Search Results (95)

Phytate, an antinutritional molecule in poultry feed, can be degraded by applying phytase, but its use in low- and middle-income countries is often limited due to importation instead of local production. Here, inexpensive raw materials were used to optimize the production of a thermostable phytase from an indigenous strain of Bacillus subtilis SP11 that was isolated from a broiler farm in Dhaka. SP11 was identified using 16s rDNA and the fermentation of phytase was optimized using a Plackett–Burman design and response surface methodology, revealing that three substrates, including the raw material mustard meal (2.21% w/v), caused a maximum phytase production of 436 U/L at 37 °C and 120 rpm for 72 h, resulting in a 3.7-fold increase compared to unoptimized media. The crude enzyme showed thermostability up to 80 °C (may withstand the feed pelleting process) with an optimum pH of 6 (near pH of poultry small-intestine), while retaining 96% activity at 41 °C (the body temperature of the chicken). In vitro dephytinization demonstrated its applicability, releasing 978 µg of inorganic phosphate per g of wheat bran per hour. This phytase has the potential to reduce the burden of phytase importation in Bangladesh by making local production and application possible, contributing to sustainable poultry nutrition. Full article

The focus on selecting broilers for rapid growth rates and enhanced breast muscle yield has resulted in a decline in meat quality. The differences in carcass characteristics and meat quality between Hubbard white broilers (HWs, a commercial breed) and Xueshan chickens (XSs, an indigenous breed) at market age were analyzed to determine the potential mechanisms responsible for these differences. The results show that HWs exhibited significantly better carcass performance than XSs, including the larger weight of the carcass, the breast muscle, and the thigh muscle (p < 0.01). In addition, based on HE staining analysis, HWs’ breast muscles had a considerably larger average myofiber area and diameter than those of XSs (p < 0.01). Furthermore, the physical characteristics of the meat revealed that XSs had higher redness and yellowness and also higher lightness. HW meat had a higher pH and thermal loss, but a lower shear force and drip loss than XS meat (p < 0.01). The content of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) was, remarkably, lower in the breast muscles of HWs than of XSs (p < 0.01). In contrast, HWs had a larger concentration of monounsaturated fatty acids (MUFAs) than XSs (p < 0.01). Finally, the breast muscles of XSs had lower levels of mRNA expression for genes linked to lipid metabolism, such as fatty acid binding protein 4 (Fabp4) and peroxisome proliferator-activated receptor alpha (Pparα), and had higher levels of the phosphofructokinase muscle type (Pfkm) compared to HWs (p < 0.01). These results indicate that a lower carcass yield was observed in XSs compared with HWs, but that XSs showed better performance in terms of meat quality than HW. Full article

The Luhua chicken is an outstanding local breed in China that has been placed under conservation due to the impact of specialized breeding and the widespread adoption of commercial varieties. As such, this study analyzed reproductive traits across three consecutive generations and utilized whole-genome resequencing data from 60 Luhua chickens to assess conservation efficacy through genetic diversity, run of homozygosity (ROH) distribution, kinship, and population structure so as to better conserve the breed. The results show that, across generations, the body weight at first egg increased, the age at first egg was delayed, and the egg weight at first laying increased. No significant variations were found in the body weight at 300 d or the total egg number. The key genetic parameters of the polymorphism information content (PIC), expected heterozygosity (HE), observed heterozygosity (HO), and mean identical-by-state (IBS) distance were 0.234, 0.351, 0.277, and 0.782, respectively. The majority of ROHs ranged from 0.5 to 1 Mb, and the inbreeding coefficient based on ROHs was calculated at 0.021. The findings reveal that these traits remained unchanged across the three generations. Our research suggests that optimizing the mating plan of Luhua chickens is essential to minimize inbreeding risk. Furthermore, the methodology applied in this study provides a valuable reference for the conservation monitoring of other indigenous chicken breeds. Full article

