Enterotoxigenic Escherichia coli (ETEC)-induced neonatal calf diarrhea (NCD) causes significant economic losses to the cattle industry; therefore, understanding its antibiotic resistance is crucial for developing targeted prevention and treatment strategies. However, reports on antibiotic resistance in bovine ETEC are currently limited. This study conducted whole-genome sequencing (WGS) and antimicrobial susceptibility testing on ETEC F5- and F5-F41-positive strains isolated from neonatal calf diarrhea samples in Inner Mongolia, China. The results showed that both ETEC F5- and ETEC F5-F41-positive strains are multidrug-resistant, containing ceftriaxone (CRO), ceftazidime (CAZ)) and ciprofloxacin (CIP), which are listed as the highest priority critically important antimicrobial (HP-CIAs) by the World Health Organization (WHO). Combined analysis using the Comprehensive Antibiotic Resistance Database (CARD) and ResFinder 4.1 predictive analysis revealed that the chromosomes and plasmids of the 2 ETEC-positive strains contained 11 classes of antibiotic resistance genes, with the top 3 categories in terms of the number of resistance genes being aminoglycosides, β-lactamases, and chloramphenicols. In addition, various bacterial efflux pumps, including RND, MFS, SMR, and the ABC efflux pump family, were detected. A total of 74 antimicrobial resistance genes were identified in the 2 strains, belonging to 5 categories of drug resistance mechanisms; the antimicrobial resistance phenotype was consistent with the genotype. This study provides a reference for the prevention and treatment of diarrhea caused by ETEC.

Salmonella poses a significant health threat to both humans and animals owing to the emergence of antimicrobial-resistant strains. There are no studies on the incidence patterns of salmonellosis and multidrug-resistant Salmonella strains in Inner Mongolia, China's milk and beef-producing hotspot. Farms in Inner Mongolia, China, were randomly selected, and rectal swabs (600) and milk samples (757) were collected for isolation and identification of Salmonella, and antimicrobial resistance was assessed according to CLSI and NARMS guidelines. Twenty-one resistance genes from seven classes of antibiotics were selected for detection using polymerase chain reaction (PCR), and Salmonella-NMGS9 was selected for whole genome sequencing and drug resistance gene prediction analysis. Salmonella was found in 24 (85.71

为了阐明内蒙古部分地区致犊牛腹泻产肠毒素大肠杆菌的流行情况,该研究以内蒙古自治区乌兰察布和鄂尔多斯地区部分牛场腹泻病例为研究对象,采集患病犊牛样本,采用PCR方法检测产肠毒素大肠杆菌(Entero-toxigenic E.coli,ETEC)的ST和LT基因进行ETEC菌株鉴定.研究结果显示,乌兰察布地区ETEC检测总阳性率为11.71％,鄂尔多斯地区ETEC总阳性率为9.44％,其中0～2月龄阳性率为21.49％,2～6月龄阳性率为5％,6～18月龄阳性率为0.由此可知,乌兰察布地区ETEC检测总阳性率高于鄂尔多斯地区,两个地区ETEC的流行情况和感染情况均以0～2月龄犊牛为主,为进一步开展犊牛腹泻疾病的防控提供了依据.

牛副结核病是在世界范围内流行的、以牛肉芽肿性肠炎和进行性消瘦为主要特征的传染病,给畜牧生产造成了严重危害和巨大经济损失.牛副结核病由副结核分枝杆菌引起,致病机制复杂,传播方式多种多样,病原体难以分离培养.对牛副结核病的致病机制及其致病菌躲避免疫系统方式进行综述,提出病料去污处理方法研究能更好地为分离培养和研究副结核分枝杆菌提供帮助,以期为牛副结核病的预防诊断和治疗提供理论指导.

