Duck Farms Research Articles

Detection and High-Throughput Microbial Analysis of Particulate Matter in Houses and Downwind Areas of Duck Farms

Particulate matter (PM) and the microorganisms of duck houses may have negative impacts on animal and human health. During 2021-2022, PM2.5 and PM10 inside and outside the duck house were sampled with a built-in air sampler in Tai’an City, Shandong Province, and the diversity and abundance of microorganisms within the PM were analyzed by macrogenomic and absolute sequence analysis. The results showed that PM2.5 and PM10 concentrations in the house and at downwind points exceeded the short-term (24 h) guideline of the global air quality guidelines (AQG). Macrogenome sequencing showed that the microbial composition of the PM2.5 samples was dominated by bacteria (exceed 85%); a total of 1316 bacterial genera and 110 fungal genera were identified in PM2.5 samples from duck house 1 in winter, which were much higher than the results of amplicon sequencing method reported before, and relatively high levels of the pathogenic bacteria (Coccidioides immitis, etc.) and the conditionally pathogenic bacterium (Rothia nasimurium) were identified at the species level. Absolute quantitative sequencing detected conditionally pathogenic bacteria and allergens at high levels in PM10 samples: Corynebacterium (5.6×107 copies/g), Aerococcus (9.9×106 copies/g), Alternaria (3.3×106 copies/g), and Aspergillus (8.3×105 copies/g). Moreover, Corynebacterium was the highest content of PM10 in summer and PM2.5 samples in winter, and its pathogenicity and potential threat should be noted. The diversity and relative abundance of microorganisms were similar in the duck house and at the downwind point. The results showed that the microorganisms in the house environment have a greater influence on the air environment around the downwind point and may pose a public health risk to the staff and the surrounding area.

Unveiling the Prevalence and Impact of Riemerella anatipestifer in Egyptian Duck Farms: Implications for Disease Management and Vaccine Development

Unveiling the Prevalence and Impact of Riemerella anatipestifer in Egyptian Duck Farms: Implications for Disease Management and Vaccine Development

Comparison of the Clinical Manifestation of HPAI H5Nx in Different Poultry Types in the Netherlands, 2014-2022.

This study describes clinical manifestations of highly pathogenic avian influenza (HPAI) H5N1, H5N8 and H5N6 outbreaks between 2014 and 2018 and 2020 and 2022 in the Netherlands for different poultry types and age groups. Adult duck (breeder) farms and juvenile chicken (broiler and laying pullet) farms were not diagnosed before 2020. Outbreaks in ducks decreased in 2020-2022 vs. 2014-2018, but increased for meat-type poultry. Neurological, locomotor and reproductive tract signs were often observed in ducks, whereas laying- and meat-type poultry more often showed mucosal membrane and skin signs, including cyanosis and hemorrhagic conjunctiva. Juveniles (chickens and ducks) showed neurological and locomotor signs more often than adults. Diarrhea occurred more often in adult chickens and juvenile ducks. Mortality increased exponentially within four days before notification in chickens and ducks, with a more fluctuating trend in ducks and meat-type poultry than in layers. For ducks, a mortality ratio (MR) > 3, compared to the average mortality of the previous week, was reached less often than in chickens. A lower percentage of laying flocks with MR > 3 was found for 2020-2022 vs. 2014-2018, but without significant differences in clinical signs. This study provides a basis for improvements in mortality- and clinical-sign-based early warning criteria, especially for juvenile chickens and ducks.

Effects of Fresh Azolla microphylla Supplementation on Pelleted Basal Diet to Local Muscovy Duck Breed Production Performances

The study was aimed to evaluate the effect of feeding fresh Azolla microphylla on pelleted basal feed on the Local muscovy duck breed production performances. The research was done for 2 months August to September 2023, in the Muscovy duck farm, Paguyuban Petani Mandiri Kademangan, (PPMK), Blitar Regency, and feed analysis was done in the Nutrition and Animal Feed Laboratory, Faculty of Animal Science, Muhammadiyah Malang University. The research method used is experiment using a completely randomized design consisting of 3 treatments and 5 replications, each experimental unit used 4 ducks, reared and plotted randomly in the litter cage. The research variables observed were: day old duck weight, final weight, feed intake, FCR and performance index. The results of the study of the effect of supplementation 10% of fresh Azolla microphylla on the best performance index of Muscovy duck (Cairina moschata), can be apply for duck feed.