The production of fermented sausages from poultry meat using traditional technologies and natural maturation conditions is a major challenge. The aim of this study was to identify indigenous microbiota with antilisterial activity from an innovative, additive-free, traditionally fermented chicken sausage. Isolates (n = 88) of lactic acid bacteria (LAB) were collected during maturation and subjected to MALDI-TOF mass spectrometry identification. The capacity to combat Listeria was screened against five strains using the agar well diffusion method in 63 selected LAB isolates. MALDI-TOF mass spectrometry identified four different LAB genera, namely Enterococcus, Lactococcus, Leuconostoc and Lactobacillus, the proportions of which differed significantly during the production phases (p < 0.001). Enterococcus faecalis was the most prevalent LAB species in the initial sausage dough. The presence of lactococci (Lactococcus lactis) and enterococci was detected during the 14- and 30-day ripening period and was gradually displaced by leuconostocs and lactobacilli. Lactobacilli appeared to be abundant during the central and late maturation phases, and consisted of only two species—Latilactobacillus sakei and Latilactobacillus curvatus. In total, 38 LAB isolates (60%) showed antilisterial activity toward at least one Listeria indicator strain. The proportions of antilisterial LAB differed significantly during sausage maturation. Inhibitory activity against all indicator Listeria was detected in the neutralized cell-free supernatants of five strains of Enterococcus faecalis, two L. sakei strains and one Leuconostoc mesenteroides strain. The antilisterial activity observed in the indigenous LAB revealed the possible role of L. sakei as a bioprotective culture, as well as the role of Ln. mesenteroides and E. faecalis as bacteriocin producers, for practical applications. Full article

The Lueyang black-bone chicken represents a distinct indigenous avian breed native to China and it is a slow-growing broiler breed. The gut, whose primary function is to digest food and absorb nutrients, is also home to a large and diverse microbial community. The intestinal morphology, intestinal metabolites, and gut microbiota are critical determinants of nutrient utilization efficiency and immune health in poultry. This study investigates the impact of two distinct rearing modalities—cage-raised (CR) and cage-free (CF)—on the intestinal morphology, intestinal metabolites, and gut microbiota of the duodenum and cecum in Lueyang black-bone chickens. Additionally, we have integrated metabolomics and microbiome analyses. Morphological assessments revealed that, in comparison to the CR group, the CF group exhibited a significant increase in duodenal villi height (VH) and crypt depth (CD) (p < 0.01). Furthermore, there was a notable increase in the number of intestinal inflammatory cells within the CF group. Non-targeted metabolomics indicated an upregulation of omega-3 series polyunsaturated fatty acids and bile acid metabolites in the CR group. Conversely, the CF group demonstrated significantly elevated levels of lysophosphatidylcholine (LPC) and phosphatidylcholine (PE) in the intestine. Microbiome analysis revealed that in the duodenum, beneficial bacteria (e.g., Lactobacillus) were the dominant genera in the CF group, while the Bacteroides predominate in the CR group. Correlation analyses indicated a positive association between LPC levels and the presence of eight bacterial genera, including Ureaplasma. The omega-3 series polyunsaturated fatty acids were positively correlated with three bacterial genera, such as Flavobacterium. Notably, bile acid metabolites exhibited a significant positive correlation with Rikenellaceae_RC9_gut_group. In conclusion, this study provides novel insights into how rearing methods influence intestinal morphology, intestinal metabolites, and gut microbiota, offering a new perspective for the scientific management of poultry with the premise of ensuring animal health and welfare. Full article

Chengkou mountain chicken, a Chinese indigenous breed, exhibits unique flavor characteristics. However, the genetic basis of its flavor precursor substances remains unexplored. We performed a genome-wide association study (GWAS) using low-coverage whole-genome sequencing (lcWGS) and genotype imputation to explore genetic markers linked to flavor precursors (nucleotides, amino acids, etc.) in Chengkou mountain chicken breast muscle. We identified 44 SNPs potentially or significantly associated with flavor precursor traits and localized 18 genes. Functional analysis revealed eight important candidate genes, including ZBTB20, RFX4, MAMLD1, SYN3, ABTB3, PRPF39, LRFN5, and DGCR14, which may play key roles in influencing flavor precursor substances. Moreover, two SNPs residing in the haplotype block (53,448,483 bp to 53,450,834 bp) on chromosome 1 were significantly associated with a di-unsaturated acyl chain (C20:2) residue and mapped to the ABTB3 gene. This study analyzes the composition of flavor precursor substances in the pectoralis major muscle of Chengkou mountain chicken. Moreover, the SNPs, haplotypes, and candidate genes identified in this study can be used to improve the accuracy of the marker-assisted selection of traits related to flavor precursor substances in the breast muscle of chicken. In addition, the candidate genes that are significantly associated with these traits will potentially lay the foundation for future genetic selection aimed at improving the flavor traits of chicken meat. Full article

Eggs are good sources of animal proteins. Methods for creating designer eggs are attractive to scientists and producers of the eggs, in order to fulfill customers’ demands. We review and summarize the current understanding of how genetic and environmental factors influence chicken egg components, specifically, amino acid contents of yolk and albumen. Genetically diverse breeds of chicken enable us to obtain a wide variety of egg amino acids. Moreover, the use of fermented feed and different rearing systems (barn and deep litter) has impacts on egg amino acids, which may be mediated through changes in the intestinal environment, including the microbiota. To overcome the future food crisis, the combinations of breeds, feeds, and rearing systems will be important for producing designer eggs. In the future, not only long-term selected layer strains will be required, but also many kinds of indigenous chicken breeds, which have already adapted to each local environment in the world, should be investigated under the continental levels of climate environment using different fermented feed materials. To better understand the interplay between genetic and environmental factors, we will offer valuable insights for both egg producers and consumers, potentially guiding future efforts to optimize egg amino acid contents in chickens. Full article

The objective of this study was to estimate the genetic parameters of the egg-laying traits of hens after long-term selection. Four lines were derived from Taiwan indigenous chickens conserved in situ by the National Livestock Biodiversity Program. A total of 9834 hens’ laying records from 18 non-overlapping generations classified as seven generational stages from 2006 to 2023 was used. The traits evaluated included body weight at 16 weeks of age, age at the first egg (Sday), body weight change between Sday and 40 weeks of age (Gain40), mean egg weight at 40 weeks of age (EW40), and egg number up to 40 weeks of age (EN40). A four-trait animal model via the REML procedure was used to estimate the variance/covariance components for each generational stage within each line. The ranges of the heritability estimates for Sday, Gain40, EW40, and EN40 were 0.09–0.61, 0.03–0.70, 0.32–0.83, and 0.00–0.65, respectively. Within the lines’ generational stages, most of the heritability estimates of Gain40 and EW40 were higher than those of Sday and EN40. Also, less fluctuation was found in the heritability estimates of Gain40 and EW40 among the generational stages within the lines. Favorable negative genetic and phenotypic correlations between Sday and EN40 were observed at the last generational stage, which could be beneficial for future breeding programs to improve egg production. Full article

This study examined the effects of dietary supplementation with grape seed proanthocyanidins (GSPs) on the growth performance, serum biochemistry, jejunal antioxidant capacity, and jejunal microbiota and metabolites in Chinese indigenous Kangle chicken. In this experiment, 120 female Kangle chickens aged 30 days old were randomly allocated into three treatment groups: a control group (CON) fed a standard diet and two experimental groups fed diets supplemented with 200 mg/kg (LGSP) or 400 mg/kg (HGSP) of GSPs. The experiment consisted of a 7-day adaptation period followed by a 30-day feeding trial. The results demonstrated that GSP supplementation did not significantly improve their average daily gain or feed efficiency. However, the HGSP group showed significant improvements in their liver and jejunal indices, a reduced jejunal crypt depth, and increased villus-height-to-crypt-depth ratios compared to these values in the CON group. Furthermore, the HGSP group also exhibited elevated concentrations of cholesterol in their serum. Additionally, the oxidative stress levels were probably reduced in the jejuna of the HGSP group, as evidenced by reduced malondialdehyde (MDA) contents. Although jejunal microbial diversity remained unchanged, the metabolomic analysis identified significant upregulation of jejunal metabolites, particularly those associated with free radical scavenging, protein nutrition, and bile acid metabolism, which would be beneficial for maintaining intestinal health. These findings indicate that supplementing their diet with 400 mg/kg of GSPs could improve the health of Kangle chickens, underscoring their potential as a functional feed additive in the production of indigenous Chinese chickens. Full article

Interest in indigenous and dual-purpose chicken breeds for sustainable poultry farming is growing. Additionally, incorporating local feed resources into their diets may enhance the nutritional value of their products while reducing environmental impact. This study investigated the ability of Echium oil (EO), rich in stearidonic acid (SDA, 18:4n-3) compared to linseed oil (LO) and high in alpha-linolenic acid (ALA, 18:3n-3), to increase long-chain n-3 polyunsaturated fatty acids (LC-PUFAs) in breast meat. Sixty Canarian cockerels were fed for six weeks with diets supplemented with 1.5% soybean oil (SO), 1.5% LO, or 2% EO. Final body weight and carcass traits showed no significant differences among groups (p > 0.05). However, EO-fed birds exhibited slightly higher breast meat lightness (L*) than LO-fed ones (p < 0.05). Total lipid content and lipid class composition remained unchanged (p > 0.05). Both LO and EO increased eicosapentaenoic acid (EPA, 20:5n-3) compared to SO, with EO further enhancing SDA, 20:3n-3, 20:4n-3, docosapentaenoic acid (DPA, 22:5n-3), and docosahexaenoic acid (DHA, 22:6n-3), resulting in meat with a healthier thrombogenic index (TI). Importantly, EO inclusion up to 2% did not negatively impact meat sensory qualities. These findings suggest that EO outperforms LO in enriching poultry meat with beneficial n-3 LC-PUFAs and holds great potential for poultry production. Full article

Avian leukosis (AL), a major vertically transmitted infectious disease, poses a significant challenge to the conservation and industrial development of indigenous chicken breeds in China. In this study, Chengkou mountain chickens were used as a model to systematically identify genetic markers associated with resistance to avian leukosis virus subgroup J (ALV-J) through a genome-wide association study (GWAS). Genomic DNA was extracted from 500 hens at 300 days of age, and cloacal swabs, plasma, and egg white samples were collected to assess the ALV-J infection status. A total of 325 ALV-positive (ALV+) and 175 ALV-negative (ALV−) individuals were identified. Based on 10× whole-genome resequencing and stringent quality control, 12,644,463 high-quality SNPs were obtained. GWAS revealed a significant enrichment of SNPs on chromosome 6 (Chr6), from which 218 SNPs significantly associated with ALV-J resistance and 49 candidate genes were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that many of these genes, including PTPN13, TTF2, TIAL1, DLG2, FBXL7, CDH5, and CDH11, are involved in tumorigenesis and immunosuppression through the JAK/STAT signaling pathway and cell adhesion molecule pathways. Additionally, candidate genes, such as ANKH, SLC4A7, and SLC5A1, were found to potentially regulate ALV-J infection by modulating membrane transport and inflammatory responses. This study is the first to identify ALV-J resistance-associated genetic markers in Chengkou mountain chickens, revealing key genes related to immune regulation, membrane function, and tumor development. The findings provide a foundational molecular basis for disease-resistant breeding in poultry. Full article

Heat-stress resilience is vital for poultry in tropical/subtropical regions where high temperatures impair productivity. Ake chickens, as the only naked-neck chicken breed in China, exhibit robust resistance to heat stress, but this breed lacks clarity in its genetic origins. This study utilized the next-generation sequencing data from 22 chicken breeds to conduct phylogenetic and population analyses. Gene flow analysis revealed a gene migration event from Iranian naked-neck chickens and Indian local breeds to Ake chickens, and population separation estimates suggested that the naked-neck gene was introduced to China around 500–600 years ago. NJ-tree, PCA, and population structure analyses showed that Ake chickens cluster with Yunnan native breeds, which diverged only 100–200 years ago. A selective sweep in the candidate region on chromosome 3 (97.0–97.37 Mb) showed elevated genetic differentiation (F_ST) and reduced nucleotide diversity (π) compared to the genome-wide average, indicating rapid fixation of the trait under natural/artificial selection. Demographic reconstruction indicated that the current effective size of Ake chickens is stable at 2000–3000 individuals. These findings deepen our understanding of Ake chicken evolution and provide valuable insights for conservation and the development of heat-stress-resistant poultry breeds. Full article