Bovine diarrhea is a multi-factorial disease and remains one of the biggest health problems in animal husbandry. The endemic trends of the main pathogens responsible for bovine diarrhea in Inner Mongolia have not been analyzed systematically before. Therefore, the purpose of this study was to estimate the prevalence of bovine diarrhea pathogens found in the scattered households of Inner Mongolia in China. Additionally, we assessed for differences in the prevalence of infection based on age and region, as well as determined local prevalence rates and the rates of mixed infections. Using a two stage random sampling strategy, 3,050 serum samples were collected from 72 bovine herds in 11 leagues and cities in Inner Mongolia, and the positive rates of BVDV, BRV, BCoV, K99, and Mycobacterium paratuberculosis (M. paratuberculosis) antibodies in the samples were detected by ELISA to determine the epidemic trends and epidemic differences of the five pathogens in Inner Mongolia. The positive rates of antibodies based on serum samples were: BVDV, 18.79% (95% CI [17.44-20.22]); BRV, 12.39% (95% CI [11.27-13.61]); BCoV, 12.82% (95% CI [11.68-14.05]); K99, 13.80% (95% CI [12.62-15.07]); and M. paratuberculosis , 10.79% (95% CI [9.74-11.94]). The prevalence rates of BRV, BCoV and K99 at 0-2 months were significantly different from that at 2-6 months, 6-18 months and adult cattle (P < 0.05). The prevalence of BVDV and M. paratuberculosis was the highest in adult cattle, which was significantly different from that in other age groups (P < 0.05). Furthermore, obvious regional epidemiological differences among the five diseases were observed. There was a mixed infection of BRV+BCoV in each age stage, the highest mixed infection being BVDV+BRV+K99 at 0-2 months of age. Our results showed that the cattle of scattered households in the Inner Mongolia of China were endemicly infected with several important cattle pathogens. Most of the pathogens studied occurred between 0-2 months of age and were mixed infections, which greatly influences the health of the cattle and leads to economic loss. These findings are of practical significance for the future prevention and control of bovine diarrhea in the Inner Mongolia or other regions of China.

为了解内蒙古巴彦淖尔地区规模养殖场由产肠毒素大肠杆菌(ETEC)F5菌毛引起的腹泻流行情况,采集巴彦淖尔市规模化养牛场284份血样和300份粪样,采用ELISA和PCR方法进行了产肠毒素大肠杆菌F5抗体及分子流行病学调查,结果显示:产肠毒素大肠杆菌F5抗体总阳性率为6.34％,抗原总阳性率为27.00％;在采集的样品中,0～2月龄犊牛的抗原阳性率最高,为20.67％,抗体阳性率为4.23％,表明巴彦淖尔地区ETEC F5在0～2月龄犊牛中流行,应进一步开展犊牛腹泻疾病的防控.

从内蒙古自治区通辽市部分规模化养牛场采集粪样350份、血样325份,分别采用RT-PCR和ELISA方法进行牛冠状病毒(Bovine coronavirus,BCoV)的分子流行病学调查,了解内蒙古自治区通辽市规模化养殖场牛冠状病毒的流行状况,以期为通辽地区养牛场牛冠状病毒病的防控提供参考.结果显示:抗原总阳性率为22.86％,抗体总阳性率为7.69％.在采集的样品中,0～2月龄犊牛的抗原阳性率最高,达57.50％,抗体阳性率最高,达19.00％,表明通辽地区牛冠状病毒流行率较高,及时采取科学有效的防控措施是很有必要的.

本研究采集内蒙古自治区呼和浩特市某牛场腹泻犊牛粪样,对其进行牛轮状病毒分离鉴定和遗传进化分析.将RT-PCR检测阳性的腹泻粪样接种于MA104细胞,盲传4代后分离得到一株出现明显细胞病变的毒株,命名为HSX-21;对分离的毒株进行VP7多重半套式PCR鉴定基因型,将分离毒株测序得到的VP6、VP7和VP4基因进行遗传进化分析.结果表明分离到的毒株基因型为A群G6P[1]型,VP6基因与美国分离株NCDV同源性高达99.7％,VP7基因与英国分离株RF同源性高达99.9％;VP4基因与中国分离株NMG17044同源性高达98.8％.通过对牛轮状病毒的分离和基因型的确定,可为有效的防控本地区牛轮状病毒感染提供前期基础和理论依据.

