequencing to analyze the TCRα and TCRβ repertoires and their relative expression levels in the native chicken breeds Baier Buff, Longyou Partridge, Xiaoshan, and Xianju. We found that TCR Vα and TCR Vβ were expressed and included 17, 19, 17, and six segments of the Vα2, Vα3, Vβ1, and Vβ2 subgroups, respectively. V-J pairing was biased; Jα11 was utilized by nearly all Vα segments and was the most commonly used. Breed-specific V segments and V-J pairings were detected as well. The results of the principal coordinate analysis (PCoA) as well as the V-J pairing and CDR3 diversity analyses suggested that the four local chicken breeds did not significantly differ in terms of TCR diversity. Hence, they expressed not significant differentiation, and they are rich genetic resources for the development and utilization of immune-related poultry breeding. • Both Vα subgroups and Vβ subgroups are expressed in chicken. • Various TCR diversity with V segments, V-J pairing, and CDR3 diversity. • No significant differentiation of TCR diversity parameters among local chicken breeds. [ABSTRACT FROM AUTHOR]

Nowadays most of the Italian chickens’ breeds are replaced with commercial hybrids characterised by higher productive performance. However, the safeguard of biodiversity and consequently the genetic variability are a very important issue, and for this reason, it is fundamental to include local strains in preservation programs. In Italy, the poultry Genealogic Book has been recently constituted, and includes 22 chicken breeds. The diffusion of these strains is strictly linked to the territory of origin, in particular in the Central Italy, the Ancona and Livorno chicken breeds are the mainly widespread ones. The aim of this study was to determine the consistency and the characteristics of the farms involved in the farming of Ancona and Livorno chicken breeds in Central Italy. A survey to analyse the facilities, the human resources and the chicken population consistencies was conducted in the farms of Abruzzo, Lazio, Marche, Tuscany and Umbria regions. All the investigated farms can be identified as ‘hobby-farms’ being small scale ones and leading the breeding of Ancona and Livorno chickens as a secondary business. The survey also confirmed that the presence of the strains depends on the region: 100% of Marche farms bred Ancona whereas, in Tuscany the Livorno breed is the most common.Highlights A survey in centre Italy was carried out to determine the consistency of Ancona and Livorno chicken breeds; The Ancona and Livorno chickens breed were reared in small scale farms; The widespread of the breeds depend on the region: Ancona breed is most present in the Marche region while the Livorno is mainly bred in Tuscany.

Nowadays most of the Italian chickens' breeds are replaced with commercial hybrids characterised by higher productive performance. However, the safeguard of biodiversity and consequently the genetic variability are a very important issue, and for this reason, it is fundamental to include local strains in preservation programs. In Italy, the poultry Genealogic Book has been recently constituted, and includes 22 chicken breeds. The diffusion of these strains is strictly linked to the territory of origin, in particular in the Central Italy, the Ancona and Livorno chicken breeds are the mainly widespread ones. The aim of this study was to determine the consistency and the characteristics of the farms involved in the farming of Ancona and Livorno chicken breeds in Central Italy. A survey to analyse the facilities, the human resources and the chicken population consistencies was conducted in the farms of Abruzzo, Lazio, Marche, Tuscany and Umbria regions. All the investigated farms can be identified as 'hobby-farms' being small scale ones and leading the breeding of Ancona and Livorno chickens as a secondary business. The survey also confirmed that the presence of the strains depends on the region: 100% of Marche farms bred Ancona whereas, in Tuscany the Livorno breed is the most common. A survey in centre Italy was carried out to determine the consistency of Ancona and Livorno chicken breeds; The Ancona and Livorno chickens breed were reared in small scale farms; The widespread of the breeds depend on the region: Ancona breed is most present in the Marche region while the Livorno is mainly bred in Tuscany. [ABSTRACT FROM AUTHOR]

