Changes in maternal nutrition during gestation will affect the growth and development of the fetus. Placenta is an important interface for gas, nutrition and metabolite communication between maternal and fetus. The mammalian placental nutrition sensing system responds to the changes in maternal and fetal signals to ensure maternal health and promote the fetal growth and development. In view of its important role of the placental nutrition sensing system to mammalian reproduction, this article summarizes the effects of relevant signaling pathways including mammalian target of rapamycin (mTOR), AMP-activated protein kinase (AMPK), hexosamine signaling pathway (Hexosamine), hlycogen synthase kinase 3 (GSK-3), insulin/insulin-like growth factor signaling pathway (IIS) and others on placental nutrition sensing and placental nutrient distribution to response nutrient changes in dam, subsequently to influence fetal development during pregnancy. All above are expected to provide theoretical basis for the breeding of mammals.

Gut microbiota are involved in nutrient metabolism and affect the health and development of pigs. Disturbed gut microbiota can cause diarrhea and immune response in pigs. Therefore, gut microbiota play a vital role in pig health. This article reviwed the distribution of gut microbiota in different development stages of piglets, the influence mechanism of gut microbiota metabolites on gut health, and the relationship between gut microbiota and gut barrier. As well discussed the current research progress of gut health and future research direction, aiming to provide theoretical reference to modulate intestinal networks to maintain swine health.

The RNA binding protein HuR (human antigen R), also known as ELAV like RNA binding protein 1 (ELAV1), is an important RNA binding protein widely expressed in various tissues of the body, which is involved in various biological activities through the regulation of pre-mRNA splicing, polyadenylation, as well as mRNA stability and translational efficiency. Studies have shown that RNA binding proteins are involved in the regulation of muscle growth and development, in which HuR is involved in regulating myogenesis and the occurrence of muscle diseases mainly by affecting the stability and translation of target mRNAs. Combined with the related research of HuR in recent years, this paper reviews the biological characteristics, main functions and modes of action of HuR, and its regulatory role in muscle growth and development and related diseases, in order to provide reference for the further study of the role of HuR in the regulation of muscle growth and development.

Malaria is a zoonosis caused by Plasmodium which belongs to Apicomplexan. Plasmodium can not only infect human beings, but also poultries, mice, cynomolgus macaques and many kinds of animals, among which Plasmodium gallinaceum and rodent malaria have a great impact on animal husbandry. Plasmodium requires a strict gene regulation to complete its complex life cycle and transcription factors play very essential roles in regulating gene expression. Up to now, apicomplexan AP2 (ApiAP2) family is the only candidate that appears as transcription factors in Apicomplexan. On the basis of summarizing the previous studies, this article predicts the regulatory mechanism that the function of proteins is unknown in ApiAP2 family of Plasmodium falciparum, also explores the prospect of the post-translational modification in ApiAP2 family, which provides reference for animal husbandry to develop vaccine of protozoal diseases.

It is an important aspect to raise the number of eggs and control the appropriate egg weight by genetic way in the breeding of white-feather broilers in China. In order to explore the genome selection model suitable for the breeding of Chinese white-feather broilers, this study took 2 474 white-feather broilers, mainly analyzed the prediction accuracy of the machine learning algorithms KAML, BLUP (including:PBLUP, GBLUP, SSGBLUP) and Bayes (Bayes A, Bayes B and Bayes Cπ) methods in predicting egg number and egg weight traits. And the prediction accuracy was evaluated by 5-fold cross validation. The heritability and genetic correlation of the traits of egg number and egg weight were estimated using pedigree and genomic information. The results showed that the heritability of egg number was 0.061-0.16, which was a low heritability trait. The heritability of egg weight was 0.28-0.39, which was a medium heritability trait. The egg number and egg weight had a medium negative genetic correlation (-0.518——0.184). There was a strong positive genetic correlation (0.736-0.998) between the number of eggs laid at different stages. The accuracy of breeding value estimation for egg number (43 weeks) and egg weight (52 weeks)predicted by different models showed that the prediction accuracy of KAML method were 0.115 and 0.266, respectively, which were significantly different from that of GBLUP method (0.118 and 0.283) and SSGBLUP method (0.136 and 0.259), and were significantly lower than that of Bayes method (accuracy:0.230-0.239, 0.336-0.340). PBLUP method had the lowest prediction accuracy (0.095 and 0.246, respectively). Therefore, the Bayes method for the egg number and egg weight traits of white-feather broilers will achieve the highest accuracy of breeding value estimation.

The purpose of this study was to identify candidate genes affecting drip loss of pork, and to lay a foundation for meat quality breeding of pigs. The experimental population in this study was 478 healthy Suhuai pigs with an average age of 237.95 days, including 290 castrated boars and 188 sows. The longissimus dorsi muscle samples of all individuals were collected, and then the drip loss (DL) phenotype data were measured by hanging bag method to calculate the estimated breeding value (EBV) of drip loss, and Suhuai pigs with top 10% (N=48) and bottom 10% (N=48) of EBV_DL were selected for genotyping using the GeneSeek GGP-Porcine 80 K SNP BeadChip (Illumnia). The fixation index (Fst) and integrated haplotype score (iHS) were used to detect the whole genome selection signals of Suhuai pigs. We selected SNP sites with iHS value in the top 5% and Fst ≥ 0.15 as the selected SNPs, then gene annotation was performed within the region of 50 kb upstream and downstream of the selected SNPs, and all genes were analyzed for KEGG and GO enrichment to identify candidate genes associated with drip loss of pork. After the quality control of chip typing data, 51 705 valid SNPs from 96 samples were used for subsequent analysis. A total of 175 SNPs were screened by Fst and iHS selective signal analysis, they were mainly located on chromosome 1, 6, 7 and 11, of which only 27 SNPs were located in the QTL regions that have been reported to affect the drip loss of pork. Gene annotations of the area around the selected SNPs showed that 175 significant SNPs were involved 73 genes. Among these genes, several genes have been reported to be related to muscle development and cell oxidative stress, including PACRG, EZR, MRTFA, LCP1 and VKORC1L1. The 5 genes were newly discovered functional candidate genes that were related to the drip loss of pork. Then, we genotyped 3 SNPs located on the intron of the functional candidate genes and on the QTL region, and analyzed the correlation between genotypes of the 3 SNPs and the drip loss in the whole Suhuai pig population. The results showed that rs340037952 located on the MRTFA gene was significantly associated with drip loss in Suhuai pig population (P<0.05), and rs320624660 located on the VKORC1L1 gene was extremely significantly associated with drip loss in Suhuai pig population (P<0.01). In this study, 175 selected SNPs were found through selection signal analysis, 5 candidate genes affecting drip loss were identified by gene function annotation, and 2 SNPs (rs340037952 and rs320624660) significantly associated with drip loss in Suhuai pigs population were identified on MRTFA and VKORC1L1 genes, which provided a preliminary basis for the breeding of drip loss in pigs.