Research on duck egg recognition algorithm based on improved YOLOv4

ABSTRACT 1. The following study addressed the problem of small duck eggs as challenging to detect and identify for pick up in complex free-range duck farm environments. It introduces improvements to the YOLOv4 convolutional neural network target detection algorithm, based on the working conditions of egg-picking robots. 2. Specifically, one scale of anchor boxes was removed from the prediction network, and a duck egg labelling dataset was established to make the improved algorithm YOLOv4-ours better match the working state of egg-picking robots and enhance detection performance. 3. Through multiple comparative experiments, the YOLOv4-ours object detection algorithm exhibited superior overall performance, achieving a precision of 98.85%, recall of 96.67%, and an average precision of 98.60% and F1 score increased to 97%. Compared to the original YOLOv4 model, these improvements represented increases of 1.89%, 3.41%, 1.32%, and 1.04%, respectively. Furthermore, detection time was reduced from 0.26 seconds per image to 0.20 seconds. 4. The enhanced model accurately detected duck eggs in free-range duck housing, effectively meeting the real-time egg identification and picking requirements.

Strain typing and antimicrobial susceptibility of Salmonella enterica Albany isolates from duck farms in South Korea

Salmonella enterica is distributed worldwide and is a common cause of bacterial food poisoning in humans and a serious public health problem. Although duck meat consumption has recently increased in Korea, studies on the epidemiological relationship between S. enterica contamination in duck farms are scarce. Salmonella enterica serovar Albany isolates recovered from duck farms were analyzed using two typing methods — IR Biotyper® (IRBT) and multilocus variable-number tandem repeat analysis (MLVA). The clustering results were compared with the epidemiological survey findings and the antimicrobial resistance profiles. From April 2019 to October 2020, 20 individual feces per farm from 5–6-week-old ducks were collected repeatedly from 105 duck farms. Salmonella spp. isolated from duck feces were identified using PCR and multilocus sequence typing to investigate the prevalence and distribution of the Salmonella serovars. The prevalence of S. enterica was 19%, and S. enterica Albany was the predominantly recovered isolate. The S. enterica Albany isolates underwent antimicrobial susceptibility testing to determine the minimum inhibitory concentration. MLVA and IRBT methods established relatedness and diversity among the S. enterica Albany isolates. Multidrug-resistant S. enterica Albany was distributed in all the farms. Antimicrobial resistance profiles reflected the duck farm characteristics and isolates recovered from the same farm showed an identical profile. Isolates repeatedly recovered from the same farm also showed identical IRBT clusters and MLVA groups. These findings suggest that the isolates remained on the duck farm and re-infected new duck flocks. Thus, proper cleaning and disinfection is required before the farms are repopulated.

Analisis Kelayakan Ekonomi dan Risiko Pendapatan Usaha Peternakan Itik Petelur di Desa Kebonsari Kecamatan Candi Kabupaten Sidoarjo

The research aims to 1) Identify the state of the laying duck farm business 2) Analyze the economic feasibility of laying duck farming 3) Analyze the income risk of laying duck farming. The research location was selected using a purposive method. The research was conducted using quantitative methods with a descriptive approach. Sample determination was carried out by the saturated sampling method with a population of 16 laying duck farmers, and the entire population was sampled. The results of the research that has been carried out with an average livestock land area of 1271.9 m2 get the results of economic feasibility with a value of R / C Ratio of 1.28, B / C Ratio of 0.28, BEP Production 16,341, and BEP Price of Rp 1,963. The research conducted states that the business is said to be economically feasible and has a low-risk value and has value for further development.

One-Health Challenge in H9N2 Avian Influenza: Novel Human-Avian Reassortment Virus in Guangdong Province, China

China is one of the highest producers of poultry meat output in the world, with a large scale of chicken rearing. Statistically analyzed H9N2-subtype avian influenza viruses (AIVs) have become the dominant subtype in China’s live poultry market, with the highest detection rate. Although H9N2 AIV is of low pathogenicity and tends not to cause serious disease and high mortality in poultry, it poses a great challenge to the domestic poultry farming industry by causing a decrease in appetite, a decline in egg production, and deaths caused by mixed infections with another pathogenic microorganism. Moreover, novel influenza viruses (H7N9 and H3N8) infecting humans have emerged in China, and the H9N2 AIV provides all or part of the internal genes to the new recombinant viruses, posing a potential threat to public health and safety and human health. In this research, six H9N2 AIVs were isolated from feces or oropharyngeal swabs collected from live poultry markets and duck farms in Zhanjiang. After epidemiological investigations, phylogenetic analyses, and molecular characterization, we found that the ZJ81 strain was a chicken–human–mink recombinant virus, the ML3 strain was a chicken-human recombinant virus, and all six virus strains of the virus had a bias for the human receptor-binding site and a mutation that could cause an increase in virulence in mice. Therefore, surveillance and control of H9N2 AIV should be strengthened to provide data support for cross-species transmission of H9N2 AIV.