Bovine diarrhea is a multi-factorial disease, and remains one of the most serious health problems in cattle husbandry. However, the endemic trends of the main pathogens responsible for bovine diarrhea have not been analyzed before, therefore, the purpose of this study was to estimate the prevalence of bovine diarrhea pathogens in the large-scale cattle farms of Inner Mongolia in China, we assessed the differences in the prevalence of infection based on age and area, as well as determined local prevalence rates and the rates of mixed infections. Using stratified random sampling strategy, cattle were divided into four age stages (0-2 months, 3-6 months, 7-18 months and ＞18 months), 2,216 serum samples were collected from 38 cattle herds in 12 leagues and cities in Inner Mongolia of China. Positive rates of Bovine Viral Diarrhoea Virus (BVDV), Bovine Rotavirus (BRV), Bovine Coronavirus (BCoV), Escherichia coli K99 (E.coli K99), and M. paratuberculosis (Mptb) antibodies were detected in the samples by ELISA to determine the epidemic trends and differences of the five pathogens in Inner Mongolia. The positive rate of BVDV vaccine higher than 90% in each age category of cattle, and the prevalence rates of BRV and Mptb in other ages significantly higher than ＞18 months (P <0.05). Except BVDV, the prevalence of BCoV was the highest in 0-2 months old (74.88%), the highest positive rate in ＞18 months old is BRV (63.31%), the infection of viral pathogens were serious in Inner Mongolia. With the highest mixed infection (33.74%) being BRV and BCoV in the category of 0-2 months, and there was a mixed infection of BRV and BCoV at four age stages, Only double and triple infections were detected in cattle aged 2-6 months and 6-18 months, quadruple infections were detected in cattle aged 0-2 months and ＞18 months. Furthermore, obvious regional epidemiological differences among the five pathogens were observed, 5 pathogens were detected in 11 regions, Hulun Buir city was seriously infected with bacterial pathogens, only antibodies to viral pathogens were detected in Ulanqab city. All the above detected pathogens can trigger high mortality and poor prognosis in cattle. This study is the first to report the prevalence and characteristics of the main pathogens of bovine diarrhea in large-scale cattle farms in Inner Mongolia, China, which has practical significance for the future prevention and control of bovine diarrhea and reduce economic losses in cattle farming.

Diarrhea caused by different pathogens can lead to changes in the structural characteristics of intestinal flora of calves. In order to study the diversity of intestinal flora, 38 fresh faecal samples were collected from three large-scale cattle farms in western Inner Mongolia, including 30 diarrhoea faecal samples and 8 healthy faecal samples. The diarrhoea-associated pathogens were tested by PCR and then the samples were divided into three groups, the healthy group（HC）, the bovine rotavirus（BRV）-infected diarrhoea group（DC＿a） and the Escherichia-Shigella infection diarrhoea group（DC＿b）. Total DNA was extracted and the highly variable V3-V4 region of the bacterial 16S rDNA gene was amplified by PCR using universal primers, sequenced by the Illumina NovaSeq platform and the sequencing results were analyzed by bioinformatics. The results of α diversity index showed that there was a significant difference in intestinal microbial diversity between diarrhea and healthy calves, and the α diversity index of DC＿b group was significantly lower than that of the other two groups（P＜0.05）. At phyla level, the dominant phyla in the three groups were Firmicutes, Bacteroidetes, Actinobacteria and Proteobacteria, but their relative abundance were significantly different. In DC＿b group, Firmicutes were significantly decreased（P＜0.05） and Actinobacteria were significantly increased（P＜0.05）. At the genus level, the dominant genera and relative abundance of the three groups were different. PICRUSt2 function prediction analysis showed that compared with HC group, DC＿a group significantly decreased mannose-degradation, galactose degradation, sugar and vitamin biosynthesis and other related metabolic pathways. DC＿b was significantly enriched in hexitol degradation and L-tryptophan biosynthesis. This study showed that the difference between healthy calves and diarrhoeic calves was significant（P＜0.05） in the intestinal flora of the phylum Firmicutes and Actinomycetes; Not only the pathogenic bacteria in the phylum Aspergillus can cause diarrhoea in calves but also lead to an inflammatory response in the intestine; Family Rumexcoccus has multiple functions and it is difficult to infer functional differences between genera from amplicon sequencing data; It can also be concluded that diarrhoea is closely related to energy and nutrient metabolism and amino acid metabolism.

To study the role of orexin A in the reproductive regulation of Mongolian sheep, ovine ovarian granulosa cells were cultured in vitro. The cells were divided into groups after luteinization, the experimental group was given orexin A and the transcriptome was sequenced together with that of the control group. The different genes related to reproduction were screened out. qRT-PCR, western blot and enzyme-linked immunosorbent assay (ELISA) were used to verify the selected genes and detect the effect on progesterone secretion. In total, 123 differentially expressed genes were obtained by sequencing. Six genes with high expression related to reproduction (PRRT2, ABCG1, SOX4, TBX3, ID1 and ATP8) were screened. The results of qRT-PCR were consistent with those of sequencing; western blot and ELISA were used to verify the protein levels of steroidogenic acute regulatory protein (StAR) and its related PRRT2 and ABCG1, and to detect their effect on progesterone secretion. Validation results were consistent with those of qRT-PCR and sequencing. The experimental group was given orexin A and compared with the control group. Expression of PRRT2 protein was significantly increased (P < 0.05), ABCG1 protein expression was significantly decreased (P < 0.05), StAR expression was significantly increased (P < 0.05), and progesterone secretion was significantly increased (P < 0.05). The results showed that orexin A promoted the expression of StAR by upregulating PRRT2 and downregulating ABCG1, therefore affecting secretion of progesterone. Gene expression characteristics of orexin A affecting progesterone secretion were preliminarily explored; this study provides a theoretical basis for further study on signalling pathways and reproductive regulation in Mongolian sheep.