This study aimed to evaluate the genetic parameters of type traits of Holstein cows in Shandong province and provide reference for developing breeding programs. Based on 31 963 primiparous Chinese Holstein cows which had 20 type traits data in 144 farms in Shandong province from 2010 to 2020, in which the linear score changed to functional score,the genetic parameters for 20 type traits were analyzed by AI-REML and EM algorithm of the DMU software combined with animal model considering herd, lactation month, first calving age, identification appraisers as fixed effects,and individual additive genetic effect as random effect. The results showed that the heritability of type traits belonged to a medium-low level with the estimated values ranging from 0.049 (set of rear legs) to 0.282 (angularity); The genetic correlation between traits ranged from -0.558 (fore teat placement and udder depth) to 0.717 (heel depth and foot angle). The genetic correlation between body volume traits ranged from 0.118 (body depth and stature) to 0.461 (chest width and loin strength); The genetic correlation between pin setting and pin width was -0.251. The genetic correlation between limb and hoof traits ranged from -0.035 (heel depth and rear leg-rear view) to 0.717 (heel depth and foot angle); The genetic correlation between lactation system traits ranged from -0.558 (fore teat placement and udder depth) to 0.587 (median suspensory and fore attachment). In addition, the standard error of heritability estimation of type traits was the smallest when the number of generations of pedigree was 3, which might be due to the limitation of pedigree data integrity, and further verification was needed.It was beneficial to improve the production performance of dairy cows by strengthening the selection of the traits with high heritability and strong genetic correlation with lactation system. In addition, in the data of this study, the standard error of heritability estimated by the first three generations pedigree was the smallest, so it may be better to estimate genetic parameters by the first three generations pedigree.

The study aimed to screen the potential landmark differential metabolites in milk with different milk fat levels. In this study, 245 fresh milk samples (4:3:3 mixture) were collected from the early, middle and late shifts of healthy first-calf Holstein cows with similar weight and age in the middle and late stages of lactation (180-210 d) from the Maosheng pasture of Helanshan in Ningxia state farm. After DHI determination, 26 samples with the number of somatic cells less than 200 000 pcs·mL^-1 and extreme differences in milk fat percentage were screened. Among them, the milk with higher milk fat percentage than 4.4% was the high milk fat percentage group (HF group, 13 samples), and the milk with less milk fat percentage than 3.0% was the low milk fat percentage group (LF group, 13 samples). The samples were then subjected to metabolomic analysis using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). The results of PLS-DA showed that, compared with LF group, the metabolic profile of HF group changed, and 343 metabolites were identified in HF and LF groups. According to VIP value (VIP>1) and univariate statistical analysis (P<0.05), 60 significantly differential metabolites were screened out in positive and negative ion modes (P<0.05). Among them, according to P<0.5 and FC>2.0 and P<0.5 and FC<0.5, the content of 15 metabolites in milk samples of HF group was higher than that of LF group, and the content of 6 metabolites was lower than that of LF group.Further, through ROC curve, it was found that there were 18 kinds of differential metabolites which had remarkable distinguishing ability to the two groups of milk, among which the differential metabolites with AUC>0.85 were N-oleoylglycine, cortisol, δ-tocopherol and PC (14:0e/9:0). The results showed that there were 60 metabolites with significant differences in different milk fat levels, and the metabolites N-oleoylglycine, cortisol, δ-tocopherol and PC (14:0e/9:0) could be used as potential landmark metabolites of high milk fat percentage. The results of this study provide valuable theoretical basis for milk fat synthesis of dairy cows, and also provide data for studying the lactation process of dairy cows.

This study aimed to explore the function of BgIGFBP4 in the proliferation of yak hepatocyte and the development of mice. The prokaryotic expression vectors pET-28a-BgIGFBP4 was constructed, induced and identified. Hepatocytes were treated with 0.002, 0.02, 0.2, 2, 20 μg·mL^-1 of BgIGFBP4 protein. The effects of BgIGFBP4 protein concentrations on the proliferation of hepatocytes were detected by CCK8 kit and colony forming assay. According to the results of the previous experiment, the optimal concentration of BgIGFBP4 was selected to treat hepatocytes for different time, and the changes of hepatocyte activity, growth-like hormone of hepatocyte supernatant and PI3K-Akt signaling pathway were detected at 24, 48 and 72 h. Healthy male KM mice aged 30 days ((18 ±1)g) were selected and divided into two groups (40 mice per group). The experimental group were fed with 100 μL 50 μg·mL^-1 BgIGFBP4 protein every two days. And the control group was fed with the same amount of 0.9% sterile saline. Before the experiment, the mice were starved for 12 h. The test period was 28 days. The growth performance indexes, serum growth-like hormone and liver PI3K-Akt signaling pathway were detected at 28 days. Prokaryotic expression indicated that a 28.86 ku recombinant protein was obtained and identified. The activities of hepatocytes and the colony formation of hepatocytes could be optimized by 2 μg·mL^-1 BgIGFBP4 protein. Compared with the control group, the GH and VEGF concentrations in supernatant of yak hepatocytes in the experimental group were significantly increased (P<0.05), and the transcription levels of cell proliferation related genes ERBB2, IRS1, PIK3R1, AKT1, RAF1 and MAPK3 in PI3K-Akt signaling pathway were significantly increased (P<0.05). In comparison with the control group, the average daily gain of the experimental group mice was significantly increased, the feed to weight ratio was significantly decreased, and the liver, spleen, lung, kidney and intestine organ indexes were significantly increased (P<0.05). The contents of serum GH, ISN and VEGF were significantly higher than those of control (P<0.05), and the transcription levels of cell proliferation related genes ERBB2, IRS1, PIK3R1, AKT1, RAF1 and MAPK3 in PI3K-Akt signaling pathway were significantly increased (P<0.05). In conclusion, BgIGFBP4 can promote the proliferation of yak hepatocytes and the growth of mice. This study provides reference for further study of the role of IGFBP4 in yak liver growth and development.

The study aimed to explore the maternal genetic diversity, population structure, cluster relationship and genetic background of wild yak and local yak breeds in Qinghai at molecular level. The 22 mitogenome sequences of 4 local yak breeds in Qinghai (Qinghai Plateau, Huanhu, Xueduo and Yushu) were obtained, and 142 corresponding sequences from wild yak and the above 4 local yak breeds in Qinghai were downloaded from GenBank. A total of 164 mitogenome sequences were comprehensively analyzed by using BioEdit 7.2.5, Arlequin 3.11 and Network 10.1 softwares. The results showed that:1) A total of 115 haplotypes were identified based on nucleotide variation, among which 22 haplotypes were found in wild yak and 93 haplotypes were detected in Qinghai yak breeds. The 22, 26, 18, 23 and 19 haplotypes were detected in wild yak, Qinghai Plateau, Huanhu, Xueduo and Yushu yak breeds, respectively. Genetic diversity analysis showed that the haplotype diversity of wild yak was the highest (0.992 8±0.014 4), which was higher than that of 4 local yak breeds in Qinghai (0.973 1±0.007 7). The haplotype diversities of 4 local yak breeds were 0.988 5±0.012 6 (Xueduo yak), 0.975 8±0.018 7 (Yushu yak), 0.973 0±0.016 6 (Qinghai Plateau yak) and 0.939 3±0.027 8 (Huanhu yak), respectively. 2) The fixed index (F_ST) value between wild yak and Huanhu yak was the highest (0.041 2), while the lowest (-0.008 8) between wild yak and Yushu yak. Among the 4 local yak breeds, the F_ST value between Xuduo yak and Qinghai Plateau yak was the highest (0.035 8) and the differentiation degree was the highest, while the F_ST value between Xuduo yak and Huanhu yak was the lowest (0.011 2), inferring the lowest differentiation degree. 3) The clustering analysis showed that each of the 4 yak breeds was divided into one category, suggesting that there were significant maternal genetic differences among them. In contrast, the clustering of Huanhu and Xueduo yak was closer, while the clustering of Qinghai Plateau yak and Yushu yak was also closer. The clustering relationship between wild yak and Yushu yak was closer. The clustering results among breeds (populations) was consistent with their differentiation degree and geographical distribution. 4) Phylogenetic analysis showed that 115 haplotypes were distributed in 3 maternal lineages (Mt-Ⅰ, Mt-Ⅱ and Mt-Ⅲ). The proportion of Mt-Ⅰ clade was 72.17%, consisting of 4 haplogroups (A, B, E and F), and Mt-Ⅱ clade consisted of 3 haplogroups (C, D and H), accounting for 26.09%. Mt-Ⅲ clade contained only G haplogroup, which was owned by Xueduo yak and wild yak, accounting for 1.74%, suggesting that yak had 3 maternal origins. In summary, the wild yak and the 4 local yak breeds in Qinghai Province all have rich maternal genetic diversity, and the diversity levels from high to low are the wild yak, Xueduo yak, Yushu yak, Qinghai plateau yak and Huanhu yak. The genetic differentiations among the 5 yak breeds (population) are weak, and each breed(population) had unique maternal genetic information, there are significant maternal genetic difference among them. The wild yak and Qinghai domestic yak breeds are composed of 3 maternal lineages, and it is speculated that there are 3 maternal origins in yak.

The purpose of this experiment was to reveal the variety source and population genetic structure of horse population in Kangxi grassland. The blood samples of 60 local horses with good health, moderate weight and indistinguishable male and female between the ages of 3 and 6 were collected. Four foreign horse breeds such as thoroughbred horses and one local horse breed in China were used as controls. The alleles of 12 microsatellite loci on chromosomes were detected by designing primers and extracting genomic DNA combined with PCR-STR. The genetic diversity parameters, population differentiation, bottleneck effect and population structure were analyzed. The experiment was divided into 6 groups according to the number of populations, with one repetition in each group. Each repetition was based on the sample size of this group. After analyzing the genetic parameters of 6 horse populations, the results showed that 221 alleles were detected, and the average Shannon index was 1.691; The number of effective alleles (Ne) ranged from 3.649 to 5.397; The expected heterozygosity (He) was 0.681-0.798; The observed heterozygosity (Ho) ranged from 0.632 to 0.780; The average polymorphism information content (PIC) ranged from 0.643 to 0.772. These results showed that the 6 populations had high genetic diversity. Microsatellite DNA locus linkage disequilibrium and Hardy-Weinberg equilibrium analysis showed that the P value of most loci was greater than the correction value (P>0.006 5), indicating that many loci were in Hardy-Weinberg and linkage equilibrium. The population differentiation coefficient (Fst) among populations showed that the degree of differentiation among populations was low (Fst<0.15). Based on the Mantel correlation test between Nei's genetic distance and geographical distance, there was a positive correlation between them (R=0.502), but it did not reach a significant level (P=0.310). The bottleneck effect analysis of horse populations showed that the horse populations in this area were affected by the bottleneck effect, and the P value was very significant (P_(IAM)<0.01), indicating a large-scale reduction in the number of the horse population in history. Through FCA factor analysis, UPGMA tree based on Nei's standard genetic distance and Structure Bayesian cluster analysis, it is found that the horse population in this area was clustered with thoroughbred horses and warm blood horses, indicating that the population was most likely to be mainly from warm blood horses and thoroughbred horses. These results reveal that horses in Kangxi grassland have high genetic diversity, and the lineage of the local horse population is similar to that of thoroughbred horses and warm blood horses, which lays a solid foundation for the evaluation, development and utilization of local horse genetic resources.

In this study, plasma metabolomics change features of Mongolian horses before and after endurance exercise were analyzed by ¹H-NMR technology. Six castrated Mongolian male horses, whose age, body height, body length, heart girth, cannon circumference were (5.33±0.82) years, (136.83±0.75) cm, (143.33±2.58) cm, (157.17±2.04) cm, (18.45±0.27) cm, respectively, were selected to do the endurance exercise of 15 and 30 km by trot pace. In total, 24 blood samples from the 6 Mongolian horses were collected before and after 15 and 30 km distance training, respectively. The spectrum information of plasma metabolite were measured by Bruker AV III ¹H-NMR spectrometer with the resonance frequency of 600.13 MHz. The metabolic patterns and differential metabolic markers between groups were identified using PLS-DA package of R programme and one-dimensional ANOVA test of SPSS 20.0 software, respectively. The results showed that 47 distinct plasma metabolites were identified in 6 Mongolian horses before and after two different loads (15 and 30 km) of exercise. In which, 21 differential plasma metabolites were observed before and after 15 km loading exercise. After 15 km loading exercise, the metabolite concentration of ethanol and mannose decreased; However, the metabolite concentration of glucose, acetoacetate, pyruvate, lactate, creatinine, glycerol, valine, alanine, leucine, tyrosine, phenylalanine, threonine, isobutyrate, methionine, 2-hydroxyisobutyrate, O-acetylcar-nitine, 3-hydroxyisobutyrate, 3-methyl-2-oxovalerat and 3-hydroxyisovalerate increased. Ten differential plasm metabolites were detected before and after 30 km loading exercise. After 30 km loading exercise, the metabolite concentration of ethanol, glucose, lysine, glycine, proline, glutamine, τ-methylhistidine and valine decreased; The metabolite concentration of methanol and creatine increased. Comparison of the metabolite concentration after 15 and 30 km loading exercise showed that alanine, citrate, acetate, lysine, malonate, acetone, 2-hydroxyisovalerate, 2-hydroxyisobutyrate, pantothen, betaine and isobutyrate decreased, lactate, dimethyl sulfone, pyruvate, N-phenylacetylglycine, hippurate, methanol and 3-hydroxyisovalerate increased. In total, 47 distinct plasma metabolites were identified and the types of differential metabolites were significantly different in 6 Mongolian horses before and after 15 and 30 km exercise. The energy supply mode of the 30 km exercise in Mongolian horses is mainly aerobic metabolism of fatty acids, whereas, that of the 15 km exercise is mainly anaerobic metabolism of glycolysis, while ketone body metabolism was a transitional stage of energy supply mode conversion. The results provided a theoretical basis for the training and breeding of endurance racehorses in China.

