Commercial Broiler Chicken Farms Research Articles

Insights into the genomic and phenotypic characteristics of Bacillus spp. strains isolated from biofilms in broiler farms.

The characterization of surface microbiota living in biofilms within livestock buildings has been relatively unexplored, despite its potential impact on animal health. To enhance our understanding of these microbial communities, we characterized 11 spore-forming strains isolated from two commercial broiler chicken farms. Sequencing of the strains revealed them to belong to three species Bacillus velezensis, Bacillus subtilis, and Bacillus licheniformis. Genomic analysis revealed the presence of antimicrobial resistance genes and genes associated with antimicrobial secretion specific to each species. We conducted a comprehensive characterization of the biofilm formed by these strains under various conditions, and we revealed significant structural heterogeneity across the different strains. A macro-colony interaction model was employed to assess the compatibility of these strains to coexist in mixed biofilms. We identified highly competitive B. velezensis strains, which cannot coexist with other Bacillus spp. Using confocal laser scanning microscopy along with a specific dye for extracellular DNA, we uncovered the importance of extracellular DNA for the formation of B. licheniformis biofilms. Altogether, the results highlight the heterogeneity in both genome and biofilm structure among Bacillus spp. isolated from biofilms present within livestock buildings.IMPORTANCELittle is known about the microbial communities that develop on farms in direct contact with animals. Nonpathogenic strains of Bacillus velezensis, Bacillus subtilis, and Bacillus licheniformis were found in biofilm samples collected from surfaces in contact with animals. Significant genetic and phenotypic diversity was described among these Bacillus strains. The strains do not possess mobile antibiotic resistance genes in their genomes and have a strong capacity to form structured biofilms. Among these species, B. velezensis was noted for its high competitiveness compared with the other Bacillus spp. Additionally, the importance of extracellular DNA in the formation of B. licheniformis biofilms was observed. These findings provide insights for the management of these surface microbiota that can influence animal health, such as the use of competitive strains to minimize the establishment of undesirable bacteria or enzymes capable of specifically deconstructing biofilms.

Genotype classification and pathogenicity of infectious bursal disease virus circulating in vaccinated broiler chicken farms

This study investigated the genotype classification and pathogenicity of infectious bursal disease virus (IBDV) circulating in vaccinated broiler chicken farms in Egypt. A total of 150 samples were collected from 30 vaccinated commercial broiler chicken farms and pooled into 30 working samples. IBDV was tested using reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the hypervariable region of the viral protein 2 (hvVP2) and the VP1 gene 5’ extremity. Both RT-PCR fragments were sequenced from six samples, and then the obtained nucleotide sequences were analyzed. The IBDV genotypes were identified using nucleotide sequences. Five sequences of the six strains examined were classified as genotype A3B2 for the highly virulent segments A and B (vv-A/vv-B IBDV). Interestingly, this study identified and classified a novel segment-reassortant strain as the A1B2 genotype. Specifically, it involved the segment reassortment of classical virulent segment A (cv-A) with vv-B producing cv-A/vv-B reassortant IBDV. Subsequently, we compared the pathogenicity of reassortant (cv-A/vv-B) IBDV and vvIBDV strains identified in this study. Both strains developed typical IBD clinical signs, postmortem lesions, histopathology, immunohistochemistry, and lesion scores, which were more severe in vvIBDV than reassortant IBDV. In conclusion, this is the first report of the genotype classification based on both genome segments (hvVP2 and VP1) with pathogenicity of IBDV circulating in vaccinated broiler chicken farms and this pathogenicity is more severe in vvIBDV strain than a novel reassortant IBDV strain.