食欲素A(orexin A)作为一种重要的神经肽类激素,通过与G蛋白耦联受体结合影响生殖功能.为了研究orexin A对绵羊黄体化颗粒细胞基因表达的影响及其信号网络,培养绵羊卵巢黄体化颗粒细胞进行鉴定,提取黄体化颗粒细胞组和添加Orexin A的黄体化颗粒细胞组的RNA,采用lllumina测序技术进行测序,利用生物信息学方法对转录组数据进行分析,在测序数据质量控制的基础上,对差异表达的基因进行筛选、功能注释和富集分析.结果 表明,黄体化颗粒细胞组的孕酮分泌量显著高于未黄体化颗粒细胞组;转录组测序共获得了50个差异基因,其中上调表达20个,下调30个;发现多个与细胞周期调控、繁殖及代谢相关的高表达基因,如PRRT2、ID1、RRM2、ATP6、ATP8、KIRREL、SOX4、TBX3等基因,结合GO分析和KEGG通路分析表明,差异基因主要参与代谢途径、氧化磷酸化、癌症信号通路、GnRH信号通路、cGMP PKG信号通路、Rap1信号通路、Wnt信号通路以及Ca离子信号通路等.本试验为进一步阐明orexin A影响绵羊的生殖调控提供了依据.

为了探究不同剂量的黄芪多糖粉对绵羊临床用药安全性的影响,试验将40只年龄及生长状况相近的乌珠穆沁羊随机分为4组,每组10只,分别为对照组和饲料中添加不同剂量的黄芪多糖粉(400 g/t、1 200 g/t、2000 g/t)组,饲喂21 d,于给药第1 d、第14 d和停药后第7d分别采集血液样品,使用血液分析仪检测血液常规指标和血清生化指标.结果表明临床观察黄芪多糖粉各剂量组的状态与对照组相比未出现与药物毒性相关的临床症状;测定血液常规指标和血液生化及离子浓度等指标,黄芪多糖粉各剂量组与对照组结果比较分析,差异不显著.说明在饲料中添加临床用药剂量的1倍、3倍和5倍的黄芪多糖粉对绵羊的血液常规指标和血清生化指标无明显影响,黄芪多糖粉可以作为一种添加剂安全应用于绵羊的临床用药.

为探讨食欲素A (orexin A)影响绵羊卵巢颗粒细胞分泌孕酮是否受环磷酸腺苷(cAMP)及其下游环磷酸腺苷效应原件结合蛋白(CREB)的调节,体外培养绵羊卵巢颗粒细胞并进行姬姆萨染色、卵泡刺激素受体免疫荧光染色鉴定后,采用细胞免疫组化手段对CREB的存在及位置做出确定.经黄体化处理后分组添加不同浓度(10 nmol/L、100 nmol/L、1 μmol/L)的食欲素A受体阻断剂(HY-10805A)孵育2h,再添加不同浓度(10 nmol/L、58 nmol/L)的食欲素A,运用ELISA方法检测细胞内cAMP浓度的变化.在细胞培养液里添加不同浓度(100 nmol/L、1μmol/L、10 μmol/L)的CREB抑制剂(HY-101120)孵育2h,后添加相同浓度(10 nmol/L)的食欲素A,运用ELISA方法检测细胞培养上清液中孕酮的浓度.结果显示,姬姆萨染色后,可见长梭形或不规则星形卵巢颗粒细胞,细胞着色均匀,胞浆淡蓝色,细胞核深蓝色.免疫组化试验组细胞形态清晰,胞核呈黄色,胞浆无染色.添加食欲素A受体阻断剂组与对照组相比,cAMP的浓度显著降低(P＜0.01),不同浓度CREB抑制剂组与对照组相比,孕酮含量均下降,且下降趋势在其浓度为10μmol/L时达到最高(P＜0.01).结果表明,绵羊卵巢颗粒细胞中存在CREB,且浓储于细胞核,外加食欲素A可影响绵羊卵巢颗粒细胞cAMP的含量,而在阻断其下游原件CREB后,孕酮分泌明显受到影响,说明CREB对绵羊卵巢颗粒细胞的孕酮分泌有影响.