The objective of this study was to explore genetic diversity and population structure of Kunming dog, which is the only domesticated and widely used as working dog in China.The blood samples of 16 Kunming dogs (3 strains), 4 Malinois dogs and 4 German Shepherds were collected and genomic DNA was extracted. The genetic population structure of the 3 breeds of police dogs was analyzed using principal component analysis (PCA), STRUCTURE and neighboring (NJ) trees by Illumina Caninehd Beadchip chip. Genomic selection footprints analysis was used to identify candidate genes that were selected during domestication and improvement of Kunming dog. The results showed that 86 270 SNPs were selected for analysis according to the quality control standards of chip data. Population STRUCTURE analysis showed that German Shepherd was completely distinguishable from other breeds when k=2. Malinois could be distinguished from other breeds when k=3, but there were some heterozygous German Shepherds in Kunming dogs. Three police dog breeds could be clearly separated by PCA analysis and NJ tree analysis. After setting a sliding window of 500 kb on the autosomes and annotating these regions, 22 candidate genes that may be selected during the domestication and improvement of Kunming dog.The first category was the genes and proteins which participated in adenylate cyclase-activating G-protein coupled receptor signaling pathway.Another type of gene had the function of polymerizing and stabilizing microtubules in the growth cones of neuronal axons, and affecting the growth of axons and leading protrusions. The results of this study investigated the genetic relationship between Kunming dog and other police dogs.It provide an important reference for exploring the adaptive mechanisms of Kunming dogs, such as learning, memory and stress stimulation, which are produced by strong artificial selection.

The study focused on screening key genes of embryo implantation in early pregnancy through high throughput sequencing of goat uterine horn tissue before and after embryo implantation. Sixteen multiparous female Nubian goats (Capra hircus) with similar weights((44.76±3.49) kg) and age(2-4 years old) were selected for simultaneous estrus and artificial insemination. On the 15th day (D15) and 30th day (D30) after mating, 3 goats were randomly selected and sacrificed by carotid bloodletting, respectively. The uterine horn tissues were collected after sacrifice for Illumina HiSeq high fluxtranscriptome sequencing (RNA-Seq). Differentially expressed genes (DEGs) were screened from the sequencing results, and their functions were annotated. Then, the regulatory genes related to embryo attachment were further screened through literature search. Finally, fluorescent quantitative PCR (qRT-PCR) was used to perform expression verification analysis of the selected genes. Comparative analysis of D15 and D30 uterine horn tissue transcripts obtained 2 000 DEGs, including 620 up-regulated genes and 1 380 down-regulated genes. GO functional cluster analysis was divided into 3 major categories and 52 groups, including 17 groups of cellular components, 23 groups of biological processes, and 12 groups of molecular functions, which obtained some important biological pathways such as cell connection and proliferation, biological adhesion and regulation, molecular activity and transduction, etc. Taking the expression level of genes on D15 as the standard, the gene MGP and TAGLN related to embryo attachment were screened from the 10 genes with the highest expression. From the top 10 differentially expressed genes with the largest up-regulation and down-regulation, the gene PAG-3, PAG-8 and PAG-12 related to pregnancy-associated glycoprotein synthesis and secretion, GHRHR related to growth factor binding and growth hormone releasing hormone receptor activity and IGFBP1 related to insulin-like growth factor binding protein were obtained. The results of qRT-PCR showed that the change trend of the expression of 6 randomly selected genes was consistent with the results of RNA-Seq. The obtained gene MGP, TAGLN, PAG-3, PAG-8, PAG-12, GHRHR, IGFBP1 may play an important role in the implantation and development of embryos in Nubian goat.

This study was designed to explore the alleviating effect and mechanism of a strain of Saccharomyces cerevisiae and two strains of Diutina rugosa from rumen on subacute ruminal acidosis (SARA) in sheep. In order to provide strains and a theoretical basis for developing probiotics to prevent SARA in sheep. Sixty two-month-old weaned Dubo sheep (♂)×Hu sheep (♀) F₁ generations were selected as experimental animals. SARA was successfully induced in forty sheep by gradually increasing the diet concentrate-to-roughage ratio. SARA sheep were divided into 4 groups (n=10):SARA group;Saccharomyces cerevisiae ACCC 21162 (SC) group;Diutina rugosa N09 (DR1)group; Diutina rugosa N07 (DR2)group. All four groups were fed a diet with a concentrate to roughage ratio of 90:10. And SC,DR1 and DR2 groups were respectively gavaged with 100 mL Saccharomyces cerevisiae ACCC 21162,Diutina rugosa N09 and Diutina rugosa N07 after morning feeding.The control group (CON, n=10) was fed 50:50 diet at all times. The ruminal pH was measured on the 1, 3, 7, and 10 d after adding yeasts, respectively. On 10 d after adding yeasts, rumen microflora, abnormal metabolites, and blood gas were measured. The results showed that:1) Ruminal pH in the yeast groups was significantly higher than that in the SARA group on the 3rd day (P<0.05), and SARA was effectively relieved in yeast groups. 2) The optimum bacteria in SC and CON groups were Lactobacillus and unidentified Prevotellaceae, respectively, while in the other groups it was unidentified Ruminococcaceae. In the yeast groups, SC group had the highest richness index and DR2 group had the highest diversity index. 3) The rumen and blood lactic acid and rumen histamine in the yeast groups were significantly lower than those in the SARA group (P<0.05). 4) Blood pH and base excess in SC and DR2 groups were extremely significantly higher than those in the SARA group (P<0.01). The blood carbon dioxide partial pressure, total carbon dioxide, and bicarbonate concentration in the yeast groups were significantly higher than those in the SARA group (P<0.05). 5) There was a significantly positive correlation between ruminal pH and actual bicarbonate in the blood (P<0.05), and a significant negative correlation between rumen lactic acid and Chao 1 index of rumen microflora (P<0.05). These results indicated that three yeasts had the effects on improving the abundance of rumen microflora, reducing rumen and blood lactic acid, alleviating rumen inflammation and body acidosis.

The study aimed to screen out the genes related to lipid metabolism in breast muscle of Bian chickens affected by conjugated linoleic acids(CLA) through transcriptome sequencing technology, and provide the theoretical basis for the mechanism of dietary CLA regulating the lipid metabolism. In this experiment, 180 90-day-old healthy Bian chickens were randomly divided into 5 gourps with 3 replicates in each group, and chickens in different groups were fed diets added different proportions CLA 0% (control group), 0.5%, 1.0%, 1.5% and 2.0%, respectively, the pre-feeding period lasted for 1 week followed by an experimental period of 6 weeks. After the feeding experiment, breast muscles were collected for transcriptome sequencing. DESeq2 software was used for differential expression analysis of the sequencing data, the differentially expressed genes were detected by GO function and KEGG pathway enrichment analysis, and differentially expressed genes related to lipid metabolism in breast muscle were screened out. the differentially expressed genes were verified by qPCR.Through analyzing transcriptome sequencing data, a total of 1 229 differentially expressed genes were screened out, 594 genes were up-regulated and 635 genes were down-regulated. The results of 9 randomly selected differentially expressed genes by qPCR verification showed that the relative expression trend was consistent with the sequencing results. GO functional analysis found that differentially expressed genes were mainly concentrated in the biological process, including cellular process, single-organism process, biological regulation and metabolic process. KEGG pathway enrichment analysis showed that the differentially expressed genes in each experimental group were significantly enriched in different signaling pathways, mainly enriched in ECM-receptor interaction, focal adhesion, phagosome, apoptosis, regulation of actin cytoskeleton and cytokine-cytokine receptor interaction. Through GO and KEGG function annotation analysis, a total of 18 main differentially expressed genes involved in lipid metabolism were screened out, including MCAT, APOA1, PTGDS, ALDH3A2, PLTP, FABP3, FOXO1, UCP3 and FABP4, etc., which may play an important role in regulating the lipid metabolism in breast muscle of Bian chickens. In this study, transcriptome sequencing was used to screen the main regulatory genes in the process of CLA affecting lipid metabolism in breast muscles of Bian chicken, and the main biological processes and signaling pathways were found, which lays the foundation for the future study of the molecular mechanism of CLA affecting the lipid metabolism in breast muscle of Bian chickens.

