Poultry is a source of meat that is in great demand in the world. The quality of meat is an imperative point for shoppers. To explore the genes controlling meat quality characteristics, the growth and meat quality traits and muscle transcriptome of two indigenous Yunnan chicken breeds, Wuding chickens (WDs) and Daweishan mini chickens (MCs), were compared with Cobb broilers (CBs). The growth and meat quality characteristics of these two indigenous breeds were found to differ from CB. In particular, the crude fat (CF), inosine monophosphate content, amino acid (AA), and total fatty acid (TFA) content of WDs were significantly higher than those of CBs and MCs. In addition, it was found that MC pectoralis had 420 differentially expressed genes (DEGs) relative to CBs, and WDs had 217 DEGs relative to CBs. Among them, 105 DEGs were shared. The results of 10 selected genes were also confirmed by qPCR. The differentially expressed genes were six enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathways including lysosomes, phagosomes, PPAR signaling pathways, cell adhesion molecules, cytokine–cytokine receptor interaction, and phagosome sphingolipid metabolism. Interestingly, four genes (LPL, GK, SCD, and FABP7) in the PPAR signal pathway related to fatty acid (FA) metabolism were elevated in WD muscles, which may account for higher CF, inosine monophosphate content, and AA and FA contents, key factors affecting meat quality. This work laid the foundation for improving the meat quality of Yunnan indigenous chickens, especially WD. In future molecular breeding, the genes in this study can be used as molecular screening markers and applied to the molecular breeding of chicken quality characteristics.

The eggshell quality traits in avian species, including Yunnong chickens (YN), are crucial for commercial and breeding purposes. The use of advanced biotechnologies, such as gene sequencing, has become increasingly common for identifying genetic markers and comparing specific traits in livestock. However, genetic markers related to eggshell traits in YN chickens remain unexplored. This study aimed to compare eggshell quality traits and identify genetic markers in YN chickens versus commercial Jingfen chickens (JF). A total of 400 chicks (200 per breed) were reared for 300 days under controlled conditions. At the end, 60 eggs from each breed were analyzed using scanning electron microscopy to examine eggshell cross-sections and mammillary layer structure. Tissue samples from kidneys and eggshell glands were collected from six hens per breed for RT-qPCR analysis to study gene expression profiles. Results showed that YN chickens had significantly higher eggshell strength, thickness, mammillary density, and effective layer thickness than JF chickens (p < 0.01). Despite this, YN chickens had a thinner mammillary layer. RT-qPCR analysis confirmed five candidate genes related to eggshells (LSS, NSDHL, MSMO1, SQLE, and FDFT1) that play an important role in this process. Pathway analysis revealed significant enrichment in several biological processes, including steroid biosynthesis, glycerolipid metabolism, purine metabolism, and thiamine metabolism. Based on these results, the YN chickens have strong eggshells with better thickness, mammillary density, and effective layer thickness. In addition, genomic and pathways analysis suggest a complex interaction of metabolic, immune, and cellular processes potentially influencing eggshell quality traits in poultry.

