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Simple Summary: The genetic polymorphisms in the ovocalyxin-32 gene were studied in the present work with regard to egg quality traits in indigenous chicken populations. In the same investigation, based on exons 1 and 6, the frequencies of G/T and A/G SNPs regarding the Hardy–Weinberg equilibrium (HWE) and their role in egg quality were determined. The T allele of the G/T SNP in exon 1 was associated with thinner shells and lower shell strength, while the A/G SNP in exon 1 resulted in eternal eggs with thicker shells in AG and AA genotypes. Regarding this, the A/G SNP in exon 6 was able to enhance shell and yolk quality in AG genotypes. These SNPs could be considered candidate genetic markers for marker-assisted selection (MAS) focusing on egg quality improvement, which has additive and dominance genetic effects on phenotypic variation. This study sought to evaluate the genetic variations of the ovocalyxin-32 gene and its association with egg quality traits in indigenous chicken populations, focusing on exons 1 and 6. Genotype frequencies of SNPs (G/T and A/G) within these exons were assessed for their conformity to the Hardy–Weinberg equilibrium (HWE) across several strains. While most strains exhibited close adherence to HWE expectations, some like light-brown and gray strains indicated substantial discrepancies, particularly for the TT genotype, which points towards the possible effects of genetic drift as well as selection pressures. This study also analyzed the influence of such SNPs on egg quality parameters. A thinner eggshell, reduced shell weight, and decreased breaking strength were associated with the G/T SNP in exon 1, suggesting a likely negative effect on egg quality in T allele carriers. Conversely, the AG genotype displayed better performance in shell thickness, weight and egg weight in the A/G SNP in exon 1, whilst yolk height was best improved by the AA genotype compared to breaking strength. For instance, in exon 6, the A/G SNP enhanced the shell and yolk quality among AG genotypes, while the CC genotype resulted in better eggshell characteristics with enlarged yolks because the C/T SNP was linked. Nonetheless, there were no significant deviations from the HWE despite these associations, which suggested that most breeds had a stable genetic background. Further, considering SNPs' additive and dominant effects in this research, it was indicated that additive effects account for phenotypic expressions given by the G/T SNP located at exon 1. In contrast, significant additive and dominant effects were observed under the A/G SNP situated at the exon. Generally, it therefore could be concluded from this study that specific SNPs within the ovocalyxin-32 gene may act as good markers for marker-assisted selection (MAS) that can improve desired characteristics—such as those of egg quality—in indigenous chicken breeds. This study demonstrated that both additive and dominance effects must be taken into account when performing genetic analyses, thereby emphasizing the complexity of phenotypic variation caused by genetic mechanisms in native chicken races. [ABSTRACT FROM AUTHOR]

Native chickens in Ethiopia are characterized in a fragmented manner for their performance characteristics and genotypes. This review aimed to explore the production and reproduction performance characteristics as well as the morphometric and morphological diversity of Ethiopian native chickens. The investigation was performed on four production performance characteristics, including average egg per clutch, average clutch/hen/year, average egg set/hen, and average egg/hen/year, as well as six reproductive performance characteristics, including age at first laying, age of male chickens at first bred, age at which female chickens are first bred, the reproductive life span of males and females, and fertility percentage in various parts of Ethiopia. Some economically practical morphometric characteristics of native chickens, such as shank length, chest circumference, comb length, body weight, body length, keel length, wattle length, neck length, back length, and morphological diversity, were also summarized. Regarding performance characteristics, there were some variations in eggs’ average production performance per clutch (13.56-15.4 eggs) and clutch/hen/year (3.0-4.29) in Ethiopia. The average reproduction performance characteristics of Ethiopian native chickens for age at first laying (6.90-7.13 months), age of male chickens at first bred (5.87-6.15 months), female at first bred (5.20-5.93 months), the reproductive life span of males (3.79 years) and hens (3.56 years), and chicks hatched from set eggs revealed variation across Ethiopia. In various locations of Ethiopia, the average trait values reported for Ethiopian native chickens under the farmer’s management differed in terms of morphometric and morphological features. The variation observed in performance characteristics, as well as morphometrics and morphological characteristics for Ethiopian native chicken ecotype population, can help the native breed classification, unique trait conservation, and breed improvement intervention programs. [ABSTRACT FROM AUTHOR]