HISTOMORPHOMETRY OF SMALL INTESTINE OF BALI DUCKS AT DIFFERENT AGES

Bali ducks are one of the local poultry breeds that have high potential as producers of meat and eggs. The existence of this Balinese duck is spread evenly in rural areas in Bali. This study aims to histomorphometry of the small intestine of Bali ducks at different ages. In this study, 18 male Bali ducks were used as small intestine samples at 1 month, 3 months and 5 months. Bali ducks were obtained from a duck farm in Mengwi District, Badung Regency, Bali Province. Sampling of the small intestine was carried out in three parts, namely the duodenum, jejunum and ileum, then the organs were fixed with NBF 10% which was then made into histological preparations with HE staining. The research results are presented in a quantitative descriptive form. The results showed that the histological structure of the small intestine, namely the duodenum, jejunum and ileum, is composed of four layers, namely the tunica mucosa, tunica submucosa, tunica muscularis and the outermost is tunica serosa. The histomorphometric results, namely the total thickness of the layers that make up the small intestine of Bali ducks aged 1, 3, and 5 months respectively were 180.39 ± 29.59µm; 170.35±32.91µm; 302.09±78.94µm. It can be concluded that the histomorphometry of the small intestine of Bali ducks in ducks aged 1, 3, and 5 months has differences of thickness.

Epidemiological investigation and β-lactam antibiotic resistance of Riemerella anatipestifer isolates with waterfowl origination in Anhui Province, China

Riemerella anatipestifer (R. anatipestifer) is a highly pathogenic and complex serotypes waterfowl pathogen with inherent resistance to multiple antibiotics. This study was aimed to investigate the antibiotic resistance characteristics and genomic features of R. anatipestifer isolates in Anhui Province, China in 2023. A total of 287 cases were analysed from duck farms and goose farms, and the R. anatipestifer isolates were subjected to drug resistance tests for 30 antimicrobials. Whole genome sequencing (WGS) and bioinformatics analysis were performed on the bacterial genomes, targeting the β-lactam resistance genes. The results showed that a total of 74 isolates of R. anatipestifer were isolated from 287 cases, with a prevalence of 25.8%. The antimicrobial susceptibility testing (AST) revealed that all the 74 isolates were resistant to multiple drugs, ranging from 13 to 26 kinds of drugs. Notably, these isolates showed significant resistance to aminoglycosides and macrolides, which are also commonly used in clinical practices. Data revealed the presence of several β-lactamase-related genes among the isolates, including a novel blaRASA-1 variant (16.2%), the class A extended-spectrum β-lactamase blaRAA-1 (12.2%), and a blaOXA-209 variant (98.6%). Functional analysis of the variants blaRASA-1 and blaOXA-209 showed that the blaRASA-1 variant exhibited activity against various β-lactam antibiotics while their occurrence in R. anatipestifer were not common. The blaOXA-209 variant, on the other hand, did not perform any β-lactam antibiotic resistance. Furthermore, we observed that blaRAA-1 could undergo horizontal transmission among different bacteria via the insertion sequence IS982. In conclusion, this study delves into the high prevalence of R. anatipestifer infection in waterfowl in Anhui, China. The isolated strains exhibit severe drug resistance issues, closely associated with the prevalence of antibiotic resistance genes (ARG). Additionally, our research investigates the β-lactam antibiotic resistance mechanism in R. anatipestifer.

Distribution of antibiotic resistance genes and their pathogen hosts in duck farm environments in south-east coastal China