The aim of this study was to investigate the effects of lighting rhythm on the growth performance, blood metabolites, meat quality and behavior of rabbits. One hundred and thirty five 35-day-old weaned male Hyla rabbits were randomly divided into 3 treatments with 15 replicates and 3 rabbits in each under the lighting photoperiods of 12 h light:12 h darkness (12L:12D), 24 h light (24L), and 24 h darkness (24D), respectively. The light intensity was 100 lx. The experimental period lasted for 35 days after 7 days of pre-trail. The results showed that compared with 12L:12D group, the average daily feed intake (ADFI), feed conversion rate (FCR) at 21-35 d, carcass yield, pH and cooked meat rate of longissimus lumborum in 24D group increased significantly (P<0.05), and the blood glucose concentration decreased significantly (P<0.05). The FCR and carcass yield of 24D group were the highest in all treatment groups (P<0.01). The leather index of 24L group was significantly lower than that of 12L:12D and 24D groups (P<0.01), while the albumin (ALB) and meat water loss rate were significantly higher than that of 12L:12D and 24D groups (P<0.01). There was no significant difference in meat color or conventional nutritive indexs among treatment groups (P>0.05). The duration of sitting behavior of the 24D group was the least (P<0.01), the frequency of gnawing behavior was lower than other groups(P<0.05), and the frequency of hyperactivity, rearing and standing behavior were the highest in all groups (P<0.05). The results showed that long-term dark environment could improve the growth performance and reduce the blood glucose concentration of rabbits. At the same time, rabbits showed more sociality, less fear and anxiety in the long-term darkness, having good welfare.

This study aimed to establish a blocking ELISA method for detection of African swine fever virus(ASFV) p72 protein antibodies. With the purified recombinant p72 protein as coating antigen, and the HRP labeled 6E5 antibody as the blocking antibody, a blocking ELISA method based on ASFV p72 protein was established after optimization of the reaction conditions. One hundred and nineteen clinical negative serum samples were detected using the present established method to determine the cut off value by the serum percentage of inhibition (PI) calculation. The criteria of the blocking ELISA:serum samples with PI ≥ 50% were judged as positive; the serum samples with PI ≤ 40% were judged as negative; and the serum samples with PI between 40% and 50% were judged as suspicious. This method had no cross reactions with the serum antibodies against PRV, PRRSV, CSFV, PCV2, SVA, FMDV, Escherichia coil, Pasteurella multocida, Glaesserrella parasuis and Actinobacillus pleuropeumoniae. The intra-assay and inter-assay variation coefficients were both less than 15%. Total 447 swine clinical serum samples were then detected simultaneously by the present established method and commercial ASFV antibody detection kit. The result showed that the relative sensitivity and specificity of the two methods were 95.3% and 94.5%, respectively, and the coincidence rate was 94.9%. In summary, the blocking ELISA method established in this study has high sensitivity and specificity, therefore it is suitable for ASFV diagnosis and epidemiological investigation.

African Swine fever (ASF), caused by infection with the ASF virus (ASFV), is one of the most serious viral diseases affecting pigs. It is featured by acute, febrile, hemorrhagic, high morbidity and mortality, etc. The aim of this paper is to develop an efficient and clinically convenient indirect ELISA antibody detection method for ASFV. Here, the ASFV-CP204L gene was amplified from positive samples, and the p30 protein was expressed through the pET-30a prokaryotic expression system. The expressed product was further purified with Ni-NTA, and the His protein was removed by enterokinase. Thus, an indirect ELISA method was established based on the purified recombinant tag-free p30 protein. An approximate 30 ku fusion p30 tag-free protein was observed. The results showed that the protein expressed in this study has good reactogenicity with ASF-positive pig serum. It was finally determined that the ELISA antigen coating concentration was 1 μg·mL^-1. The positive value (S/P) was more than 0.398 by the area under the ROC curve. The coefficients of inter-and intra-batches were less than 10%, indicating the good repeatability of the method. This method can detect at least 512-fold diluted standard positive serum samples. In the detection of experimentally infected sera, 80% of the samples were seroconversion on the 10th day. In this study, a total of 644 pig serum samples were collected. The results showed that the positive rates were 7.61%. Among them, the positive rates of antibodies in sows, gilts, piglets, nursery pigs and fattening pigs were 3.03%, 0%, 4.94%, 7.55% and 28.7%, respectively. The indirect ELISA method based on the tag-free ASFV-p30 protein has good specificity, sensitivity and reproducibility, and can be initially applied to the detection of antibodies of ASFV. It provides a technical tool for epidemiologically serological investigation of ASF.

The study aimed to explore the prevalence and genetic evolution of porcine circovirus type 3 (PCV3) in aborted fetuses. In this study, PCV3 detection, amplification and sequencing were performed on 680 samples of porcine abortion fetus in Hunan Province from 2015 to 2017, and the obtained sequences were analyzed by bioinformatics software for genetic evolution. The results showed that the positive rate of PCV3 in fetal samples of porcine abortion was 24.4% (166/680), and the positive rates from 2015 to 2017 were 18.2% (26/143), 22.7% (54/238) and 28.8% (86/299), respectively. A full-length genomic sequence of PCV3 was obtained from PCV3 positive samples, which was named PCV3/CN/Hunan-57 (GenBank accession No. MZ934695). Compared with the genome sequences of PCV3 strains at home and abroad, the homology was 97.8%-99.2%. The ORF2 gene sequences of five PCV3 strains were obtained, and their nucleotide and amino acid homology were 97.5%-98.3% and 96.7%-99.7%, respectively. Compared with the ORF2 gene sequences of reference strains in China and abroad, their nucleotide and amino acid homology were 96.3%-99.2% and 96.8%-100.0%, respectively. The genetic evolution tree was constructed based on the ORF2 gene sequence and multiple sequence alignment was performed. The obtained positive sequence belonged to PCV3a (1 strain) and PCV3c (4 strains), respectively, and the mutation sites of T100A, G113S and A184S were identified. This study showed that the infection rate of PCV3 in porcine aborted fetuses was high. There were different types of PCV3 infection in porcine aborted fetuses, which provided important reference information for further study of PCV3 genetic variation and its pathogenicity.

This study aims to investigate the protective effect of infected piglets which were immunized with different dose of inactivated porcine epidemic diarrhea virus (PEDV) vaccines. The number of infective virus particles and total virus particles of PEDV with different concentrations were determined, and the mice were immunized with different concentration vaccine prepared as antigen, respectively. The humoral and cellular immune production were determined by ELISA antibody detection method, neutralization test and ELISPOT method. Vaccine with appropriate antigen content was selected to immunize piglets, then the antibody was determined. The relationship between concentrated vaccine and protective effect was studied by challenge experiment. The results showed that, when the antigen dose was equal or greater than 8×10⁶ pfu·mL^-1, the inactive vaccine could effectively stimulate mice to produce humoral and cellular immunity. The piglets immunized with 2 mL inactivated PEDV vaccine containing 8×10⁶ pfu·mL^-1 antigen could resist diarrhea and continuous viral shedding caused by PEDV challenge. Compared with the total number of virus particles, the number of infectious virus particles was significantly correlated with antibody production (r=0.998 1), and neutralization titer was significantly correlated with piglet protection (r=0.974 7). PEDV inactivated vaccine can provide good immune protection, in which the number of infectious virus particles is the key factor to improve the antibody level. Antibody titer, as an index of humoral immunity, is an important reference for judging immune protection.

The purpose of this study is to obtain natural Listeria monocytogenes phage, provide new biological agents for the prevention and treatment of listeriosis, reduce the use of antimicrobial agents, and inhibit the production of antimicrobial resistance of pathogens. Using L. monocytogenes as the host, the slaughterhouse sewage was screened by double-layer agar plate method, and the phage was obtained. Application value of the phage were evaluated by transmission electron microscope, growth characteristics detection (temperature, pH, one-step growth curve, multiplicity of infection, the effect of organic solvents), genome restriction endonuclease digestion and whole genome sequencing. In this study, several strains of L. monocytogenes phage were isolated, and one of the phages with the stronger lytic ability and genetic stability was selected, and named LP8; as myotail phage under electron microscope, can lyse 18 strains of L. monocytogenes and 5 strains of Listeria welshimeri, it was determined that the multiplicity of infection of LP8 was 1, the optimum growth temperature was 45℃, and the pH was 7. During 6 kinds of organic solvents, only isoamyl alcohol could inactivate LP8 completely. The extracted genome was identified by restriction endonuclease digestion and identified as double-stranded DNA, the genome size was 87 038 bp, contained 120 coding genes, the cumulative length of coding genes was 76 326 bp, the average length of coding genes was 636 bp, and the proportion of coding region was 87.69%. In this study, the phage of L. monocytogenes was isolated, and its phage ability and application value were identified. Compared with other phages, the isolated LP8 stronger ability to adapt environmental changes and lyse bacterial. It provides a basis for the subsequent establishment of L. monocytogenes phage library and other applications of L. monocytogenes phage.

The purpose of this study was to analyze the function of EnOXIO1, an oxidoreductase came from Eimeria necatrix. Total RNA was extracted from the gametophyte of E. necatrix Yangzhou strain to amplify EnOXIO1 gene by using RT-PCR. After cloning and sequence analysis, the prokaryotic expression vector pET-28a(+)-EnOXIO1 was constructed and transformed into E. coli BL21 (DE3). The recombinant protein was expressed by inducing with IPTG, and its antigenicity and immunofluorescence localization was analyzed. Here we show that the full length of EnOXIO1 gene was 2 535 bp. The recombinant protein had a molecular weight of about 100 ku and mainly expressed in inclusion body. The expression level was about 0.5 mg·mL^-1 bacteria. Western blot analysis showed that the recombinant protein could be specifically recognized by 6×HIS labeled monoclonal antibody, the mouse anti-recombinant proteins polyclonal antibody, the recovery serum from chickens infected with E. necatrix, E. acervulina, and E. tenella sporulated oocysts, respectively. These results indicated that the recombinant protein had good antigenicity and cross-reactivity. The results of laser confocal immunofluorescence localization showed that the EnOXIO1 protein mainly existed in the wall forming body in the gametocyte and participated in the formation of the oocyst wall. In this study, EnOXIO1 protein was successfully cloned and expressed, and was located on gametocytes and oocyst wall, which laid a foundation for further analysis of the molecular mechanism of EnOXIO1 protein involved in the formation of oocyst wall, and provided important target antigens for the development of a novel immune-blocking anti-coccidiosis subunit vaccine.

To explore the molecular characteristics of Echinococcus granulosus BAG3 (Eg-BAG3) and EB1 (Eg-EB1) and their roles in the apoptosis of protoscoleces, recombinant Eg-BAG3 and Eg-EB1were expressed in E. coli BL21(DE3), and bioinformatic analysis, Western blotting and immunofluorescence localization were conducted to explore the molecular characteristics of Eg-BAG3 and Eg-EB1. The apoptosis of protoscoleces was induced by 10 mmol·L^-1H₂O₂ and the transcription levels of Eg-BAG3 and Eg-EB1 were detected by qRT-PCR, and their roles in the apoptosis of protoscoleces was further verified by RNA interference (RNAi). Eg-BAG3 contained the characteristic BAG domain of BAG protein family and Eg-EB1 contained the characteristic BAR domain of endophilin protein family, suggesting that Eg-BAG3 and Eg-EB1 were the typical BAG protein and endophilin protein, respectively. Immunolocalization showed that Eg-BAG3 was widely distributed in all development stages of E. granulosus,Eg-EB1 was mainly located in the tegument, suckers and rostellum of protoscoleces and germinal layer, while no positive signal was observed in adults. Protoscoleces apoptosis was successfully induced by 10 mmol·L^-1H₂O₂ and the relative transcription levels of Eg-BAG3 and Eg-EB1 significantly increased in response to H₂O₂ treatment. RNA interference (RNAi) analysis showed that the apoptosis rate of protoscoleces in the Eg-BAG3 interference group was significantly increased compared with non-interference group (P<0.05), while the Eg-EB1 interference group showed a lower apoptosis rate of protoscoleces than non-interference group (P<0.05), suggesting that Eg-BAG3 inhibited protoscoleces apoptosis induced by H₂O₂, while Eg-EB1 promoted protoscoleces apoptosis. In conclusion, Eg-BAG3 could inhibit protoscoleces apoptosis induced by oxidative stress, while Eg-EB1 promotes apoptosis, and both Eg-BAG3 and Eg-EB1 are possibly involved in regulating the formation of infertile cysts.

This study aimed to evaluate the safety and stability of the mouse-derived antimicrobial peptide CRAMP and its role in eradicating Pseudomonas aeruginosa biofilms. The hemolysis of CRAMP against rabbit red blood cells and the cytotoxicity against murine macrophage cells (RAW264.7.) were determined. The effects of temperature, proteases, metal ions, and pH on the antimicrobial activity of the CRAMP, and the stability of the CRAMP were investigated. The mature biofilm of P. aeruginosa (PAO1 strain) was constructed in the 6-well cell culture plate, and the human antimicrobial peptide LL-37 and three kinds of antibacterial drugs were used as controls. The biofilm biomass was detected by the crystal violet staining method. The number of viable bacteria in biofilms was counted, and the extracellular polysaccharide content of the biofilm was detected by the Phenol-sulfuric acid and Foline-phenol reagent method, and the morphological changes of the PAO1 biofilm were observed by the laser scanning confocal microscope (CLSM). The results showed that the hemolysis rate of CRAMP in rabbits was below 2% at the tested concentrations; The CRAMP had no cytotoxicity to RAW264.7 at 62.5-125 mg·L^-1. Temperature (25-100℃), two salt ions (Na⁺, K⁺), and pH value 5-10 do not affect the antibacterial activity of CRAMP; Pepsin, papain, and trypsin affected the antibacterial activity of CRAMP to varying degrees. In the 6-well cell culture plate, 4-fold MIC of the CRAMP extremely significantly reduced the PAO1 biofilm (decreased rate is 76.74%), and reduced the number of viable bacteria in the biofilm (reduced by 1.2 lg CFU·mL^-1), and the effect is better than that of the LL-37 and three kinds of antibacterial drugs. The extracellular polysaccharide of the CRAMP group was significantly lower than that of the blank control group and LL-37 group. CLSM results showed that:Compared with the control group, the total fluorescence intensity (PI+SYTO) of the bacteria in the CRAMP group was significantly lower than the blank control group and the LL-37 group at a 4-fold MIC concentration. Compared with the blank control group, the ratio of dead to living fluorescence intensity (PI/SYTO) in the CRAMP group and LL-37 group was significantly increased. The above results suggest that the CRAMP has low hemolysis and cytotoxicity, and it has greatstability in addition to the unstable action of protease. The CRAMP has an obvious eradication effect on the mature biofilm of PAO1, and the effect is better than LL-37, which implies that the CRAMP has a good prospect for drug development.

HEK293 cells were used as the cell model to investigate the role of human aminopeptidase N (hAPN) in the invasion of porcine deltacoronavirus (PDCoV) into human cells. The proliferation of PDCoV on HEK293 cells was firstly identified by RT-qPCR/RT-PCR. And then, hAPN knockout cell line was constructed by CRISPR/Cas9 technology and cell viability of HEK293 hAPN knockout and wild-type cells was verified by CCK-8 assay. Effect of hAPN knockout and overexpression on PDCoV replication was detected by RT-qPCR and Western blot. Meanwhile, interaction of PDCoV S protein and hAPN protein was analyzed by homology modeling and molecular docking. Results showed that PDCoV virus copies rapidly increased at 12-36 h and reached peak level at 36 h, it could propagate at least for passage 2 on HEK293 cells. There was no significant difference in cell viability between hAPN knockout cells and wild-type cells. Knockout of hAPN inhibit PDCoV replication and overexpression of hAPN enhance PDCoV replication. Homology modeling and molecular docking analysis showed S1 protein could bind hAPN domain II. Residues TYR⁹², THR⁵¹, THR⁴⁸, PHE¹⁶ and MET¹⁴of S1 protein receptor binding motif 1 (RBM1) can form hydrogen bonds with residues PHE⁴⁹⁰, GLN⁵³¹, ARG⁵²⁸ and SER⁵²⁹ of hAPN. This study indicates that hAPN plays a critical role in HEK293 cells during PDCoV infection, which provides new theoretical evidence for further studies on the mechanism of PDCoV entry into host cells and cross-species transmission.

This study was conducted to investigate the pathogenicity of four serotypes of fowl adenovirus (FAdV-4, -8a, -8b and -11) that popular in China in chicken embryos and SPF chickens. Here, 12-day-old SPF chicken embryos, 10-day-old SPF chickens were infected with FAdV-4, -8a, -8b and -11 strains, respectively, the mortality of them were calculated, and body weight of embryo were measured, then gross lesions, histopathological examination and viral load in the tissues of chicken were tested. The results showed that embryo mortality was more than 45% for FAdV-8b and -11, and embryo weight loss was the greatest for FAdV-8a and smallest for FAdV-4. Chicken mortality was only present with FAdV-4 infections (53.3%) and no chicken was dead in other groups infected with FAdV-8a, -8b and -11. Besides lesions in the liver, hydropericardium, gizzard erosions, proventricular swelling and pancreatic necrosis were characteristic of chickens infected with FAdV-4, -8a, -8b and -11, respectively, and characterized by cell necrosis in parenchymal tissues accompanied by inflammatory cell infiltration. All immune organs in infected chickens possessed lesions. Compared with lesions caused by infection with FAdV-4, serious lesions were observed in chicken infected with FAdV-8a, -8b and -11. The results showed that viral loads in pancreas of chicken infected with FAdV-8b and -11 were higher than that infected with FAdV-4, and the viral loads in heart, liver and kidney of chicken infected with FAdV-4 at 5 days post infection were higher than those at 3 and 7 days post infection, and the viral load in the organs were consistent with the degree of damage in all the chickens infected, except the chicken infected with FAdV-8a. Here, we describe for the first time that the pathogenicity of these four serotypes FAdVs in embryos do not represent their pathogenicity to chickens. More attention also should be paid to FAdV-8a, -8b and -11 infections due to their severe lesions in the embryos that of the result of vertical transmission, and in the organs of the digestive and immune system that does not result in direct mortality but retard to growth and prone to secondary infection with other pathogens.

In order to explore the role of death receptor Fas in the autophagosomes formation of rat cerebral cortex induced by cadmium (Cd), twenty-four 21-day-old male SD rats were randomly divided into 4 groups:control group, Cd group, Cd and control virus co-treated group, Cd and Fas gene silencing virus co-treated group. During the experiment, the rats in the control group drank purified water freely. Rats in the virus treatment groups were injected with corresponding virus through the tail vein at a dose of 1.4×10¹¹ vg per rat on the first day. Four weeks later, rats in the Cd-exposed groups received drinking water containing 50 mg·L^-1 Cd freely for 90 days. After the experiment, the number of autophagosomes in the cerebral cortex was observed by transmission electron microscope. The protein expression level of extracellular signal-regulated kinase 1/2 (Erk1/2), p-Erk1/2, autophagy-related protein 7 (ATG7), autophagy related gene (Beclin-1), microtubule-associated protein 1 light chain 3 (LC3) in the cerebral cortex were detected by Western blot. The expression level of LC3 was detected by immunofluorescence staining. The results showed that Cd increased the number of autophagosomes in the cerebral cortex, significantly activated Erk1/2 and up-regulated the protein expression levels of ATG7, Beclin-1 and LC3 (P<0.01). Fas gene silencing inhibited Cd-induced increase of autophagosomes, and significantly inhibited Cd-induced activation of Erk1/2 and upregulation of ATG7, Beclin-1, LC3 protein expression levels (P<0.01). The results indicated that Fas participated in Cd-induced autophagosomes formation by activating Erk1/2 in rat cerebral cortex.

This study was conducted to investigate the mechanism of the toxic effects of zearalenone (ZEA) on chicken embryo fibroblasts (DF-1). The cell viability, lactate dehydrogenase activity, Caspase-3 levels, cell apoptosis, cellular reactive oxygen species levels, mitochondrial membrane potential change and expression of endoplasmic reticulum stress (ERs) and apoptosis-related genes were detected by MTT, colorimetric assay, ELISA, Annexin V-FITC/PI staining, fluorescence microscopy and RT-qPCR, respectively. The results showed that 12.5-50.0 μg·mL^-1 ZEA significantly inhibited the proliferation of DF-1 cells (P<0.01) in a time- and dose-dependent manner. Herein 25.0 μg·mL^-1 ZEA treated cells for 24 h resulted in a significant increase in LDH and Caspase-3 levels in the supernatant (P<0.01); the levels of ROS and the number of apoptotic cells in the cells were highly significant (P<0.01); the mitochondrial membrane potential was significantly reduced (P<0.01). The mRNA expression levels of apoptosis-related genes Caspase-3 and Bax were highly significantly up-regulated (P<0.01) and that of Bcl-2 was highly significantly down-regulated (P<0.01); the mRNA expression levels of ERs-related genes GRP78, ATF6, ATF4, CHOP and PERK were highly significantly up-regulated (P<0.01). The results indicated that ZEA could exert toxic effects on chicken embryonic fibroblasts through endoplasmic reticulum stress leading to apoptosis. The results of the study provide a basis for further research on the toxic effects of ZEA on chicken cells and the means of detoxification, and have implications for the treatment of related avian diseases.