In Belgium, as generally in Europe, the dominant position of the high producing commercial strains specialized in meat or eggs production threats of extinction the local traditional breeds. In this work, a follow up of the changes in populations size, and the rates of inbreeding of the Belgian poultry breeds, has been carried out in 2005 and 2010. About forty breeds were concerned. The Belgian hen breeds being overwhelmingly under threat of extinction, because of the low number of individuals by breed. For each of these breeds, various criteria were considered, risk status, breeding male to breeding female ratio, effective population size, effective population size to actual size ratio and rate of inbreeding. [ABSTRACT FROM AUTHOR]

Abstract: Local chicken breeds are a vital reservoir of gene resources and their conservation has a technical role related to the future development of the productive system, as well as a social-cultural role. The aim of this study was to evaluate the effects of egg weight, egg storage period and egg weight loss on hatchability of fertile eggs in the Italian bantam breed Mericanel della Brianza. Fourteen females and eight males were kept in floor pens and divided in 8 families (1M:1 or 2F) during the reproductive season (March–June). Birds received a photoperiod of 14L:10D and were fed ad libitum. Egg production and egg weight were recorded daily. Eggs were divided in 4 weight groups: EW1=<33g, EW2=33–36g, EW3=36–39g and EW4=≥39g. Eggs were stored at 18°C and classified in 3 egg storage groups: ES1=0–4, ES2=5–9 and ES3=10–15 days. Egg weight loss was recorded and distributed in 5 different classes: EWL1=<10%, EWL2=10–15%, EWL3=16–20%, EWL4=21–25%, EWL5=>25%. Fertility, embryo mortality and hatchability were recorded. The mean values during the reproductive season were 82% fertility and 50% hatchability of fertile eggs. The best combination of fertility and hatchability values were recorded in EW2 and lower fertility was recorded in EW1 (P <0.05). Hatchability decreased under 50% after 10 day storage period before incubation and the best hatchability was recorded in EWL1. The present results contribute to the knowledge on reproductive parameters necessary to improve the reproductive efficiency of this Italian breed within a conservation plan. [Copyright &y& Elsevier]

The aim of this study was to compare the intra and inter genetic variability and population structure of 7 indigenous chicken breeds of the Veneto region, through a novel panel of 64 SNP, each located in an exonic region and mostly on different chromosomes. A total of 753 blood samples from 7 local chicken breeds (Ermellinata di Rovigo, Millefiori di Lonigo, Polverara, Pepòi, Robusta Lionata, Robusta Maculata, and Padovana) was collected and analyzed. Two strains of Polverara (Nera and Bianca) and Padovana (Dorata and Camosciata) were included in the study. The observed heterozygosity ranged from 0.124 (Pèpoi) to 0.244 (Ermellinata di Rovigo), and the expected heterozygosity varied from 0.132 (Millefiori di Lonigo) to 0.300 (Ermellinata di Rovigo). Global FIS results (0.114) indicated a low-medium inbreeding effect, with values ranging from 0.008 (Millefiori di Lonigo) to 0.223 (Ermellinata di Rovigo). Pairwise FST values (0.167) for all populations ranged from 0.020 (Polverara Nera and Polverara Bianca) to 0.193 (Robusta Lionata and Polverara Nera), indicating that the studied breeds were genetically highly differentiated. The software STRUCTURE was used to detect the presence of population substructures, and the most probable number of clusters (K) of the 10 chicken populations was at K = 8. The affiliation was successful in all Veneto chicken breeds. The present SNP marker results, compared with previous data obtained using microsatellites, provided a reliable estimate of genetic diversity within and between the studied breeds, and demonstrated the utility of the proposed panel as a rapid, efficient, and cost-effective tool for periodical monitoring of the genetic variability among poultry populations. In addition, the present SNP panel could represent a resource for a systematic approach with relevant impact on breeding program decisions and could turn out to be a reliable tool for genetic traceability of indigenous chicken meat. Adoption of a periodical monitoring system of genetic diversity is a fundamental tool in conservation actions and should increase the value of typical and niche products., (© 2017 Poultry Science Association Inc.)