Livestock farms are major reservoirs of antibiotic resistance genes (ARGs) that are discharged into the environment. However, the abundance, diversity, and transmission of ARGs in duck farms and its impact on surrounding environments remain to be further explored. Therefore, the characteristics of ARGs and their bacterial hosts from duck farms and surrounding environment were investigated by using metagenomic sequencing. Eighteen ARG types which consist of 823 subtypes were identified and the majority conferred resistance to multidrug, tetracyclines, aminoglycosides, chloramphenicols, MLS, and sulfonamides. The floR gene was the most abundant subtype, followed by sul1, tetM, sul2, and tetL. ARG abundance in fecal sample was significantly higher than soil and water sample. Our results also lead to a hypothesis that Shandong province have been the most contaminated by ARGs from duck farm compared with other four provinces. PcoA results showed that the composition of ARG subtypes in water and soil samples was similar, but there were significant differences between water and feces samples. However, the composition of ARG subtypes were similar between samples from five provinces. Bacterial hosts of ARG subtypes were taxonomically assigned to eight phyla that were dominated by the Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria. In addition, some human bacterial pathogens could be enriched in duck feces, including Enterococcus faecium, Acinetobacter baumannii, and Staphylococcus aureus, and even serve as the carrier of ARGs. The combined results indicate that a comprehensive overview of the diversity and abundance of ARGs, and strong association between ARGs and bacterial community shift proposed, and benefit effective measures to improve safety of antibiotics use in livestock and poultry farming.Key points• ARG distribution was widespread in the duck farms and surroundings environment• ARG abundance on the duck farms was significantly higher than in soil and water• Human bacterial pathogens may serve as the vectors for ARGs

Epidemiological investigation of fowl adenovirus (FAdV) infections in ducks and geese in Shandong Province, China

ABSTRACT Outbreaks of fowl adenoviruses (FAdVs) infection with the main clinical signs of hepatitis-hydropericardium-syndrome or inclusion body hepatitis have been frequently reported in ducks and geese in recent years, causing economic losses for the Chinese waterfowl industry. This study investigated 792 samples (391 fattening ducks, 192 breeder ducks and 209 fattening geese) of suspected FAdV-infected waterfowl from 38 farms (21 fattening duck farms, nine breeder duck farms and eight fattening geese farms) in Shandong Province between 2019 and 2022. The results showed a 60.23% infection rate for FAdVs (477/792), while the infection rate for breeder ducks was almost the same as that for fattening geese (55.73% vs. 54.55%). Notably, co-infection with avian influenza virus H9N2 (H9N2), Tembusu virus (TMUV), duck hepatitis virus (DHV), duck circovirus (DuCV), goose astrovirus (GAstV) and duck parvovirus (DPV)/goose parvovirus (GPV) was common among the 477 FAdVs positive cases. Phylogenetic analysis of complete hexon genes of 22 FAdV strains in Shandong Province showed the presence of four species (FAdV-A, C, D, E) and five serotypes (FAdV-1, 4, 8a, 8b, 11). These findings provide the first data on the prevalence and co-infection status of FAdVs in Shandong Province and can be used as a basis for FAdV prevention in the field. RESEARCH HIGHLIGHTS Samples of suspected FAdV-infected waterfowl from farms in Shandong Province were collected from 2019 to 2022. Single infections with FAdV were less frequent than mixed infections. 477 out of 792 samples (60.23%) tested positive for FAdV nucleic acids. Detection rate of FAdV was 65.47% in fattening duck farms, 55.73% in breeder duck farms and 54.55% in fattening geese farms.

Strategi Pemasaran Syariah Pada Wirausaha Ternak Bebek

The majority of Indonesians live off livestock. Due to increasing demand, some households in Indonesia have established layer duck farms and broiler duck farms. This is one of the main sectors to fulfill the needs of the Indonesian population. The purpose of this study were (1) to determine the level of welfare for duck farmers in Sumberpakem village, Sumberjambe sub-district, (2) to determine the effect of sharia marketing on increasing consumer demand in Sumberpakem village, Sumberjambe sub-district. This research uses a descriptive qualitative approach to explain sharia marketing strategies in duck entrepreneurship. Observations, interviews, and literature studies were the primary and secondary data sources. Data collection techniques include interviews and observations.The results of this study, the authors obtained the conclusion that sharia marketing strategies in broiler duck entrepreneurs can improve welfare for duck farmers. With sharia marketing can also increase the demand for the number of consumers

A preliminary study on short- and medium-chain chlorinated paraffins in duck farms: Concentrations, distribution, and dietary exposure risks