The aim of this study was to investigate the serotypes, drug sensitivity and virulence genes of Salmonella isolated from laying hens in Yunnan between July 2017 and May 2019. A total of 75 Salmonella strains were isolated from the liver tissues of sick chickens. MLST serotyping, drug sensitivity, related resistance genes and virulence genes were detected. A total of 54 strains (72.00%) and 21 strains (28.00%) were determined to be ST78 and ST92, respectively, by MLST. The resistance rate to penicillin was 100%, and the resistance rates were 26.67% to tetracycline, 26.67% to doxycycline, 22.67% to sulfamethoxazole, 18.67% to amoxicillin, 16.00% to ampicillin, 14.67% to enrofloxacin, 8.00% to streptomycin, 2.67% to ciprofloxacin, and 1.33% to gentamicin. There were seven profiles of drug resistance spectrum, with 28.00% of the strains (mainly S. Gallinarum) showing multiple resistance. The detection rates of resistance genes tetA, sul2 and blaTEM were 26.67%, 10.67% and 8.00%, respectively. The virulence genes mogA, mgtC, bcfA, araB, stn and spvC were detected in all 75 strains, while the detection rate of spvB was 89.33%. The present study showed that S. Gallinarum and S. Pullorum were the main epidemic serotypes of Salmonella in laying hens in Yunnan, and that the multiple drug resistance was predominant due to the high prevalence of drug resistance genes and virulence genes harbored in the Salmonella strains.

Ovine Aichivirus D is an emerging virus in sheep in China, the aim of this study was to design primers targeting 3D gene of ovine Aichivirus D and optimize the reaction system and conditions, a TB Green Fluorescent RT-PCR method was successfully established; the assay has characteristics of good specificity and stability, high sensitivity. Total 253 sheep fecal samples (133 non-diarrheic and 120 diarrheic) were collected from 6 sheep farms in Sichuan province from April 2020 to May 2021, this virus detection rate was 8.7%, and the farm positive rate was 66.7%(4/6). Notably, the ovine Aichivirus D positive rate for the diarrheic feces (17.5%) was significantly higher than that for non-diarrheic feces (0.75%, P<0.001), suggesting that ovine Aichivirus D may be a pathogen of sheep diarrhea. In addition, 13 complete 3D genes in 1 422 bp in length were successfully cloned from ovine Aichivirus D positive samples in this study, which shared 99.4%-100.0% nt homology with each other. Evolutionary analysis showed that these 13 3D genes together with the ovine Aichivirus D 3D gene uploaded by our previous research clustered into a large independent branch. This study provides a new molecular tool for detecting ovine Aichivirus D and basic epidemiological data of ovine Aichivirus D.

Feline herpesvirus-1 (FHV-1) is double-stranded DNA enveloped virus of Varicellovirus, is one of major causative pathogen for feline upper respiratory tract infection. Based on recombinase polymerase amplification (RPA), Cas12a trans-cleavage reaction and lateral flow dipstick (LFD), a rapid visulization method for FHV-1 detection (RPA-Cas12a-LFD) was developed and validated. RPA amplified primers and crRNA synthesized primers were designed by targeting the FHV-1 TK gene, and then validation of RPA-Cas12a-LFD reaction system, sensitivity and specificity tests, and consistensy analysis of TB Green qPCR and RPA-Cas12a-LFD for FHV-1 detection were performed respectively. The results showed that the RPA-Cas12a-LFD method could specifically detect FHV-1 without cross-reaction with other associated pathogens, with advantages of high sensitivity (detection limit was 2.35×10^-1copies·μL^-1), short detection time and visual readout. The detection rate of FHV-1 in 20 clinical samples (35%, 7/20) was higher than TB Green qPCR (25%, 5/20) and the coincidence rate of 5 positive samples was 100%. In conclusion, RPA-Cas12a-LFD method was of good specificity and ultrasensitivity for FHV-1 detection without special equipment, and could be a promising and reliable tool for rapid on-site diagnosis.

The aim of this study was to investigate the antimicrobial resistance and virulence genes of Escherichia coli isolated from diarrhea sheep in Shaanxi Province. In this study, 54 diarrhea swabs were collected from 10 sheep farms. After purification, biochemical identification and 16S rRNA analysis, a total of 50 E. coli strains were isolated. For E. coli isolates, antibiotic resistance, resistance genes, and virulence genes were tested. The results showed that 49 E. coli strains display multiple-drug resistance, more than 90% of the strains were resistant to ampicillin, florfenicol, and sulfisoxazole, and 100% (50/50) of the strains were sensitive to meropenem. In addition, 8-11 resistant accounts for 68% of the total isolated strains (34/50). All strains carry 1-6 different resistance genes. Among them, Sul1 (64%), TetA (34%), bla_CTX-M (32%) had higher carrying rates, and bla_SHV (0%) was not detected. It is noteworthy that five ESBLs-strains carry the mcr-1 gene from the isolated. The results showed that the mortality rate of mice infected with the 50 strains of E. coli was 33%-100%, virulence genes were detected in 49 of the 50 isolates, with etrA showing the highest detection rate, accounting for 80% (40/50). The results indicated that the high proportion of virulence genes and the multidrug-resistance phenomena was prevalent in sheep pathogenic E. coli. The resistance phenotypes of β-lactams were basically not correlated with the resistance genes, suggesting that there might be multiple resistance mechanisms in the E. coli strains. The virulence spectrum of isolates was complex. This study provided a scientific basis for prevention and control of the pathogenic E. coli from sheep in Shaanxi area.

The aim of this study was to investigate the incidence and treatment of canine immune thrombocytopenia (ITP), and to explore the prognostic factors. In this retrospective cohort study, 26 eligible ITP cases were collected from the Veterinary Teaching Hospital of China Agricultural University from 2018 to 2019, and the basic information, clinical manifestations, laboratory test results, treatment and prognosis of the affected dogs were recorded and analyzed. Among the medical records, the poodle account for the highest proportion (58%). Evans syndrome was significantly correlated with death in the short term (14 days) after diagnosis (P=0.02). When first admitted to the hospital, all dogs had clinical signs of bleeding. According to a new dog bleeding assessment tool (DOGiBAT), the scores of the patients in this study ranged from 3 to 10, and dogs with a score >5 were associated with death within a short period after diagnosis (P=0.03), suggesting that the bleeding score could be an indicator for the prognosis of the disease. Besides, the CRP levels in the bleeding score >5 group are higher than that in the bleeding score ≤ 5 group (P=0.01), which suggests that CRP could be used to determine the severity of ITP. This study suggests the introduction of a bleeding score tool in assessing the prognosis of ITP. Compared with a single clinical sign, the bleeding scoring tool could assess the severity of ITP with a reliable metric system.