The present study was conducted to assess the comparative laying performances of three native chicken genotypes under intensive management. Egg production was recorded up to 280 days. For Kadaknath (K), a total of 500 pedigree hatched day old chicks were identified individually by wing band. In seventh generation, 26.19%, 10.89% and 18.18% birds of Non-descript Deshi (ND), Hilly (HI) and Naked Neck (NN) had laid egg ranged 80-89%. Chick weight was not affected (p>0.05) by genotype. Fertility of ND, HI and NN was 88.96%, 87.03% and 86.67%, respectively. Significantly (p<0.001) the highest hatchability (90.85%) was found in ND compared to HI (89.25%) and NN (83.94%). The highest egg production number of ND, HI and NN were 79.08, 69.33 and 74.86, respectively. In this study, the average HDEP% of ND, HI and NN were found to be 56.48, 49.52 and 53.47, respectively. Body weight at first lay is 1111.0g and at 8th week is 685.4g. FCR at 0-8 week is 3.0. Significantly (p<0.05) the lowest glucose content was found in K chicken (4.34mMol/L) compared to HI (7.34mMol/L)), NN (5.88mMol/L) and ND (5.76mMol/L). Iron content of blood was nonsignificantly highest in K chicken compared to other three native chickens. Haemoglobin content of blood was non-significantly highest in HI chicken. ND was superior for egg production, fertility and hatchability traits. No extra ordinary result was found in case of Kadaknath chicken. [ABSTRACT FROM AUTHOR]

Commercial chickens that were selected for both meat and egg production were domesticated from the descendants of red junglefowl (Gallus gallus) species that have been widely spreading in Asia, including Indonesia. There were an estimated 32 strains of local chicken in Indonesia with high morphological diversity. The one of contributors to the diversity of Indonesian local chicken is called "Bangkok" chicken. As a reference to the name of the chicken, it is a suspected descendent of Thai game fowl (Gallus gallus domesticus Linnaeus, 1758) which was introduced in Thailand region many years ago. The objective of this study was to explore the existence of this chicken related to the genetic relationship with the Indonesian local chicken. This study was conducted in East Java Province which covered sample areas Banyuwangi, Pasuruan, and Madiun Regencies. The materials were "Bangkok" chicken offspring with a total of 450 birds. The observed variables consisted of qualitative and quantitative morphological characters, both male and female of adult chickens (1 yr to 1.5 yr old). The highest frequency of the comb shape was Single comb (36.9 %) and the lowest was Rose shape (11.8 %). While the highest frequency of shank colour was blackish-yellow (45.6 %) and the white color (3.6 %) was the lowest. The closest genetic distance base on morphometric diversity was between Pasuruan and Banyuwangi chickens (96.04). It was suspected due to the distance area between Pasuruan and Banyuwangi closer than Madiun and Banyuwangi, while Madiun and Pasuruan was the farthest genetic distance (682.03). Hence, the breeding program of Bangkok chicken based on the genetic distance needs further consideration to prevent inbreeding from occurring. Otherwise, the closest distance should be called for to upgrade the purity of the Bangkok chicken ancestor. [ABSTRACT FROM AUTHOR]

Objective: The genomic response and the role of genetic variants in hypoxia condition are always interesting issues about adaption pathways at genomic level. Herein, we carried out a comparative genomic study between highland and lowland native chickens, in order to identify the adaptive variants in hypoxia condition. We generated more than 20 million genetic variants in highland and lowland chickens. Finally, 3877 SNVs including the mtDNA ones, were discovered as novel adaptive genetic variants. The generated data set can provide new insight about mechanism of adaptation to hypoxia at genomic level. Data description: To investigate the role of genetic variants in adaptation to hypoxia, 10 whole-genome sequencing data sets associated to highland and lowland native chickens were provided. DNA was extracted by salting-out protocol. Paired-end 125 bp short reads were sequenced by Illumina Hiseq 2000. Variants calling of highland and lowland native chickens were performed by fix ploidy algorithm in CLC Genomic Workbench. Total genetic variants of highland chickens were compared to lowland chickens in order to identify the differential genetic variants (DGVs) between highland and lowland chickens. In this way, 3877 novel SNVs (VCF format) including the mtDNA ones, were deposited at EBI database (https://identifiers.org/ena.embl:ERZ491574) for the first time. [ABSTRACT FROM AUTHOR]

The study was carried out to investigate the carcass and meat quality traits and nutritional profile of the meat of the Kadaknath, a unique native chicken breed in comparison with commercial broilers. The yield of the carcass, breast and giblets of the Kadaknath was lesser (p < 0.01), while that of the legs, wings, back, and neck was higher (p < 0.01) than broilers. The meat of the Kadaknath was significantly (p < 0.0001) darker (42.44, 50.92) and more yellow (6.23, 8.99) than broilers. The decline in pH of the meat was lower (p < 0.001) in the Kadaknath compared to broilers. Kadaknath meat had more protein and less fat, moisture and ash content than broilers (p < 0.01). Furthermore, it was richer (p < 0.01) in 11 amino acids, including those which are known to impart a sweet and umami taste, than the meat of broilers (3 amino acids). Both genotypes were almost similar in meeting the daily requirements of indispensable amino acids of adult human. The study concluded that the Kadaknath differed in carcass and meat quality characteristics from the broilers, and the nutritional quality of Kadaknath meat in terms of high protein and less fat and higher content of amino acids (tasty type) was better in Kadaknath meat as compared to broiler meat. [ABSTRACT FROM AUTHOR]

Bioconversion product of shrimp waste with BLS microbes (Bacillus licheniformis, Lactobacillus spp. and Saccharomyces cerevisiae) holds digestive proteases with a great potential to be used as prebiotics for native chicken. In the present work, the ratio of liquid extract bioconversion product and binders formulated both 4:1 (T1); 5:1 (T2), and 6:1 (T3) to entrap prebiotics enzymes from BLS microbes have been characterized. The trials were needed to verify contained in prebiotics from encapsulated liquid extract on quality of feed supplement. The overall results indicated that binders formulated T2 (5:1) capsules of prebioticsBLS extract were better vehicles to deliver shrimp enzymes in native chickens. The implication of metabolizable energy and digestibility at Indonesian local chicken showed that T2 binders formulated improve protein digestibility (80%) and metabolizable energy (3033 kcal/kg) of local chicken. Feeding trial prebiotic BLS used at four levels (0, 0.5, 1, 1.5, or 2%) at basal feed (protein 28.22%), with one treatment of standard feed (protein 32.18%). Supplementing diets with prebiotic BLS, especially at 1.5%, has a variety of growth-promoting effects. The results demonstrate that the observed benefits of prebiotic BLS on low protein diets can be achieved. [ABSTRACT FROM AUTHOR]

The Newcastle disease virus (NDV) is the deadliest chicken pathogen in low-input village poultry, and selecting for NDV resistance has been recommended as a sustainable strategy in backyard poultry production systems. However, selecting for disease resistance needs precision data from either a big population sample size or on many generations with good pedigree records for effective prediction of heritability (h2) and breeding values of the foundation stock. Such conditions are almost impossible to meet in low-input backyard production systems. This study aimed at proposing a realistic method for estimating the heritability of the immune response to vaccination and survival of NDV infection in village poultry production to inform a breeding strategy for ND resistance in Cameroon. A 1 and 3% selection intensity of cocks and hens for higher antibody (ab) response (ABR) to vaccination followed by progeny selection of chickens who survived an experimental NDV infection was conducted from an initial population of 1,702 chickens. The selection induced an increase of 1012.47units/ml (p <0.01) of the NDV antibody of the progeny as well as an effective survival rate (ESR) increase of 11.75%. Three methods were used to estimate the heritability ( h 2 ) of NDV antibody response to vaccination. h 2 was low irrespective of the method with estimates of 0.2227, 0.2442, and 0.2839 for the breeder's equation method, the graphical method, and the full-sib/half-sib nested design, respectively. The mortality rate of infected chickens was high (86%). The antibody response to selection was not influenced by sex and genetic type even though the opposite was observed (p <0.05) for the ESR to NDV infection with naked neck chickens recording an ESR of 14% against 2.25% for the normal feather type. A very low heritability (0.0891) was observed for the survival against NDV infection. We confirm the evidence of disease resistance and the effect of selection for antibody response to vaccination on the improvement of the survival against NDV disease. Although the full sib/half sib nested design is more appropriate in case of availability of pedigree information, the direct methods are still useful in case of unavailability of full pedigree information. It is recommended that gene expression analysis should be prioritized for disease-resistance assessment and selection of native breeds of poultry. [ABSTRACT FROM AUTHOR]

Eighty (80) native chickens kept by small-hold farmers in mountain barangays of Ayungon, Negros Oriental, Philippines were sampled to determine phenotypic characteristics using the protocol of FAO (2012). Results showed that native chickens found in the area had high physical uniformity in terms of plumage pattern, comb type, skin and earlobe color. Comparison of morphological traits between males and females showed significant dimorphism in body weight (P<0.01) while no differences were observed in terms of age, body length, chest circumference, wingspan, and shank length. Further, body weight was found to be significantly correlated with body length (r=0.44), the circumference of the chest (r=0.59) and shank length (r=0.24). All other morphometric traits were not significantly correlated. The results of this study could provide valuable inputs to the purification of a potentially novel genetic group of native chickens from Negros Oriental. [ABSTRACT FROM AUTHOR]

• Estimation of genetic parameters provides valuable insights into the growth and egg production traits of Korean native chicken pure lines. • High heritability values in growth traits, particularly in KNC line Y, indicate the potential for genetic improvement through performance testing. • Low heritability estimates in egg production traits highlight the importance of implementing effective management strategies to enhance productivity. • Positive correlations among growth traits suggest shared genes, indicating that genetic improvement in one trait can positively impact other correlated growth traits. • The moderate accuracy of estimated breeding values (EBVs) underscores their effectiveness as indicators of true breeding value, supporting future genetic improvement programs in Korean native chicken pure lines. Korean native chickens (KNC) have a rich history and are highly regarded by Korean consumers owing their distinct flavors and textures. However, their slow growth and limited egg production pose challenges compared with commercial chicken breeds. To address these limitations and enhance economically important traits, such as growth and egg production, understanding their genetic foundations is necessary. We studied five KNC lines (F, H, S, W, and Y) and assessed them for weight at 8, 10, and 12 weeks of age and the total number of eggs laid. The analysis incorporated pedigree data from 50773 chickens from Hanhyup Breeder chickens. Line F showed a mean inbreeding coefficient of 0.0017, whereas the other lines exhibited lower mean values ranging from 0.0005 to 0.0028, indicating that the inbreeding levels were within an acceptable range and considered safe from extinction. The average relatedness was 0.46–1.88 % among the studied lines. Heritability estimates for growth traits in line F were relatively high (ranging from 0.32 to 0.35), indicating a significant contribution of additive genetic variance and suggesting potential for genetic improvement through performance testing. However, the heritability of the egg production trait was low (0.07–0.16), indicating a greater role of non-genetic factors in explaining phenotypic variation. Management strategies should focus on improving these characteristics. Genetic correlations revealed strong positive associations between selected growth traits (up to 0.98), whereas all growth traits were negatively correlated with the total number of eggs laid. This suggests shared genetic influences on growth traits and highlights the potential for improving multiple correlated traits by enhancing the genetic performance of one trait. We also assessed the accuracy of estimated breeding values (EBVs), which ranged from 0.55 to 0.69 and 0.42 to 0.58 for growth traits and egg production trait, respectively. These moderately accurate estimates indicated that EBVs can effectively indicate the true breeding value of an animal. To improve accuracy, it is essential to maintain reliable phenotypic and pedigree records, as well as increase the number of animals in the flock. Therefore, this study provides insights into the genetic parameters and breeding value accuracy of growth and egg production traits in KNC, facilitating future genetic improvement programs for these economically important traits. [ABSTRACT FROM AUTHOR]

The objective of this study was to search for single nucleotide polymorphism (SNP)-type polymorphisms in the dopamine D1 receptor in West Azerbaijani native chicken and look for their association with egg production and body weight traits of chickens by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). For this purpose 180 blood samples were taken from native chickens in a poultry breeding station in West Azerbaijan, Iran. DNA was extracted from blood samples using the salting-out procedure. Specific primers were designed for PCR amplification of the 283 base segment of the dopamine D1 receptor gene. In order to demonstration of gene polymorphism, Single-stranded conformation polymorphism followed by sequencing was performed. Four samples from each banding pattern were sent for sequencing. The polymorphism was found in the D1 receptor gene (G123A). We detected three genotypes in DRD1 gene. The frequencies of three genotypes were 0.42 (AA), 0.49 (AG), and 0.09 (GG), respectively. The analysis of variance was performed using of SAS software. The Result shows that there was a significant relationship between genotypes of dopamine D1 receptor gene with egg production traits. This finding indicates that the dopamine D1 receptor gene was polymorphic and could be a candidate locus or linked to a major gene that influences reproductive traits in chickens. [ABSTRACT FROM AUTHOR]

Background: Modern breeding in the poultry industry mainly aims to produce high-performance poultry lines and breeds in two main directions of productivity, meat and eggs. To understand more about the productive potential of lowly selected Chinese native chicken populations, we selected 14 representative SNP markers strongly associated with growth traits or carcass traits and 14 SNP markers strongly associated with egg laying traits through previous reports. By using the MassArray technology, we detected the genotype frequency distributions of these 28 SNP markers in seven populations including four lowly selected as well as one moderately selected Sichuan native chicken populations, one commercial broiler line and one commercial layer line. Results: Based on the genotype frequency distributions of these 28 SNP markers in 5 native chicken populations and 2 commercial lines, the results suggested that these Chinese indigenous chicken populations have a relatively close relationship with the commercial broiler line but a marked distinction from the commercial layer line. Two native chicken breeds, Shimian Caoke Chicken and Daheng Broilers, share similar genetic structure with the broiler line. Conclusions: Our observations may help us to better select and breed superior domestic chickens and provide new clues for further study of breeding programs in local chicken populations. [ABSTRACT FROM AUTHOR]

In the present study, we quantified myoglobin (Mb) gene expression in two different indigenous chicken breeds, namely Ghagus and Aseel to discern tissue specific expression pattern in different age groups. Quantitative real-time PCR assay was developed for measurement of the Mb mRNA expression in different tissues in chickens of different age groups (day old and day 28). Overall, the Mb mRNA level displayed a significant difference among all the tissues investigated in the study. Results exhibited that, bursa and heart tissues relatively had the highest expression of Mb related to the other tissues (P<0.05). Further, in gizzard and bursa, a significant difference was found in the expression between both the breeds studied. It is concluded that the expression of Mb gene varied significantly among different tissues and between age groups in chicken. [ABSTRACT FROM AUTHOR]

The research aims to define the breeding objective traits of Boholano strain of native chicken using participatory approach to be incorporated for its purification. A total of 45 households were interviewed. The questionnaire was designed to collect data covering general information on village poultry production such as socio-management characteristics, production objectives, population structure, breed choice and trait preferences, market preferences of specific traits, and farmers' selection practices. The participatory farmers' discussions were designed to involve stakeholders in defining the breeding objective traits and deriving their relative importance in the production environment based on the different functions of chickens and traits identified in the interviews. The results showed that production of eggs for consumption is the principal function of chickens in most towns followed by the use as source of income and meat for home consumption. Weight is the primary factor that dictates market price but farmers rated growth and number of eggs as the production traits that they would like to be improved. Therefore, the breeding objective should be to develop dual-purpose Boholano strain of native chicken considering the traits of number of eggs and live weight and possessing the distinct plumage color and comb type. [ABSTRACT FROM AUTHOR]

In the present study, the polymorphism of myostatin gene (MSTN) in native chickens of Western Azerbaijan Rearing and Breeding Institute was investigated. The blood samples were collected from eighty two randomly selected hens. Genomic DNA was extracted from blood samples and a fragment of myostatin including 599 bp in promoter and exon 1 was amplified using PCR method. Breeding values for body weight and carcass traits were predicted by univariate animal mixed model analysis, using WOMBAT software. The effects of different SSCP genotypes on breeding and phenotypic values of the studied traits were evaluated by general linear model analysis. Three different single strand conformational polymorphism (SSCP) genotypes as AA, AB and AC were identified, with frequencies of 0.244, 0.549 and 0.207, respectively. Shannon and Nei gene diversity indices and number of effective alleles in the studied population were 0.88, 0.53 and 2.2, respectively, which indicated a high diversity of the studied population. Moreover, the studied population was not in Hardy-Weinberg equilibrium. The effect of the SSCP genotypes on breeding and phenotypic values was significant only in the case of breeding value for body weight at 12 weeks of age, whereas, the AC genotype individuals, significantly (P<0.05) had the lowest breeding value for body weight at 12 weeks of age. Based on the results obtained, it could be concluded that the studied fragment of myostatin gene is polymorphic in native chickens of Azerbaijan and could be used for marker assisted selection. [ABSTRACT FROM AUTHOR]