The gut microbiota is pivotal to chickens’ overall health, influencing digestion, nutrient absorption, and immune function. Dietary compounds significantly impact gut microbiota composition. House crickets (Acheta domesticus) have emerged as an alternative protein source for animal feed, rich in proteins and beneficial fatty acids. This study compared the gut microbiota in the cecum and ileum of Thai indigenous chicken breeds (Betong Chicken, white feather with black bone chicken, and black feather with black bone chicken) fed with or without house crickets. Using Oxford Nanopore Technology of 16S rDNA, this study found a similar relative abundance of gut bacteria across groups, with dominant bacteria including Firmicute, Bacteroidetes, Proteobacteria, and Actinobacteria. LEfSe analysis identified differential abundance of beneficial bacteria, such as Ruminococcaceae, Rikenella, and Deferribacteres, in the cecum of the black feather with black bone chicken after cricket feeding. Additionally, Lactobacillaceae exhibited differential abundance in the ileum of this breed post-cricket diet. Consequently, this study provides new data into the gut microbiota of Thai indigenous chickens. It suggests that house cricket diets did not significantly alter microbiota diversity but may enhance beneficial bacteria in certain breeds. Full article

Background/Objectives: The Changshun green-shell laying hen with a strong broodiness is a Chinese indigenous chicken breed. Little is known about the mechanisms responsible for the ovary development of Changshun green-shell laying hens from the egg-laying period (LP) to the incubation period (BP). Methods: A total of six hens were selected from LP (n = three) and BP (n = three) at 28 weeks old. The RNA sequencing (RNA-seq) of ovaries from hens in LP and BP groups was performed to identify candidate genes and pathways associated with broodiness. Results: We identified 1650 differently expressed genes (DEGs), including 429 up-regulated and 1221 down-regulated DEGs, in chicken ovaries between LP and BP groups. Gene ontology term (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these DEGs were mainly involved in the pathways related to follicle development in chicken ovaries, including focal adhesion, the MAPK signaling pathway, and the FoxO signaling pathway, and vascular smooth muscle contraction, ECM–receptor interaction, and the GnRH signaling pathway were down-regulated in incubating ovaries. Eight candidate genes (EGFR, VEGFRKDRL, FLT1, KDR, PDGFRA, TEK, KIT and FGFR3) related to angiogenesis, folliculogenesis, steroidogenesis and oogenesis in ovaries were suggested to play important roles in the ovarian development of Changshun hens during the transition from LP to BP. Conclusions: This study identified a range of genes and several pathways that may be involved in regulating the broodiness of Changshun green-shell laying hens. These data are helpful to further enrich our understanding of the mechanism of incubation behaviour in chickens. Full article

Background/Objectives: Eggshell quality is a critical factor influencing consumer preference and the economic benefits of poultry enterprises, and the uterus is the key site for eggshell synthesis. Yaoshan chicken (YS), an indigenous chicken breed in China, is renowned for its flavorful meat and high-quality eggs. However, its egg production is lower compared to specialized strains. Therefore, the GYR crossbreed was developed by three-line hybridization for YS chicken, which can produce green-shelled eggs with better eggshell thickness and strength than YS chicken (p < 0.01). To explore the molecular mechanisms underlying the differences in eggshell quality between GYR and YS chickens, we conducted an integrated transcriptomic and metabolomic analysis. Methods: Twelve uterus samples (six from GYR and six from YS chickens) were collected during the period of eggshell calcification at 260 days of age. RNA sequencing (RNA-seq) and liquid chromatography–mass spectrometry (LC-MS/MS) were performed to identify differentially expressed genes (DEGs) and differential metabolites (DMs), respectively. Results: A total of 877 DEGs were identified in the GYR group, including 196 upregulated and 681 downregulated genes (|log₂ (fold change)| > 1, p-value < 0.05). Additionally, 79 DMs were detected, comprising 50 upregulated and 29 downregulated metabolites (|log₂ (fold change)| > 1, VIP > 1). Notably, the key DEGs (SLCO1B3, SLCO1B1, PTGR1, LGR6, MELTF, CRISP2, GVINP1, and OVSTL), important DMs (prostaglandin-related DMs and biliverdin) and signaling pathways (calcium signaling, neuroactive ligand–receptor interaction, arachidonic acid metabolism, bile secretion, and primary bile acid biosynthesis) were major regulators of the eggshell quality. Furthermore, an integrated transcriptomic and metabolomic analysis revealed two significant gene–metabolite pairs associated with eggshell quality: PTGDS–prostaglandin E2 and PTGS1–prostaglandin E2. Conclusions: This study provides a theoretical foundation for the improved eggshell quality of Yaoshan chicken. Full article