Sexual maturation provides economically important traits in poultry production. Research on the initiation mechanism of sexual maturity is of great significance for breeding high-yield laying hens. However, the underlying mechanisms are not fully clear. Here, one hundred and fifty Chahua No. 2 laying hens (the CH2 group, which has precocious puberty) and one hundred and fifty Wu Liang Shan black-bone laying hens (the WLS group, a late-maturing chicken breed) with similar weights and ages were randomly selected. ELISA was used to determine the secretion levels of luteinizing hormone (LH), estradiol (E2), and progesterone (P4) in 150-day-old serum and small yellow follicle (SYF) tissues. A histology examination, immunohistochemistry, and quantitative real-time PCR (qPCR) were used to explore the molecular mechanism of how some genes related to oxidative stress affect sexual maturation. The results showed that the secretion levels of LH, E2, and P4 in the CH2 group serum and SYF were higher than those in the WLS group. The results of the real-time PCR of all genes showed that the expression levels of cytochrome P450 family 11 subfamily A member 1, steroidogenic acute regulatory protein, follicle-stimulating hormone receptor, and cytochrome P450 family 19 subfamily A member 1 in the CH2 group were significantly higher than those in the WLS groups (p < 0.001). Untargeted metabolomics combined with multivariate statistical analysis was used to identify biomarkers of SYF tissues in the CH2 and WLS groups. A trajectory analysis of the principal component analysis (PCA) results showed that the samples within the group were clustered and that the samples were dispersed between the CH2 and the WLS groups, indicating that the results of the measured data were reliable and could be used for further research. Further analysis showed that a total of 319 metabolites in small yellow follicles of the CH2 and WLS groups were identified, among which 54 downregulated differential metabolites were identified. These 54 metabolites were found as potential CH2 biomarkers compared with WLS at 150 days, and the different expressions of L-arginine, L-prolinamide, (R)-4-hydroxymandelate, glutathione, and homovanillic acid were more significant. Twenty metabolic pathways were found when significantly differential metabolites were queried in the KEGG database. According to the impact values of the metabolic pathways, eighteen differential metabolites belonged to the mTOR signaling pathway, glutathione metabolism, ABC transporters, the cell ferroptosis pathway, and D-arginine and D-ornithine metabolism. Interestingly, we identified that the cell ferroptosis pathway played an important role in chicken follicle selection for the first time. The histology and immunohistochemistry of SYF showed that the number of granulosa cells increased in the CH2 groups and the expression levels of glutathione peroxidase 4, tumor protein p53, ribosomal protein S6 kinase, and sterol regulatory element binding protein 1 in the granulosa cell layer were upregulated in the CH2 group at the time of sexual maturation. Furthermore, we also speculated that the antioxidant system may play an indispensable role in regulating sexual maturity in chickens. Overall, our findings suggest differentially expressed metabolites and metabolic pathways between CH2 and WLS chickens, providing new insights into the initiation mechanism of sexual maturation.

Egg production is a vital biological and economic trait for poultry breeding. The ‘hypothalamic–pituitary–ovarian (HPO) axis’ determines the egg production, which affects the layer hens industry income. At the organism level, the HPO axis is influenced by the factors related to metabolic and nutritional status, environment, and genetics, whereas at the cellular and molecular levels, the HPO axis is influenced by the factors related to endocrine and metabolic regulation, cytokines, key genes, signaling pathways, post-transcriptional processing, and epigenetic modifications. MiRNAs and lncRNAs play a critical role in follicle selection and development, atresia, and ovulation in layer hens; in particular, miRNA is known to affect the development and atresia of follicles by regulating apoptosis and autophagy of granulosa cells. The current review elaborates on the regulation of the HPO axis and its role in the laying performance of hens at the organism, cellular, and molecular levels. In addition, this review provides an overview of the interactive network regulation mechanism of the HPO axis in layer hens, as well as comprehensive knowledge for successfully utilizing their genetic resources.

【Objective】The Y-strain chicken was obtained by crossing the Chahua 2 E-strain rooster with Digao D-strain hen， and the N-strain chicken was obtained by crossing the Tengchong Snow chicken rooster with Digao D-strain hen. It was aimed to evaluate the growth performance of the two hybrid progeny， explore the growth and development law of the most dominant hybrid progeny， and determine the optimal growth curve model.【Method】The Y-strain chickens and N-strain chickens born on the same day were selected as the research objects， After that， the body weight indexes of 0-29 weeks of age were measured， and the growth and development were recorded. At 60， 90 and 120 days of age， 30 males and females were randomly selected for body weight and body size measurement， and the differences and correlations of the two breeds were compared to determine the most dominant hybrid offspring; The three nonlinear growth models of Logistic， Gompertz and von Bertalanffy were used to fit the body weight of different hybrid offspring under different genders， and the best growth curve model was obtained.【Result】The results showed that the body weight of Y-strain roosters was significantly better than that of N-strain roosters， and Y-strain hens were slightly better than N-strain hens in the weight growth curve of 0-29 weeks old. During the measurement of body weight and body size， two breeds all showed that roosters were significantly larger than hens （P＜0.01）， and Y-strain chickens were significantly better than N-strain chickens. The most hybrid Y-line chicken was used for the growth curve fitting analysis， and it was found that the von Bertalanffy model was closer to the measured value， which was the best growth curve model for the Y-line chicken. Moreover， the correlation analysis of body weight and body size showed that there was a high correlation between the body weight and shin circumference of Y-strain chickens， and it could be used as a reference standard for Y-strain chicken breeding in the future. 【Conclusion】The improvement effect of Y-strain chickens obtained from the cross of the E strain of Chahua Chicken No.2 and the D strain of Digao Chicken is better than that N-strain chickens obtained from the cross of Tengchong Snow Chicken and the D strain of Digao Chicken. And the von Bertalanffy model was the best growth of Y-strain chicken.

几十年来,我国蛋鸡产业都在稳定发展,标准化规模化的发展趋势一直处于畜牧业前列水平.尤其是自主创新品种,近几年成为畜牧业中的领军者.再加上政府出台的各项扶持政策,使得蛋鸡产业处于我国乃至世界领先地位,但是免疫力与生产性能两者无法同时达到最佳水平,是导致蛋鸡产业停滞不前的根本原因之一.目前为止,关于禽类免疫方面的系统介绍较为匮乏.因此,全面总结禽类免疫特征,了解禽类最新免疫进展,试图从中找到免疫力与生产性能同时达到最佳水平的平衡点,持续高效发展蛋鸡产业,具有十分重要的实际经济价值.本文概述了蛋鸡免疫、免疫性指标、免疫抑制性疾病的作用机理及影响因素,简单介绍了自身免疫调控,详细阐述了营养性免疫调控机制与策略,旨在为未来蛋鸡行业更加高效、绿色经济、稳步发展提供新的参考.

Matrix metalloproteinases are a group of proteases involved in the regulation of ovarian follicular development and ovulation. Among the different MMPs, MMP13 is known to play an important role in reproduction. Therefore, this study aimed to screen the molecular genetic markers of the MMP13 gene that affect the egg-laying performance of Chahua chickens. Polymerase chain reaction (PCR) and sequencing were performed in the 5′ regulation region of the MMP13 gene to detect loci significantly related to the egg-laying performance of Chahua chickens. A double fluorescence reporting system, quantitative reverse transcription PCR (RT-qPCR), and Western blotting were used to study whether gene expression was regulated by identified sites, providing a theoretical basis to improve egg production in Chahua chickens. The results revealed six single nucleotide polymorphisms (SNPs; A-1887T, T-1889C, A-1890T, T-2252C, T-2329C, and C-2360A) in the promoter region of the MMP13 gene. Further analysis revealed that hens with T-1890-C-1889-T-1887/T-1890-C-1889-T-1887 (mutant type, MT) had an earlier age at first egg (AFE) than hens with A-1890-T-1889-A-1887/A-1890-T-1889-A-1887 (wild type, WT; p < 0.05). RT-qPCR showed that the relative expression level of the MMP13 gene in the ovarian tissues of individuals with the mutation was higher than that of individuals with the wild gene (p < 0.05). Western blot results confirmed higher levels of the MMP13 protein in MT ovaries compared to those in WT ovaries. Thus, this study suggests that mutation sites on the MMP13 promoter may affect gene expression. In conclusion, the MMP13 gene in Chahua chickens may be significant for egg-laying performance, and the polymorphism in its promoter region could be used as a molecular marker to improve egg-laying performance.

Toll样受体(TLRs)是一类胚系基因编码的Ⅰ型跨膜糖蛋白模式识别受体,其通过识别病原体,激活天然免疫,诱导产生多种细胞因子,在免疫稳态和抗病过程中发挥重要作用.TLRs在功能上参与识别自身和非自身抗原,架起了先天免疫和适应性免疫的桥梁.TLRs可激活相关信号分子,同时也可引起胞内炎性介质的转录和表达,募集促炎因子和共刺激分子,促进炎症反应,进而激活非特异性和特异性免疫,共同清除抗原异物.本文综述了 TLRs的定义、结构及其在不同病原微生物感染时的免疫调控机制,为以后应用TLRs预防和诊断细菌性病原感染和病毒感染疾病奠定基础.