Chlorinated paraffins (CPs) in poultry feed and the farm environment might bioaccumulate in poultry eggs. Unlike chickens, which are mostly raised in cages, ducks are commonly raised free range. This would expose ducks to CPs in the environment. However, information on the presence of CPs on duck farms is scarce. In the present study, samples of duck eggs, duck feathers, poultry feed, and soil were collected from 25 duck farms in South China. Forty-eight congener groups of short- and medium-chain CPs (SCCPs and MCCPs) were detected in the samples. Interestingly, relatively high concentrations of SCCPs and MCCPs were found in the duck feathers. The median concentrations of SCCPs and MCCPs in the duck eggs, feathers, feed and soil were: 46 and 18 ng/g wet weight, 2460 and 992 ng/g, 103 and 47 ng/g, and 24 and 10 ng/g dry weight, respectively. The dominant groups of SCCPs and MCCPs were C10Cl6–7 and C14Cl7–8, respectively. The close relationship between duck feathers and poultry feed indicated that the duck feathers might act as a bioindicator for the exposure of ducks to CPs. The margin of exposure approach was used to assess the health risk, with the results showing that the consumption of duck eggs posed a low risk to different age groups from exposure to SCCPs and MCCPs.

The ISVsa3-ORF2-abh-tet(X4) circular intermediate-mediated transmission of tigecycline resistance in Escherichia coli isolates from duck farms.

Tigecycline is a last-resort drug used to treat serious infections caused by multidrug-resistant bacteria. tet(X4) is a recently discovered plasmid-mediated tigecycline resistance gene that confers high-level resistance to tigecycline and other tetracyclines. Since the first discovery of tet(X4) in 2019, it has spread rapidly worldwide, and as a consequence, tigecycline has become increasingly ineffective in the clinical treatment of multidrug-resistant infections. In this study, we identified and analyzed tet(X4)-positive Escherichia coli isolates from duck farms in Hunan Province, China. In total, 976 samples were collected from nine duck farms. Antimicrobial susceptibility testing and whole-genome sequencing (WGS) were performed to establish the phenotypes and genotypes of tet(X4)-positive isolates. In addition, the genomic characteristics and transferability of tet(X4) were determined based on bioinformatics analysis and conjugation. We accordingly detected an E. coli strain harboring tet(X4) and seven other resistance genes in duck feces. Multi-locus sequence typing analysis revealed that this isolate belonged to a new clone, and subsequent genetic analysis indicated that tet(X4) was carried in a 4608-bp circular intermediate, flanked by ISVsa3-ORF2-abh elements. Moreover, it exhibited transferability to E. coli C600 with a frequency of 10-5. The detection of tet(X4)-harboring E, coli strains on duck farms enhances our understanding of tigecycline resistance dynamics. The transferable nature of the circular intermediate of tet(X4) contributing to the spread of tigecycline resistance genes poses a substantial threat to healthcare. Consequently, vigilant monitoring and proactive measures are necessary to prevent their spread.

Isolation and characterization of duck viral enteritis (Duck plague) virus from ducks in field outbreaks in Bangladesh

Duck viral enteritis (DVE) also known as duck plague (DP) is a fatal viral disease of ducks globally that causes huge economic losses in the duck industries. The main objectives of the current study were: the isolation of the circulating duck viral enteritis virus (DVEV) from clinical specimens of field outbreaks, molecular identification of the virus and genetic characterization of DVEVThe natural outbreaks of duck plague (DP) were reported between February and June 2018 on three commercial duck farms located at Netrokona, Mymensingh and Nilphamari districts of Bangladesh. A total of 42 dead ducks were collected from the three farms. Postmortem examination of dead ducks was carried out and gross lesions of the visceral organs were recorded.Liver and spleen samples were collected aseptically and 10% viral inoculum was prepared from liver and spleen. Isolation of DVEV was done by injecting viral inoculum into 9-13 days old embryonated duck eggs through the chorioallantoic membrane (CAM) route.Molecular detection of DVEV in liver, spleen and CAM homogenate was performed by PCR targeting 446 bp fragment of DNA polymerase gene of DVEV. Phylogenetic analysis was carried out by comparing the amino acid sequence of field isolatesof DVEV with the amino acid sequence of global isolates of DVEV deposited in the GenBank. Enlargement of the liver and spleen, abdominal haemorrhage, and annular rings of the trachea were seen in the affected ducks which were characteristics gross lesions in DVE.18of 42 samples (42.85%) were found positive for DVEV by PCR assays. Embryos of duck experimentally inoculated with DVEV were found dead at 3-5 days post infection.Degenerated blood vessels of the CAM, dwarfism of the embryos was observed. The phylogenetic study revealed that the DVEV isolates causing disease outbreak in ducks in the current study were 100% similar to the isolates of DVEV thatpreviously reported from Bangladesh, Vietnam and China.

Ecological drivers for poultry farms predisposed to highly pathogenic avian influenza virus infection during the initial phase of the six outbreaks between 2010-2021: a nationwide study in South Korea.

