Feather pecking is a common and serious act of destruction in the production of laying hens, which can cause damage to the feathers and skin of the pecked chickens, and even results in mortality. Feather pecking not only does negative impact on the health and well-being of laying hens, but also further affects the benefit of farming layers, therefore received extensive attention from the layer industry and research. This review aims to synthesize the existing research results to explore the external influencing factors and genetic regulatory mechanisms of feather pecking behavior of laying hens, so as to promote the in-depth understanding of feather pecking behavior of laying hens, and put forward future research directions. This provides the basis for developing sustainable solutions, improving the welfare of laying hens, and increasing production efficiency.

The development of genomic selection has left a profound mark on beef cattle breeding. In China, the multitude of beef cattle breeds with small population sizes has led to a slow pace in genetic breeding efforts. Most studies indicate that purebred beef cattle populations with large reference groups gain little benefit from multi-breed evaluations, while breeds with smaller reference groups can benefit from such evaluations without adversely affecting the assessment of purebred performance. In the field of beef cattle genetic breeding research, the use of genomic information provides an opportunity to enhance the genetic improvement of beef cattle, thereby determining the value of multi-breed reference groups such as hybrid breeds for beef cattle genetic breeding. Multi-breed genomic assessment, as a beneficial tool for increasing the genetic gain of populations, can evaluate the genomes of beef cattle populations using multi-breed models. This review focuses on the perspective of genomic selection in beef cattle, highlighting the use of genomic selection across multi-breed beef cattle breeds, discussing the mechanisms by which genomic selection is applied in beef cattle, with the aim of providing new insights for research into genomic selection in multi-breed beef cattle and exploring the potential applications of genomic selection.

This study aimed to investigate the genetic structure of the Beijing black pigs based on runs of homozygosity (ROH) and selection signals|iHS|analysis and to identify candidate genes related to economic traits. The subjects of this study were Beijing black pigs, with an average age of 210 days. After quality control and imputation of the illumina Porcine 50K chip data from 729 Beijing black pigs, the ROH and|iHS|were analyzed. In this study, the threshold for ROH islands was set at the SNPs that constituted the top 1% of ROHs, and regions exceeding this threshold were termed ROH islands. All SNPs in the top 1% of standardized |iHS| values were retained, and the areas extending 200 kb upstream and downstream of these SNPs were considered as the strong selection regions obtained by the iHS. The overlapping areas between the strong selection regions of the selection signals and the ROH islands were defined as the candidate regions for this study. In this study, 724 individuals and 45 585 SNPs were retained, and a total of 10 ROH islands containing 449 SNPs were identified by ROH analysis, and the results of|iHS|analysis showed that a total of 376 strongly selected SNPs were retained after the top 1% SNPs with the highest score were retained. In the end, a total of 18 genes in the overlapping regions of the 5 strongly selected regions of |iHS| and ROH islands were annotated, including some genes known to affect pork quality and growth and development. This study analyzed the distribution of ROH in the Beijing black pigs and revealed potential selected SNPs and candidate genes combined with selection signals. The results provide an important reference for further exploring the population characteristics and genetic mechanisms of economic traits of Beijing black pigs.

The aim of this study was to develop a rapid identification method of pork quality images based on computer vision technology, and to lay a technical foundation for solving the defects of traditional pork quality determination methods and constructing a rapid pork quality determination system. In this study, canny edge detection algorithm, normalization, gamma correction, adaptive histogram equalization and thresholding were used for image processing to simulate a three-dimensional model of porcine dorsal longest muscle using two-dimensional information, and an image-based computer vision method for determining porcine intramuscular fat content was developed. An image-processing-based eye muscle area recognition method was developed using manual depiction and computer vision contour search techniques. The underlying algorithmic programs of each method were implemented using Open CV and C++, and a system for the determination of porcine intramuscular fat content and eye muscle area was developed and tested using 250 test pigs of different breeds. The test results showed that the intramuscular fat content detection module could quickly realize the extraction and prediction of intramuscular fat graphical information, with an average detection time of no more than 2 minutes for a single sample, an accuracy of up to 0.54, and a discrete coefficient of 0.062, which was highly stable. The eye muscle area and backfat thickness detection module can quickly determine eye muscle area and backfat thickness by combining manual and computerized methods. The assay method and software system developed in this study enable rapid detection of intramuscular fat content, backfat thickness and eye muscle area in pigs.

The aim of this study was to investigate the effect of vitrification on gene expression in porcine parthenogenetic activation (PA) blastocysts. In this study, porcine PA blastocysts were divided into fresh, vitrification group Ⅰ and vitrification group Ⅱ according to the experimental treatments, and then 3 well-morphologised blastocysts were selected from each group and analysed by transcriptome sequencing using Smart-seq2 single-cell full-length transcriptome sequencing technology. As a result, compared with the fresh group, a total of 772 differential expression genes (DEGs) were identified in the vitrification group Ⅰ. GO and KEGG enrichment analysis results showed that these DEGs were related to cellular lipid metabolic process, cell glucose homeostasis, MAPK signaling pathway, PI3K-Akt signaling pathway, etc. Compared with the fresh group, a total of 1 613 DEGs were identified in the vitrification group Ⅱ, which mainly related to gluconeogenesis, metabolic pathways, biosynthesis of amino acids, etc. Compared with the vitrification group Ⅰ, 822 DEGs were identified in the vitrification group Ⅱ, which mainly involved in pyruvate metabolic process, N-Glycan biosynthesis, cellular senescence, etc. In summary, this study revealed the effects of vitrification on the expression of genes related to lipid metabolism, energy metabolism, MAPK signalling pathway and other related genes in porcine PA blastocysts based on Smart-seq2 single-cell full-length transcriptome sequencing technology.

This study aimed to investigate the potential function of FKBP5 in ovine ovarian granulosa cells (GCs). GCs were isolated from the ovaries of twenty approximately 2-year-old sexually mature Altay sheep obtained from the Hualing slaughterhouse in Urumqi. The experiment was divided into 4 groups: GC (blank control), GC+NC (transfected with siRNA-NC), GC+siFKBP5 (transfected with siRNA-FKBP5), and GC+siFKBP5+LH (treated with luteinizing hormone and transfected with siRNA-FKBP5). Immunofluorescence was used to detect the localization of FKBP5 protein in GCs. Its effects on cell proliferation and apoptosis were examined using EdU, Tunel assays, and Western Blot analysis. Its impacts on the AKT and ERK signaling pathways were assessed by Western blot, while the levels of E2 and P4 were measured by ELISA. FKBP5 was found to be expressed in the cytoplasm of GCs. Its expression increased with the increasing concentration of LH, reaching a peak at 5 IU·mL^-1 LH after 4 h of treatment (P < 0.001). Knockdown of FKBP5 significantly inhibited cell proliferation, as evidenced by a reduction in PCNA protein expression (P < 0.001). It also significantly promoted cell apoptosis, with an increase in BAX expression and a decrease in Bcl-2 expression (P < 0.001). Additionally, FKBP5 knockdown markedly suppressed the activation of the AKT and ERK signaling pathways and the secretion of E2 and P4 (P < 0.001). LH treatment partially mitigated the effects of FKBP5 knockdown on GCs (P < 0.05). The results indicate that FKBP5 influences the proliferation and apoptosis of ovine GCs, as well as the activation of the AKT and ERK signaling pathways and the secretion of E2 and P4. Its function is modulated by LH. These findings provide a theoretical basis for further research on the role of FKBP5 in ovine follicular development.

The objective of this study was to investigate the accuracy and additivity of digestible energy (DE), metabolizable energy (ME) and net energy (NE) predicted from simulated digestion method in feed for growing pig, which will provide a reference for quickly determining effective energy in feed. A single factorial completely randomized design was adopted for the determination of enzymatic hydrolysate gross energy (EHGE) of 12 energy feed ingredients, 9 protein feed ingredients and 17 diets formulated by the above 21 feed ingredients.Each treatment contained 5 replicates with 1 digestive tube per replicate. The DE, ME and NE were predicted by EHGE combined with crude protein (CP) and acid detergent fiber (ADF). The difference and correlation between the predicted effective energy (DE, ME and NE) values and the in vivo values estimated by gross energy (GE) multiplied by energy utilization coefficients in the GB/T 939235—2020 of 17 feed ingredients with the same name as this study were calculated to verify the accuracy of effective energy predicted from simulated digestion method. The difference between the weighted values of effective energy calculated by individual value of feed ingredients and the values predicted by the mathematical model of effective energy from EHGE in the diets were compared to validate the additivity of effective energy predicted from simulated digestion method. The results showed that the coefficients of determination (R²) of the linear regression model of in vivo DE, ME and NE calculated from GB/T 939235—2020 against effective energy predicted from EHGE combined with CP and ADF of 17 feed ingredients were 0.774, 0.778 and 0.870, respectively. Regression diagnostic analysis indicated that rice bran, wheat bran and corn germ meal deviated from other 14 feed ingredients in the linear relationship between the in vivo and predicted values (DFFITS>$ 2 \sqrt{\frac{p}{n}} $). Excluding the above 3 samples, the R² of the linear regression of in vivo effective energy calculated from GB/T 939235—2020 on predicted values were greater than 0.93. The linear regression of determined EHGE on weighted calculation values and the predicted DE, ME and NE on weighted calculation values were consistent to the line of Y=X (R²>0.95, P < 0.01). These results indicate that the simulated digestion method can accurately predict the effective energy of 14 feed ingredients, but underestimate the effective energy of rice bran and wheat bran, whereas overestimate the DE and ME of corn germ meal. The EHGE determined by simulated digestion method and the DE, ME, NE which predicted from EHGE all have good additivity.

The aim of this study is to investigate the effects of three rearing systems on the growth performance, immune function, intestinal morphology, and cecal microbiota of Lueyang black-bone chickens. In this study, ninety 70-day-old healthy Lueyang black-bone chickens from the same batch of chicken flocks were randomly divided into 3 groups: cage rearing (CR), net-flat rearing (NF), and free-range rearing (FR) groups, each group had 5 replicates with 6 chickens per replicate (half of male and female). A one-week pre-experiment was conducted, and all experimental chickens were fed the same basic diet and had free access to feed and water. The body weight was collected every 7 days, the experimental chickens were raised to 119 days old, total feed consumption was recorded to calculate the average daily feed intake (ADFI), average daily gain (ADG) and feed to gain raito (F/G). Samples including serum, small intestine and intestinal mucosa (duodenum, jejunum, and ileum), and cecal contents were collected. The results showed that the average body weight of male and female chickens in NF and CR groups was significantly higher than FR groups (P < 0.01), the body weight of CR hens in the later stage of the experiment (105 to 119 day-old) was significantly higher than NF and FR groups (P < 0.01). The average daily feed intake (ADFI) and average daily gain (ADG) of NF and CR chickens were higher than FR chickens (P < 0.001, P=0.005), and the ratio of feed to gain (F/G) of FR chickens is significantly higher than CR and NF groups (P=0.002). The results of immune performance testing using ELISA kits showed that there was no significant difference in immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin G (IgG) and secretory immunoglobulin A (sIgA) among the roosters under the three rearing systems (P>0.05), while serum IgA of NF hens was significantly higher than CR and FR hens (P < 0.05). The results of intestinal morphology showed that the villus height of duodenum, jejunum, and ileum, as well as the ratio of villus height to crypt depth, were significantly higher in the NF and CR groups than FR group (P < 0.05). The 16S sequencing results of cecal contents indicated that the FR group increased the relative abundance of Proteobacteria, Epsilonbacteraeota, and Spirochaetes and decreased Bacteroidetes and Firmicutes at the phylum level. The NF group increased the relative abundance of Actinobacteria, Verrucomicrobia, and Chloroflexi. The CR group increased the relative abundance of Bacteroidetes and Firmicutes. At the genus level, the relative abundance of Escherichia-Shigella, Helicobacter, Enterococcus and Campylobacter increased, while Faecalibacterium, Bacteroides, and Akkermansia decreased in the FR group. The CR group increased the relative abundance of Bacteroides and Rikenellaceae_RC9_gut_group. In summary, the growth performance and intestine of Lueyang black-bone chickens were better under cage rearing and net-flat rearing, and net-flat rearing can improve immune performance. Therefore, net-flat rearing is a more proper rearing system for Lueyang black-bone chickens.

This study aimed to purify the cathay topotype of foot-and-mouth disease virus (FMDV) type O and prepare monoclonal antibody to provide biological materials for the study of novel cathay strain of foot-and-mouth disease. The antigen of cathay strain of FMDV type O was purified by PEG precipitation method and immunized BALB/c mice. Hybridoma cells were prepared by fusion of spleen cells and SP2/0 cells. Positive cells were screened by indirect ELISA and subcloned by limited dilution method. Two hybridoma cells, named 10E6 and 11C7, which were able to secrete monoclonal antibodies specifically against O-type FMDV Cathay strain were obtained. Additivity assay showed that the additivity rate of the two mAbs was 49.45%, and different epitopes were identified.Indirect ELISA and IFA showed that the two strains had good reactivity with O-type FMDV Cathay strain. The results of monoclonal antibody detection showed that the two monoclonal antibodies could specifically recognize Cathay FMDV strains and did not cross-react with other FMDV strains. The results of antibody subtype identification showed that the light chain of 10E6 monoclonal antibody was Kappa chain, the light chain of 11C7 monoclonal antibody was Lamda chain, and the heavy chain type of both strains was IgG2a. The results showed that two monoclonal antibodies specifically binding to O-type FMDV Cathay topological strain were successfully prepared in this study. Both monoclonal antibodies had good reactivity and specificity. Two monoclonal antibodies were used to establish a double antibody sandwich ELISA method for detecting O-type FMDV Cathay strain. The ELISA method had good specificity, repeatability and sensitivity, which laid a foundation for the rapid diagnosis, control and research of O-type foot and mouth disease virus Cathay strain.

This study was designed to establish an antibody detection method for porcine rotavirus (PoRV). We utilized the truncated VP6* (aa149-332) protein of PoRV as the detection antigen to develop an indirect ELISA detection method for PoRV antibodies. The truncated recombinant VP6* (aa149-332) exists in two forms: inclusion bodies and soluble, with a size of 22.5 ku. The optimized reaction conditions of the ELISA were as follows: the optimal coating antigen concentration, coating time and temperature were found to be 25 ng per well, and left overnight at 4 ℃; the plates were blocked with 5% skimmed milk at 37 ℃ for 2 hours; the optimal dilution of test serum and the secondary antibody were found to be 1 ∶400 and 1 ∶24 000, respectively. The optimal incubation time and temperature for test serum and the secondary antibody were 30 minutes and 37 ℃, respectively, and the color development time was 15 minutes. Testing 30 negative sera determined the cutoff value at OD_{450 nm}=0.418, the maximum dilution of detectable antibodies is 1 ∶3 200. The intra-batch and inter-batch coefficient of variation were both less than 10%, and it exhibited good specificity. The agreement rate with Western Blot results for 28 sera was 96.42%. The correlation coefficient (R²) between ELISA OD_{450 nm} values and neutralizing antibody log2 values was 0.878 5. In summary, the indirect ELISA established in this study for detecting porcine rotavirus antibodies has high specificity and sensitivity, making it applicable for clinical sample testing of porcine rotavirus.

To elucidate the impact of interferon regulatory factors (IRFs) on the proliferation of porcine pseudorabies virus (PRV), this study utilized shRNA technology to establish a PK15 cell line with the targeted knockdown of IRF1-9 genes. The knockdown efficiency was verified, and the proliferation of PRV subsequent to the knockdown was assessed using flow cytometry and titration assays. Additionally, the mRNA expression levels of PRV-gB, IFN-β, ISG-15, and IL-6 in PRV-infected cells were quantified by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The expression of the gB protein in PRV-infected cells was analyzed by Western blotting. The knockdown efficiency assay demonstrated a significant reduction in the expression of IRF1-9 mRNA in PK15 cells. The results from flow cytometry and titration assays indicated that the knockdown of IRF1-9 genes facilitated the proliferation of PRV. Furthermore, RT-qPCR and Western blot results revealed a significant increase in the mRNA and protein expression levels of PRV-gB following the knockdown of IRF1-9 genes. The analysis of mRNA expression levels of cellular inflammatory factors showed that the knockdown of IRF1-9 inhibited the PRV-induced expression of IFN-β, ISG-15, and IL-6 at the mRNA level. In conclusion, these findings suggest that IRF1-9 serves as a host restriction factor, limiting the replication of PRV within PK-15 cells.

The aim of this study is to use lentiviral packaging knockdown technology to construct lentiviral plasmids for knocking down tumor susceptibility gene 101 (TSG101) and stably transfect PK15 cell lines, and to verify the impact of this knockdown cell line on PRV infection. A recombinant lentivirus was successfully constructed and screened for the TSG101 gene, and PK15 cells were infected with the obtained recombinant lentivirus. Puromycin was used for screening to obtain PK15 cell lines that knocked down the TSG101 gene. Perform editing efficiency testing on the constructed cell line using Real time PCR and Western blot methods; Use CCK-8 method to detect cell viability and growth status of the selected cell lines; Verify the effect of this cell line on PRV replication through flow cytometry, Real time PCR, Western blot, and progeny virus titer methods; Finally, experiments were conducted on the adsorption, entry, and replication stages of PRV to explore the impact of knocking down the TSG101 gene on PRV infection. The results showed that: 1) the expression of TSG101 was significantly reduced in the cell line constructed in this study, and the cell line was named sh-TSG101 cell line; 2) The results of cell viability testing showed that knocking down the TSG101 gene had no significant effect on cell viability and growth; 3) Using PRV-GFP and PRV-QXX to infect sh-TSG101, in vitro experiments have shown that knocking down TSG101 has a significant inhibitory effect on PRV proliferation. 4) The adsorption, entry, and replication experiments of the virus have shown that knocking down TSG101 has a significant inhibitory effect on the replication stage of PRV. In summary, this study successfully constructed PK15 cell lines with TSG101 gene knockdown. Knocking down TSG101 in vitro can significantly inhibit PRV proliferation, providing new ideas for the prevention and control of DNA viral diseases such as PRV, and laying a foundation for further exploring the molecular mechanism of TSG101 regulating PRV infection.