Tengchong snow, which has white feathers and black meat, is one of the most important black-bone chicken breeds and a genetic treasure of black food in China. Although the black meat traits are dominant, there are some chickens with white meat traits born in the process of folk selection and breeding. The purpose of this study was to compare the differences in skeletal muscle development between Tengchong snow black meat chickens (BS) and white meat chickens (WS), as well as whether excessive melanin deposition has an effect on skeletal muscle development. The BS and WS groups were selected to determine their muscle development difference at stages of 1, 7, 14, 21, and 42 days, using histological stain methods to analyze the development and composing type of breast and leg muscle fibers, as well as the count of melanin in BS muscle fibers. Finally, we were validated key candidate genes associated with muscle development and melanin synthesis. The results showed that BS breast muscle development was inhibited at 7, 14, and 21 days, while the leg muscle was inhibited at 7, 14, 21, and 42 days, compared to WS. Melanin deposition was present in a temporal migration pattern and was greater in the leg muscles than in the breast muscles, and it focused around blood vessels, as well as the epithelium, perimysium, endomysium, and connective tissue. Additionally, melanin produced an inhibitory effect similar to MSTN during skeletal muscle fiber development, and the inhibition was strongest at the stage of melanin entry between muscle fibers, but the precise mechanisms need to be confirmed. This study revealed that melanin has an inhibitory effect on the early development of skeletal muscle, which will provide new insights into the role of melanin in the black-boned chicken and theoretical references for the future conservation and utilization of black-boned chicken.

Chicken is the most widely consumed meat product worldwide and is a high-quality source of protein for humans. The skeletal muscle, which accounts for the majority of chicken products and contains the most valuable components, is tightly correlated to meat product yield and quality. In domestic chickens, skeletal muscle growth is regulated by a complex network of molecules that includes some non-coding RNAs (ncRNAs). As a regulator of muscle growth and development, ncRNAs play a significant function in the development of skeletal muscle in domestic chickens. Recent advances in sequencing technology have contributed to the identification and characterization of more ncRNAs (mainly microRNAs (miRNAs), long non-coding RNAs (LncRNAs), and circular RNAs (CircRNAs)) involved in the development of domestic chicken skeletal muscle, where they are widely involved in proliferation, differentiation, fusion, and apoptosis of myoblasts and satellite cells, and the specification of muscle fiber type. In this review, we summarize the ncRNAs involved in the skeletal muscle growth and development of domestic chickens and discuss the potential limitations and challenges. It will provide a theoretical foundation for future comprehensive studies on ncRNA participation in the regulation of skeletal muscle growth and development in domestic chickens.

禽法氏囊的结构发育与其免疫功能密切相关,二者直接关系到禽养殖业的健康发展.为了解法氏囊发育与免疫功能的研究近况,采用文献综述和归纳总结的方法,阐述现阶段法氏囊发育与免疫功能的研究新进展.结果表明:1)法氏囊发育始于原基发生,最新研究发现该过程与内外胚层均相关;影响造血干细胞向法氏囊定向迁移的具体因素尚未完全理清,但趋化因子起着重要作用,如CXCL12-CXCR4轴参与B淋巴细胞对法氏囊的定植;目前将法氏囊增龄性退化机制归咎于机体内激素水平的变化,主要为性固醇类激素、生长激素以及皮质固醇类激素,但哪种激素起主导作用则尚存争议.2)法氏囊对B淋巴细胞进行筛选的关键是B淋巴细胞前体表面免疫球蛋白的重排形式以及B淋巴细胞表面受体复合物与肠道抗原的结合情况;法氏囊分泌的囊素肽在促进B淋巴细胞增殖与分化中起重要作用,目前19种囊素肽已被鉴定;法氏囊的免疫功能易受到多种因素影响,目前常见的影响因素包括病原微生物及环境应激源,它们能以直接或间接的方式引起法氏囊结构的损伤和淋巴细胞的损耗从而引起机体的免疫抑制.针对研究现状,提出仍待解决的问题:法氏囊能与其他器官组织进行互作,但调控该过程的关键因子筛选与验证仍处于探索阶段.随着技术的发展与革新,将推动法氏囊免疫功能的更深入研究,也将为实践生产提供多维度的理论指导.

近年来,我国的水产品需求不断增大,养殖规模发展迅速并不断扩大,但在鱼类养殖过程中常常出现各种疾病制约水产业绿色健康和可持续发展.在食品安全与人口持续增长的双重压力下,传统的疫苗、抗生素等化学药品在养殖过程中长期使用引起的药物残留、抗药性、水体污染等问题,已经严重威胁到鱼类养殖行业的持续健康发展,且不符合现代健康养殖的需求.因此,发掘安全有效的药物替代品成为研究的热点.而植物多糖由于具有抗氧化、免疫等生物活性,可以用作提高鱼类生长性能、增强免疫力的有效刺激剂,在鱼类养殖中具有广阔的应用前景.综述了鱼类养殖过程中植物多糖对鱼类生长、抗菌抗病、免疫、抗氧化和血糖血脂等方面影响的研究进展,并对未来研究从3个方面进行了展望:即从细胞和分子层面研究植物多糖对鱼类免疫性能、抗菌抗病、抗氧化等影响的相关作用机制;研究植物多糖与其他物质联合使用的协同作用效果;利用植物多糖的抗氧化、提高免疫性能、降血糖血脂等优点,将植物多糖与其他食品原料进行复合,开发功能性食品等.

This study aimed to explore the underlying reasons for the differences in egg production in Chinese Chahua chickens. The Chahua chicken population was divided into two groups, namely a high-yielding group (H) and a low-yielding group (L). The egg-laying performance, ovarian morphology, histological characteristics, and serum hormone concentrations in the H and L groups were analysed. The results revealed that there were significant differences (P < 0.01) between the two groups for the age at the first egg and the number of eggs. The H group showed significantly more (P < 0.01) hierarchical follicles and small yellow follicles than the L group. While several secondary follicles and primary follicles were observed in the ovaries of the H group, only a few secondary follicles were observed in the ovaries of the L group. The serum concentrations of the follicle-stimulating hormone, the luteinising hormone, and oestradiol were significantly higher in the H group compared to that in the L group (P < 0.01). Next, we sequenced and analysed the ovarian expression profiles in the two groups using RNA-seq. The transcriptome sequencing revealed 875 differentially expressed genes (DEGs) between the H and L groups. Of the 875 DEGs, 624 were up-regulated, and 251 were down- regulated. The DEGs were mapped to 31 Gene Ontology (GO) terms and 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for the ovarian tissue. The KEGG pathway analysis mainly revealed the involvement of focal adhesion, cytokine-cytokine receptor interaction, and the TGF-beta signalling pathway, while the GO analysis mainly showed involvement of the hormonal activity, extracellular matrix, and extracellular region. Our results showed that understanding the differences in the gene expressions between the ovarian tissues of high- and low- yielding hens may provide a useful reference for improving the egg-laying performance in Chahua chickens.

骨骼肌是生物机体的重要组成部分,约占产肉动物机体的40％,与畜禽的运动、发育及产肉能力等重要性状密切相关.骨骼肌是由平行排列的肌原纤维组成的多核肌纤维,肌纤维的数量、类型以及转变方式直接反映了个体肌肉发育情况以及机体的生理状况,因而在选育工作中作为重要的经济性状而被关注.对肌纤维的深入研究将有助于加快今后的选育进程,促进对近年频发的畜禽肌源性疾病的溯源与研究,从而缓解肌源性疾病对畜禽养殖业造成的经济损失,满足消费者对优质肉产品的需求.近年来,对肌纤维的认识与研究均取得重大进展,包括依照肌纤维的结构与功能特性对骨骼肌的生物学功能进行预测与验证、肌纤维的类型与肉品质的关联分析以及模式动物的应用,挖掘出肌纤维发生发育以及再生修复过程中的重要调控分子,并对它们的功能进行注释.作者参照现有研究成果对肌纤维的结构与功能进行系统的描述,并从分子层面对肌纤维胚胎期的发生发育以及出生后的再生修复进行综述,以期为今后提高肉用动物的产肉性能及培育高品质产肉动物新品种或新品系的选育工作提供理论参考.