The characterization and correlation between the phenotypic and genotypic resistance of Campylobacter spp. isolates from commercial broilers and native chickens in the south of Thailand

ABSTRACT Chicken is a major reservoir and source of human infections from zoonotic Campylobacter. In southern Thailand, chicken is the most popular meat consumed; however, little is known about the antimicrobial resistance (AMR) of Campylobacter spp. in chicken production systems. We aimed to investigate the prevalence and characteristics of AMR in Campylobacter isolates from commercial broiler and native chicken farms in southern Thailand. A total of 286 Campylobacter isolates (adjusted prevalence: 60.3%, SE ± 0.01) were recovered, of which 268 were identified as Campylobacter jejuni and 18 as Campylobacter coli. The adjusted prevalence of resistance was highest for nalidixic acid (98.6%), followed by ciprofloxacin (97.2%), enrofloxacin (96.4%), tetracycline (74.6%), tylosin (38.3%), and erythromycin (10.6%). Commercial broilers had resistance levels 7–11% higher to quinolones and 35–47% lower to macrolides and tetracycline (all P ≤ 0.025) compared to native chickens. Genotypic resistance analyses revealed high prevalence rates (>86%) for gyrA mutant, efflux pump CmeABC, and point mutation A2075G in the 23S rRNA gene. High homogeneity was observed among isolates within study farms. Commercial broilers exhibited higher homogeneity in AMR patterns than native chickens. The best agreement was observed between tetracycline resistance and tet(O) genes (Kappa: k = 0.811, P < 0.001), while the fair agreement was found for quinolone resistance and gyrA mutant genes (k = 0.260–0.271, P < 0.001). No association was detected between macrolide resistance and point mutations in the 23S rRNA gene. These findings fill knowledge gaps on AMR in Campylobacter in Thailand, emphasizing the need for targeted AMR mitigation strategies in both commercial broilers and native chickens. RESEARCH HIGHLIGHTS High Campylobacter prevalence in chickens; C. jejuni more prevalent than C. coli. Susceptibility to macrolides but resistance to quinolones/tetracyclines in isolates. Homogeneous resistance patterns within farms; higher in broilers than in native birds. Partial association between phenotypic and genotypic resistance among isolates.

Isolation and Characterization of Fowl Adenoviruses Associated with Hydro-pericardium Syndrome from Broiler Chickens in Egypt

One of the most prominent viral diseases affecting the poultry industry is hydropericardium syndrome caused by fowl adenoviruses. Hydropericardium syndrome has recently led to significant economic losses in the Egyptian poultry sector. Many outbreaks of hydropericardium syndrome have been documented across the country in the last few years. This research examined the epidemiology and molecular characterization of fowl adenoviruses in broiler chickens in Egypt. Samples were taken from 26 outbreaks of commercial broiler chicken farms in the Beheira and Menofia governorates, Egypt, from January 2021 to March 2022. Adenoviruses genomes were detected in cloacal swabs of 10 flocks using polymerase chain reaction. Clinically, infected broiler chickens (Cobb, Ross, Indian River, Modified-Avian, and Arbor Acres) showed depression, ruffled feathers, retarded growth, and ascites, with mortality rates of 10-28%. The most common postmortem lesions were hydropericardium, yellowish enlarged liver with ecchymotic hemorrhages, pancreatitis, and enteritis. Histopathologically, intranuclear inclusion bodies, commonly basophilic type, were scattered in the hepatocyte, proventriculus, duodenum, kidney, pancreas, and spleen. In addition, depletion of lymphocytes in the bursa of Fabricius and the thymus was observed. Seven samples were selected for gene sequencing of the loop 1 region of the hexon gene. The sequence analysis revealed that all samples were identical and similar to fowl adenoviruses species D serotype 2/11, suggesting that this serotype was the predominant fowl adenoviruses circulating in the study location in the last two years. Further studies are required to address the pathogenicity of isolated fowl adenoviruses and evaluate the vaccine used to control fowl adenoviruses in Egypt. Keywords: Fowl adenoviruses, Hexon, Hydropericardium syndrome, Phylogenetic analysis, Polymerase chain reaction

Molecular detection of highly pathogenic avian influenza H5N8 in commercial broiler chicken farms from 2019 to 2022

Highly pathogenic avian influenza (HPAI) is a serious viral infection that causes massive economic losses in poultry. The current study investigated the HPAI virus prevalence in commercial broiler chicken flocks from 2019 to 2022. Organ samples, including trachea, cecal tonsils, spleen, brain, as well as tracheal and cloacal swabs, were harvested from 111 problematic broiler chicken flocks that suffered from variable mortalities accompanied with respiratory signs (103 H5-vaccinated and 8 nonvaccinated flocks) in Egypt during the observation duration. Molecular tools were used to analyze the samples, including real-time reverse transcription-polymerase chain reaction (rRT-PCR) and sequence analysis of some PCR positive strains. The results indicated that 24 flocks were positive for HPAI H5N8, representing 21.6%, with 22.3% (23/103) prevalence and 12.5% (1/8) detection in vaccinated and nonvaccinated flocks, respectively, and they were almost detected in the autumn and winter seasons. Phylogenetic evaluation of the hemagglutinin (HA) gene showed that the 6 Egyptian strains were clustered in clade 2.3.4.4b and allocated into 2 groups (I and II). The samples recovered in 2019 were clustered in new subgroup A, and samples recovered in 2020 to 2022 were clustered in new subgroup B with 10 nucleotide mutations (R72S, A83D, T140A). In conclusion, HPAI H5N8 is a serious threat even in vaccinated birds; to control such problems, periodic molecular monitoring with vaccine efficacy evaluation and the use of preventive strategies are recommended.

Farm-Level Risk Factors Associated With Avian Influenza A (H5) and A (H9) Flock-Level Seroprevalence on Commercial Broiler and Layer Chicken Farms in Bangladesh.

A cross-sectional study was conducted to identify farm-level risk factors associated with avian influenza A H5 and H9 virus exposure on commercial chicken farms in Bangladesh. For broiler farms, both H5 and H9 seropositivity were associated with visits by workers from other commercial chicken farms [odds ratio (OR) for H5 = 15.1, 95% confidence interval (CI): 2.8–80.8; OR for H9 = 50.1, 95% CI: 4.5–552.7], H5 seropositivity was associated with access of backyard ducks (OR = 21.5, 95% CI: 2.3–201.1), and H9 seropositivity with a number of farm employees (OR = 9.4, 95% CI: 1.1–80.6). On layer farms, both H5 and H9 seropositivity were associated with presence of stray dogs (OR for H5 = 3.1, 95% CI: 1.1–9.1; OR for H9 = 4.0, 95% CI: 1.1–15.3), H5 seropositivity with hatcheries supplying chicks (OR = 0.0, 95% CI: 0.0–0.3), vehicles entering farms (OR = 5.8, 95% CI: 1.5–22.4), number of farm employees (OR = 5.8, 95% CI: 1.2–28.2), and burying of dead birds near farms (OR = 4.6, 95% CI: 1.2–17.3); H9 seropositivity with traders supplying feed (OR = 5.9, 95% CI: 1.0–33.9), visits conducted of other commercial poultry farms (OR = 4.7, 95% CI: 1.1–20.6), number of spent layers sold (OR = 24.0, 95% CI: 3.7–155.0), and frequency of replacing chicken droppings (OR = 28.3, 95% CI: 2.8–284.2). Policies addressing these risk factors will increase the effectiveness of prevention and control strategies reducing the risk of avian influenza on commercial chicken farms.

Bird health and welfare in slower-growing hybrids on swedish commercial organic broiler chicken farms

Bird health and welfare in slower-growing hybrids on swedish commercial organic broiler chicken farms

Molecular characterization of chicken anemia virus in Guangxi Province, southern China, from 2018 to 2020.

BackgroundChicken anemia virus (CAV) causes chicken infectious anemia, which results in immunosuppression; the virus has spread widely in chicken flocks in China.ObjectivesThe aim of this study was to understand recent CAV genetic evolution in chicken flocks in Guangxi Province, southern China.MethodsIn total, 350 liver samples were collected from eight commercial broiler chicken farms in Guangxi Province in southern China from 2018 to 2020. CAV was detected by conventional PCR, and twenty CAV complete genomes were amplified and used for the phylogenetic analysis and recombination analysis.ResultsThe overall CAV-positive rate was 17.1%. The genetic analysis revealed that 84 CAVs were distributed in groups A, B, C (subgroups C1-C3) and D. In total, 30 of 47 Chinese CAV sequences from 2005-2020 belong to subgroup C3, including 15 CAVs from this study. There were some specific mutation sites among the intergenotypes in the VP1 protein. The amino acids at position 394Q in the VP1 protein of 20 CAV strains were consistent with the characteristics of a highly pathogenic strain. GX1904B was a putative recombinant.ConclusionsSubgroup C3 was the dominant genotype in Guangxi Province from 2018–2020. The 20 CAV strains in this study might be virulent according to the amino acid residue analysis. These data help improve our understanding of the epidemiological trends of CAV in southern China.

Quantification and Trends of Antimicrobial Use in Commercial Broiler Chicken Production in Pakistan.

Antimicrobial resistance (AMR) is a global health challenge and antimicrobial use (AMU) in the livestock sector has been considered as one of the contributing factors towards the development of AMR in bacteria. This study summarizes the results of a point prevalence survey conducted to monitor farm-level AMU in commercial broiler chicken farms in Punjab and Khyber Pakhtunkhwa (KPK) provinces of Pakistan. A cross-sectional study was conducted to quantify AMU and to check seasonal variations of AMU in 12 commercial broiler chicken farms (six from each province) during the summer and winter seasons of the year 2020–2021. AMU was recorded using three AMU metrics: kg, mg per population correction unit (mg/PCU), and mg/kg of final flock weight. A total of 22 antimicrobial drugs (348.59 kg) were used for therapeutic or prophylactic purposes in surveyed broiler chicken farms. The total combined AMU for all the broiler chicken farms was 462.57 mg/PCU. The use of most of the antimicrobials increased during winter flocks compared to summer. The top three antimicrobial drugs used during the summer were neomycin (111.39 mg/PCU), doxycycline (91.91 mg/PCU), and tilmicosin (77.22 mg/PCU), whereas doxycycline (196.81 mg/PCU), neomycin (136.74 mg/PCU), and amoxicillin (115.04 mg/PCU) during the winter. Overall, 60% of the antibiotics used in broiler chicken were critically important antimicrobial classes (CIA) for human medicine as characterized by the World Health Organization. Our findings showed high AMU in broiler chicken production and a call for urgent actions to regulate CIA use in food animals in Pakistan. This baseline survey is critical for the design and implementation of a subsequent national level AMU surveys that can include additional farming types, animals’ species, and geographical locations over a longer period of time.

Circulation of Recently Reported Sub-genotype VII1.1 of Newcastle Disease Virus in Commercial and Backyard Chicken in north of Iran

BACKGROUND: Newcastle disease virus (NDV) majorly infects the poultry, and despite high rates of vaccination, it is still circulating in different geographical regions. Due to the high mortality rate, the economic loss of Newcastle disease (ND) is enormous. OBJECTIVES: The molecular characterization of NDV isolates from chicken farms in Northern Iran, during 2017-2018, was the main goal of this study. METHODS: We isolated and characterized five NDVs from commercial broiler and backyard chicken farms during severe disease outbreak. The partial coding sequence of fusion (F) genes of isolates was determined and compared with those of other published NDVs. RESULTS: Phylogenetic analysis revealed that all of the isolates were grouped into sub-genotype VII.1.1 (formerly known as VIIl). All isolates carried multi‐basic amino acid residues at the cleavage site of fusion protein, typical of virulent strains. Studied NDV isolates had high homology with the prevalent genotype NDV strains that currently circulate in China and Republic of Korea (96.94%). CONCLUSIONS: Our results suggested that NDV sub-genotype VII.1.1 (VIIl), circulating among chicken farms, may be a dominant sub-genotype. Considering the genetic variation between the used vaccine strains (B1, LaSota, and Clone 30, all belonging to genotype II) and circulating NDVs, it is recommended that a contemporary homologous virus should be developed as the vaccine strain to avert the outbreaks of genotype VII viruses.

Impacts of Short-Term Antibiotic Withdrawal and Long-Term Judicious Antibiotic Use on Resistance Gene Abundance and Cecal Microbiota Composition on Commercial Broiler Chicken Farms in Québec.

The ever-increasing problem of antibiotic resistance makes routine use of antibiotics in animal production no longer considered as a reasonable and viable practice. The Chicken Farmers of Canada have developed and are implementing an Antimicrobial Use Reduction Strategy, which has the ultimate goal of eliminating the preventive use of medically important antibiotics in broiler chicken and turkey production. However, very little is known about the real overall impact of an antibiotic use reduction strategy in complex ecosystems, such as the bird intestine or the commercial broiler chicken farm. The main objectives of the present study were to compare the abundance of antibiotic resistance-encoding genes, characterize the intestinal microbiota composition, and evaluate the presence of Clostridium perfringens, in six commercial poultry farms adopting short-term antibiotic withdrawal and long-term judicious use strategy. Implementing an antibiotic-free program over a 15-months period did not reduce the abundance of many antibiotic resistance-encoding genes, whereas the judicious use of antibiotics over 6 years was found effective. The short-term antibiotic withdrawal and the long-term judicious use strategy altered the intestinal microbiota composition, with the Ruminococcaceae and Lachnospiraceae families being negatively impacted. These findings are in agreement with the lower production performance and with the increased C. perfringens populations observed for farms phasing out the use of antibiotics. Adopting a conventional rearing program on commercial broiler chicken farms selected for specific antibiotic resistance-encoding genes in many barns. This study highlights the potential impacts of different rearing programs in poultry production and will help guide future policies in order to reduce the use of antibiotics while maintaining production performance.

A Cross-Sectional Study of Antimicrobial Usage on Commercial Broiler and Layer Chicken Farms in Bangladesh.

Commercial poultry production is growing rapidly in Bangladesh to address the increasing demand for poultry meat and eggs. Challenges faced by producers include the occurrence of poultry diseases, which are usually treated or controlled by antimicrobials. A cross-sectional study was conducted on 57 commercial layer and 83 broiler farms in eight subdistricts of the Chattogram district, Bangladesh, to assess antimicrobial usage in relation to clinical signs observed in chicken flocks on these farms. Of the 140 commercial chicken farms, 137 (97.9%) used antimicrobials and 24 different antimicrobial agents were administered. On layer farms, the most commonly used antimicrobials were ciprofloxacin (37.0% of farms, 20/54), amoxicillin (33.3%, 18/54), and tiamulin (31.5%, 17/54), while on broiler farms, colistin (56.6%, 47/83), doxycycline (50.6%, 42/83), and neomycin (38.6%, 32/83) were most commonly administered. Only 15.3% (21/137) of farmers used antimicrobials exclusively for therapeutic purposes, while 84.7% (116/137) of farmers used them prophylactically, administering them either for prophylactic purposes only (22.6% of farmers, 31/137) or in combination with therapeutic purposes (62.1% of farmers, 85/137). About 83.3% (45/54) of layer farmers were selling eggs while antimicrobials were being administered compared to 36.1% (30/83) of the broiler farmers selling broiler chickens while administering antimicrobials. Overall, 75.2% (103/137) of farmers reported clinical signs for which they administered antimicrobials, while 24.8% (34/137) of farmers reported no clinical signs but still administered antimicrobials. Respiratory signs (71.8% of farms with clinical signs, 74/103) were most commonly reported, followed by enteric signs (32.0%, 33/103) and increased mortality (16.5%, 17/103). About 37.2% (51/137) of farmers bought antimicrobials exclusively from feed and chick traders, followed by veterinary medical stores (35.0%, 48/137). Purchasing antimicrobials from feed and chick traders was more common among broiler than layer farmers. It is recommended that commercial poultry farmers should keep records of antimicrobials used with dosage and duration of administration along with indication of use. This would allow farmers and veterinarians to review if antimicrobial usage had the desired effects and to evaluate the appropriate use of antimicrobial agents under an antimicrobial stewardship approach.

Patterns of Avian Influenza A (H5) and A (H9) virus infection in backyard, commercial broiler and layer chicken farms in Bangladesh.

In order to control Highly Pathogenic Avian Influenza (HPAI) H5N1 and Low Pathogenic Avian Influenza (LPAI) H9N2 virus spread in endemically infected countries, a detailed understanding of infection patterns is required. We conducted cross-sectional studies in Bangladesh in 2016 and 2017, on 144 backyard, 106 broiler and 113 layer chicken farms. Although all sampled birds were negative for H5 virus by RT-PCR, H5 antibodies were detected in unvaccinated birds on all three farming systems. Higher H5 antibody prevalence was observed in ducks raised on backyard farms, 14.2% (95% CI: 10.0%-19.8%), compared to in-contact backyard chickens, 4.2% (95% CI: 2.8%-6.1%). The H5 antibody prevalence was lower in broiler chickens, 1.5% (95% CI: 0.9%-2.5%), compared to layer chickens, 7.8% (95% CI: 6.1%-9.8%). H9 viruses were detected by RT-PCR in 0.5% (95% CI: 0.2%-1.3%) and 0.6% (95% CI: 0.3%-1.5%) of broilers and layers, respectively, and in 0.2% (95% CI: 0.0%-1.2%) of backyard chickens. Backyard chickens and ducks showed similar H9 antibody prevalence, 16.0% (95% CI: 13.2%-19.2%) and 15.7% (95% CI: 11.3%-21.4%), which was higher compared to layers, 5.8% (95% CI: 4.3%-7.6%), and broilers, 1.5% (95% CI: 0.9%-2.5%). Over the course of a production cycle, H5 and H9 antibody prevalence increased with the age of backyard and layer chickens. Usually, multiple ducks within a flock were H5 antibody positive, in contrast to backyard chickens, broilers and layers where only individual birds within flocks developed H5 antibodies. Our findings highlight low virus circulation in healthy chickens of all production systems in Bangladesh, which is in contrast to high virus circulation reported from live bird markets. Data generated in this project can be used to adopt risk-based surveillance approaches in different chicken production systems in Bangladesh and to inform mathematical models exploring HPAI infection dynamics in poultry from the source of production.

Impacts of antibiotic reduction strategies on zootechnical performances, health control, and Eimeria spp. excretion compared with conventional antibiotic programs in commercial broiler chicken flocks

Increasing efforts have been made in recent years to reduce antimicrobial use in animal production. The objective of this prospective study was to evaluate, in commercial broiler chicken farms, 2 antibiotic reduction strategies that eliminated the use of antibiotics important for human medicine, in comparison with the conventional use of antibiotics. On 7 broiler chicken farms, a house was allocated to the antibiotic reduction treatments for 6 consecutive flocks, whereas a similar house on the same premises was assigned to the conventional use of antibiotics (CONV) for 6 consecutive flocks. The antibiotic reduction strategies consisted of continuous in-feed use of ionophores (TX1) and continuous in-feed use of ionophores with butyric acid (TX2). In the 84 flocks, zootechnical performance was recorded, lesion scoring at 21 and 28 D of age was performed, and fecal samples were recovered during grow out for Eimeria spp. oocysts counts. There was no statistical difference between TX1, TX2, and CONV for weights at slaughter, feed conversion ratios, average daily gains, age at slaughter, total mortalities, and condemnations. The probability of identifying oocysts in the fecal samples significantly increased with the age of the flock, but there was no significant treatment effect between 7 and 16 D of age. At 19 D of age, the probability of a sample containing oocysts was higher in TX1 than in CONV, but TX2 was not statistically different from TX1 and CONV. Predicted oocysts per gram in CONV flocks were significantly lower between 22 and 34 D of age than in TX1 and TX2 flocks, whereas there were no significant differences between TX1 and TX2 for all ages. Lesion scoring of the gastrointestinal system showed no differences for coccidiosis scores between TX1, TX2, and CONV. No lesions of necrotic enteritis were observed. In conclusion, it was possible to adequately control intestinal diseases and maintain zootechnical performances by relying exclusively on ionophores, when compared with broiler chicken flocks using standard shuttle programs with antibiotic growth promoters.

Contaminated in-house environment contributes to the persistence and transmission of NDM-producing bacteria in a Chinese poultry farm

While carbapenem use is prohibited in the poultry production chain and carbapenem-resistant Enterobacteriaceae (CRE) are absent from hatchery farms, New Delhi metallo-β-lactamase-producing CRE contamination of commercial broiler chicken farms (grow-out farms) can occur via living hosts such as flies. However, it is not known whether the inanimate factors from in-house environment play a role in the persistence of CRE on commercial farms. Herein, we monitored one typical broiler house in Hebei Province, China, from January 2017 to April 2018. We collected 350 cloacal samples from four broiler batches along with 582 environmental samples (194 in the raising period and 388 in the vacancy period) from sites including the surfaces of drooping boards, feeding troughs, nipple drinkers, corridor floors, sewage trenches, and air. All samples were screened for blaNDM and cultured for NDM-producing isolates. The resistance profiles, genotypes, and genetic context of blaNDM in CRE isolates were further characterized. Results showed that 1-day-old broilers, which were transferred from a hatchery farm and negative for CRE, acquired blaNDM within 24 h of transfer (2 days of age), with a detection rate of up to 18.6%. High blaNDM detection rates (26.8%–31.4%) were obtained among all environmental samples except air after standard cleaning and disinfection during the vacancy period. blaNDM carriage rates (52.9%–72.9%) within the flocks remain stable and high across the next three broiler batches. Overall, 279 NDM-producing bacteria, including 259 Enterobacteriaceae (8 species), 14 Morganellaceae (3 species), three Alcaligenes faecalis and three Pseudomonas putida isolates, were recovered from 85 (24.3%) cloacal and 101 (17.4%) environmental samples. Three NDM variants, including NDM-5 (n = 181), NDM-1 (n = 92), and NDM-9 (n = 3), and a novel NDM-like-metallo-β-lactamase (NLM, n = 3) were identified among the samples. The predominant NDM-producing CRE species among the samples were Klebsiella pneumoniae (CRKP; 32.6%, n = 91) and Escherichia coli (CREC; 27.2%, n = 76). Both clonal and horizontal transmission of blaNDM and an overlap of sequence types (STs) were observed in both CREC and CRKP from chicken and environmental samples. Notably, ST6751 CREC and ST37 CRKP persisted throughout the 16-month surveillance period. IncX3 (n = 197, 7 species), IncA/C2 (n = 41, 5 species), and IncFII (n = 8, E. coli) were the three major blaNDM-carrying plasmid types among the isolates. Although routine cleaning and disinfection procedures and “all-in/all-out” management were performed, once introduced to the farm environment, a diverse range of NDM-positive isolates may survive and persist, becoming an important reservoir of NDM-positive CRE for broiler chickens. Therefore, cleaning and disinfection procedures should be improved on poultry farms to avoid cross-contamination of NDM-producing bacteria between different batches of chickens, as well as further downstream in the poultry production chain.

Effect of probiotic preparations (EM) on productive characteristics, carcass composition, and microbial contamination in a commercial broiler chicken farm

This experiment evaluated the effect of Pro-Biotyk (Em-15) and EMFarma™ probiotics on body weight, feed intake and conversion, carcass traits, and microbial contamination in a poultry house. The probiotic preparations caused a nonsignificant increase in body weight (42 days), feed intake, and feed conversion ratio (1–42 days) and a nonsignificant decrease in chicken mortality from 4 weeks of rearing. Chickens exposed to probiotics did not differ significantly in preslaughter body weight, carcass weight, dressing percentage, and the content of carcass components. The carcasses from experimental chickens had a lower percentage of breast muscle, leg muscle, abdominal fat, and neck, as well as a higher percentage of skin with subcutaneous fat, wings, and remainder of carcasses compared with the carcasses from control birds. The probiotic preparations used in this study were highly effective as auxiliary disinfectants.

Infectious Bursal Disease Virus: Molecular Epidemiologic Perspectives and Impact on Vaccine Efficacy Against Avian Influenza and Newcastle Disease Viruses.

Infectious bursal disease (IBD) virus (IBDV) is the causative agent of a highly contagious and immunosuppressive disease of chickens with huge economic losses to the poultry industry despite extensive vaccination. Analysis of isolated IBDV field strains from vaccinated birds would greatly improve the current immunization regimens and support the development of vaccines that offer better immunity. The study investigated the genetic characteristics and pathologic features of IBDVs in commercial broiler chicken farms, as well as the effect of IBDV infection on the efficacy of vaccination against avian influenza virus (AIV) and Newcastle disease virus (NDV) under field conditions. A preliminary diagnosis of IBD was made on the basis of the flock history and the characteristic gross pathologic findings. Microscopically, lymphoid depletion in bursal follicles with infiltration of lymphomononuclear cells along with cystic cavitations reflected the IBDV infection. The molecular analysis confirmed the IBDV infection in (57.1%) of tested flocks. Upon phylogenetic analysis of the VP2 hypervariable region of 14 Egyptian IBDVs, most viruses (n = 12) were clustered within the genogroup 3, while two viruses were closely related to attenuated vaccine isolates in genogroup 1. The analysis of the amino acid (aa) sequences revealed that most of the strains possessed five consistent aas at the VP2 protein (222A, 242I, 256I, 294I, and 299S), which are characteristic for the very virulent IBDV (vvIBDV). Serology indicated the immunosuppressive effect of IBDV, which is represented by a decrease (1.6-2.6 and 1.4-2.6 mean log 2) in the hemagglutination inhibition titer of the low pathogenic AIV subtype H9N2 and NDV, respectively. The examined IBDVs showed a high mutation rate within the hypervariable domain of the VP2 peptide. The results highlighted the need for carrying out an inclusive surveillance of IBDV infections in chicken flocks in Egypt.

Associations between qualitative behaviour assessments and measures of leg health, fear and mortality in Norwegian broiler chicken flocks

Qualitative behavioural assessments (QBA) is an animal-based welfare measure that has been included in several on-farm welfare assessment protocols, including the Welfare Quality® (WQ) protocol for poultry. However, there is a scarcity of information about how it relates to other animal-based welfare indicators. The aim of this study was therefore to investigate the associations between QBA and selected animal-based welfare indicators commonly used for the assessment of broiler chicken welfare, i.e. lameness, foot pad dermatitis (FPD), fear of humans (touch test), and mortality.A total of 50 commercial broiler chicken farms were visited by one observer who conducted on-farm welfare assessments using the WQ protocol. Assessments were done close to the time of slaughter (between day 27 and 34). QBA was analysed using principal component analysis (PCA), revealing two main components, labelled arousal (PC1) and mood (PC2). The scores for the other welfare indicators were categorised into dichotomous (touch test) or ordinal scales (gait score, footpad dermatitis score and mortality) to deal with skewed distributions caused by homogenous data. To investigate the associations between QBA and the other welfare indicators, we ran logistic and ordinal logistic regression models with these welfare measures as outcomes, and the two components of QBA as the predictors.Significant negative associations were found between both components of QBA and the chickens’ fear of humans, as measured using the touch test. In other words, flocks with higher scores on both mood and arousal were less likely to have any chickens that were possible to touch by the assessor. A possible interpretation of these associations is that both QBA components may indicate greater liveliness in birds that did not accept to be touched by the observer. Flocks with a higher arousal score, as measured by the first component of QBA (PC1), were also less likely to be in a higher mortality category. For the other selected animal-based measures, there were no associations with QBA. We conclude that QBA needs thorough validation for the routine use in the assessment of broiler chicken welfare, but that the method may provide useful supplementary information in overall welfare assessments. This information may be particularly valuable in a production system, like the broiler industry, where management is highly standardised, sometimes resulting in little between-flock variation in other welfare measures.

Greenhouse Gas Emission of Broiler Chicken Production in Malaysia using Life Cycle Assessment Guidelines: A Case Study

The aim of this research was to evaluate the level of greenhouse gas emission from broiler chicken farming industry in Malaysia. In order to achieve that, Life Cycle Assessment method was chosen as a framework to complete the task. A case study was conducted at a broiler chicken farm to gather the data and information related to the broiler chicken production. Cradle-to-gate assessment including distribution stage was conducted based on the ISO14040/1044 guidelines. Inventory data for this case study was gathered in collaboration with one of the selected case study broiler chicken farm company. Greenhouse gas emission that consists of several most affected gases such as carbon dioxide, methane and nitrous oxide was studied. Result shows that the highest carbon dioxide emission came from manure, which accounted for 1,665,342 kg CO2 equivalent per total broilers while the highest methane emission came from feed, which accounted for 126,207.84 g CH4 equivalent per total broilers. For nitrous oxide emission, the highest values came from bedding which accounted for 20,316.87 g N2O equivalent per total broilers in the commercial modern broiler chicken farm. In this case study, it can be concluded that manure gives the most prominent effect to the greenhouse gas emission followed by feed and bedding materials.

Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population.

Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.