Highly pathogenic avian influenza (HPAI) has caused substantial economic losses worldwide. An understanding of the environmental drivers that contribute to spillover transmission from wild birds to poultry farms is important for predicting areas at risk of introduction and developing risk-based surveillance strategies. We conducted an epidemiological study using data from six HPAI outbreak events in South Korea. An aggregate-level study design was implemented using third-level administrative units in South Korea. Only regions with high natural reservoir suitability were included. The incidence of HPAI at chicken and duck farms during the initial phase (30 and 45 days after the first case) of each outbreak event was used as the outcome variable, assuming that cross-species transmission from wild birds was the dominant exposure leading to infection. Candidate environmental drivers were meteorological factors, including temperature, precipitation, humidity, and altitude, as well as the proportion of protected area, farm density, deforestation level, and predator species richness. Logistic regression models were implemented; conditional autoregression models were used in cases of spatial autocorrelation of residuals. Lower temperature, higher farm density, and lower predator species richness were significantly associated with a higher risk of HPAI infection on chicken farms. Lower temperature, higher proportion of protected area, and lower predator species richness were significantly associated with a higher risk of HPAI infection on duck farms. The predicted dominant transmission routes on chicken and duck farms were horizontal and spillover, respectively. These results reveal a potential protective effect of predator species richness against HPAI outbreaks. Further studies are required to confirm a causal relationship.

Complete genome sequence of Japanese encephalitis virus strain SDWF-2021 isolated from a Culex mosquito pool from a duck farm.

We report here the complete genome sequence of Japanese encephalitis virus (JEV) strain SDWF-2021, isolated from a Culex mosquito pool in a duck farm located in Shandong, China. The isolated JEV genetically belong to genotype I, which is the dominant genotype circulation in China.

Exploring the potential of natural feed additives from herbs as an alternative to antibiotic growth promoters for Mojosari layer duck (Anas javanica) farming: in-silico and in-vivo studies

Using synthetic feed additive, such as antibiotic growth promoters (AGPs), is common in Mojosari layer duck (Anas javanica) farms. Their purpose is to enhance growth and productivity. However, the indiscriminate use of AGPs has been associated with the emergence of bacterial resistance. This leads to lingering effects and potential health hazards for poultry and consumers. In light of these concerns, natural herb feed additives have emerged as an alternative strategy to AGPs in poultry feed. The active compounds in natural feed additives can improve feed efficiency and enhance production performance, resulting in higher-quality poultry products, especially eggs. However, it is known that the active compounds in phytobiotics derived from herbs contain anti-nutrients that can affect productivity and alpha-amylase in poultry. This study was aimed to investigate the interconnection between active compounds in phytobiotics and alpha-amylase using in-silico methods and verify the findings with field data using in-vivo methods. Alpha-Amylase is a vital enzyme that catalyzes the hydrolysis of the glycosidic bonds present in glycogen, resulting in the formation of maltose, a water-soluble disaccharide. Based on the results of docking involving nine phytobiotic compounds and their interaction with glycogen, it was observed that andrographidine E showed a binding affinity of 8.8 kcal/mol. Furthermore, these compounds form conventional hydrogen bonds, facilitated the formation of stable bonds between proteins and compounds. In particular, the interacting amino acids did not exhibit unfavourable bonds. Therefore, andrographidine E was more stable compared to other compounds. Nonetheless, the results show that several compounds have weaker binding affinity than the enzyme's binding to glycogen. However, the hydrophobic binding types of these compounds did not seem to impact the performance of the alpha-amylase enzyme, as demonstrated by in vivo data.

Mobile genetic elements facilitate the transmission of antibiotic resistance genes in multidrug-resistant Enterobacteriaceae from duck farms

Multidrug-resistant (MDR) Enterobacteriaceae critically threaten duck farming and public health. The phenotypes, genotypes, and associated mobile genetic elements (MGEs) of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province, China, were investigated. A total of 215 isolates were identified as Escherichia coli (64.65 %), Klebsiella pneumoniae (12.09 %), Proteus mirabilis (10.23 %), Salmonella (8.84 %), and Enterobacter cloacae (4.19 %). Meanwhile, all isolates were resistant to at least two antibiotics. Most isolates carried tet(A) (85.12 %), blaTEM (78.60 %) and sul1 (67.44 %) resistance genes. Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons. A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004. This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene. MGEs, especially plasmids, are the primary antibiotic resistance gene (ARG) transmission route in duck farms. These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety.