Escherichia coli is the most common bacterial cause of infections in poultry farms. It is known for its genetic heterogenicity that complicates the protection of poultry health through ...immunoprophylaxis. In farms with continuous problems with colibacillosis, autogenous E. coli vaccine was implemented to the vaccination program instead of commercial vaccines. In this study, we investigated the effect of the autogenous vaccine on E. coli phylogroup diversity on 2 broiler breeder farms with 4 and 5 flocks, respectively. The first flocks on both farms were vaccinated with commercial vaccines, while application of autogenous vaccine was introduced in the second flock on both farms. In total, 113 strains were selected based on the target organs and age of chickens. Targeted organs were the peritoneum, liver, oviduct, and bone marrow, and analyzed strains were isolated from chickens older than 21 wk of age when problems with colibacillosis start emerging. The strains were phylotyped by PCR and allocated to phylogroups A, B1, B2, C, D, E, F or clades I–V. The results showed that autogenous vaccine could significantly affect the phylogroup shift of the strains. On farm A, application of the autogenous vaccine induced significantly lower prevalence (P = 0.01) of the phylogroups represented in the vaccine among the strains later isolated from the vaccinated flock, while on farm B, the results showed a decrease in the phylogenetic diversity with a dominant prevalence of group B2 despite the vaccine application. The results indicate that implementation of the autogenous vaccine can repress the majority of the strains, but also be unable to eliminate the presence of certain phylogroups, and thus lead to strain shift. Further detailed analyses of multilocus sequence typing and virulence genes will elucidate the pathogenic potential and selection of certain strains, with emphasis on B2 phylogroup.
Newcastle disease (ND) is one of the classic viral infections of poultry which resists all the efforts of eradication. Newcastle disease virus (NDV) strain ZG1999HDS was isolated during the outbreak ...in 1,999 at a broiler farm in Croatia. Previous trials in chickens confirmed it to be a lentogenic pathotype and immunogenic by stimulating humoral and cell mediated immunity. Further characterization by deduced amino acid sequence at the cleavage site of fusion protein confirmed its lentogenic nature, and in vitro tests its oncolytic capacity. Owing to its immunogenicity, strain ZG1999HDS is considered for vaccine development. In this study, 1-day-old chicks were vaccinated using strain ZG1999HDS oculonasally or by nebulization. Strain ZG1999HDS induced humoral immune response in both immunized groups The cell-mediated immune response occurred earlier in the group immunized by nebulization, as shown by a higher frequency rate of T and B lymphocytes, and significantly higher expression of IFN-α in respiratory organs and IFN-γ expression in the spleen. Viral genomic RNA was not detected in investigated organs. Thus, NDV strain ZG1999HDS is immunogenic when administered by means of nebulization or oculonasally without any adverse effects and is therefore suitable for further research and vaccine development. Further research is needed regarding its tropism.
Fowl typhoid is a septicemic disease caused by
subsp.
serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys, although it has been reported in ...various animal species and sporadically in humans. Here, we present a case of a fowl typhoid outbreak on a turkey poult farm where the source of infection was the hatchery. The birds started showing symptoms of growth retardation at 21 days of age, after which the mortality rates gradually started to increase. Post mortem examination revealed that the main lesions were granulomatous proliferations in the small intestines. The results of the histopathological examination indicate that the severity of the infection was alleviated by the application of phytogenic mixtures and probiotics as a supportive treatment, even though the affected flock was eventually culled at 60 days of age. The farmer was advised to apply more strict biosecurity measures to prevent the spread of the disease on the farm and try to eradicate the pathogen from the barn. Since the outbreak, there have been no recurrent infections.
Newcastle disease (ND) is a highly contagious avian disease. Global control of ND is mainly based on vaccination of poultry; however, reported outbreaks of ND in vaccinated flocks indicate a constant ...need to re-evaluate the existing vaccines and a development of the new ones. In this study, 4-week-old male chickens of the layer commercial hybrid were immunized oculonasally with a commercial NDV live La Sota vaccine (LS group), a suspension of lyophilized NDV strain ZG1999HDS (ZG group), or saline (Control (K) group). Antibody response was determined by haemagglutination inhibition (HI) assay. Cell-mediated immunity (CMI) was characterized by immunophenotyping of leukocyte's and T-lymphocyte's subpopulations (flow cytometry). Applied NDV strains did not cause any adverse reaction in treated chickens. Both strains induced the significantly higher HI antibody response in comparison to the control group, and overall antibody titer was higher in ZG group than in LS group. CMI, manifested as a higher proliferation of B- and T-helper cells, yielded better results in the ZG groups than in the LS group. Based on the obtained results, we conclude that the strain ZG1999HDS is immunogenic and is a suitable candidate for further research and development of poultry vaccines.
is the main bacterial cause of major economic losses and animal welfare issues in poultry production. In this study, we investigate the effect of an autogenous vaccine on
strains longitudinally ...isolated from broiler breeder flocks on two farms. In total, 115
isolates were sequenced using Illumina technologies, and compared based on a single-nucleotide polymorphism (SNP) analysis of the core-genome and antimicrobial resistance (AMR) genes they carried. The results showed that SNP-based phylogeny corresponds to a previous multilocus-sequence typing (MLST)-based phylogeny. Highly virulent sequence types (STs), including ST117-F, ST95-B2, ST131-B2 and ST390-B2, showed a higher level of homogeneity. On the other hand, less frequent STs, such as ST1485, ST3232, ST7013 and ST8573, were phylogenetically more distant and carried a higher number of antimicrobial resistance genes in most cases. In total, 25 antimicrobial genes were detected, of which the most prevalent were
(
) (100%),
(71.3%) and
(
) (13.91%). The frequency of AMR genes showed a decreasing trend over time in both farms. The highest prevalence was detected in strains belonging to the B1 phylogenetic group, confirming the previous notion that commensal strains act as reservoirs and carry more resistance genes than pathogenic strains that are mostly associated with virulence genes.
This study aimed to investigate dust and bacterial air contamination in a broiler house during different seasons. The study was carried out in commercial housing conditions during five weeks of the ...rearing cycle in summer and winter. The total dust concentration ranged from 1.90 to 4.50 mg/m3 in summer and from 2.80 to 5.10 mg/m3 in winter. The total bacterial count ranged from 2.85 × 104 to 1.03 × 105 CFU/m3 in summer and from 2.12 × 104 to 2.28 × 105 CFU/m3 in winter. The study results showed the dust concentration to be increased in winter as compared to summer, yielding a significant correlation (r = 0.602, p < 0.05) with a significantly higher airborne bacterial count in winter (p < 0.001). Furthermore, dust concentration showed significant correlations (p < 0.05) with air temperature (r = −0.418), relative humidity (r = 0.673), and broiler activity (r = 0.709), while bacterial count yielded significant correlations (p < 0.05) with air temperature (r = −0.756), relative humidity (r = 0.831), and airflow rate (r = 0.511). The results obtained in the study can prove useful in the field. Seasonal variability in dust and bacterial air contamination should be considered in the development of guidelines or standards of air quality in broiler housing and evaluation of the effectiveness of remedial strategies.
Escherichia coli (E. coli) is one of the most common bacterial causes of infection in poultry farming. Whether the infection is localized or systemic, a primary or secondary disease, it is most ...frequently treated through the application of wide-spectrum antimicrobials. Excessive use of antimicrobials in agriculture is significantly contributing to the worldwide rise of antimicrobial resistance, but is also very expensive and often ineffective in the long term. Here, we present a case where a colibacillosis outbreak on a family farm of laying hens was treated using an autogenous vaccine. The birds had septicemia, cellulitis, and severe skin wounds. They were not vaccinated against E. coli, and did not receive any antimicrobials previously. E. coli strains were isolated from the daily mortalities on the farm and used for preparation of the vaccine. Each bird was given an intramuscular injection of the autogenous vaccine. The immunogenicity of the vaccine was tested by the determination of specific antibody levels in the sera of the birds using the in-house ELISA. Shortly after vaccination, the morbidity and mortality rates significantly decreased, and egg production was improved. The application of the autogenous vaccine served as a curative and preventive measure, and has proven to be a very efficient method of antimicrobial therapy.
Fungi are present in abundance in poultry housing. The aim of the study was to assess the effect of season and microclimate parameters in poultry housing on fungal flora in the air and broiler ...trachea in commercial fattening conditions. The study was conducted in summer and winter. Study results indicated seasonal impact and association between fungal flora composition in housing air and broiler trachea. However, the total fungal count in housing air was significantly higher in summer and in broiler trachea in winter, both significantly correlated with indoor relative humidity and ammonia concentration. There was no significant correlation between outdoor and indoor air temperature, relative humidity and airflow rate, respectively. Study results suggested that environmental determination of fungi should be accompanied by their determination in broilers. In addition, seasonal impact on fungal contamination should be associated with microclimate conditions in the poultry house rather than the season itself. The fungi detected and the results obtained have implications not only for broiler health but also for the health of humans working in such environments.
•50 % of the most prevalent virulence genes (>85 %) were toxins/bacteriocin-related.•The most prevalent STs were ST95, ST117, ST390 and ST23.•Application of autogenous vaccine led to lower genetic ...diversity of E. coli.
Colibacillosis is one of the most common problems in the poultry industry. Escherichia coli strains on farms are often genetically diverse and therefore commercial vaccines provide little protection to the flocks. Here, we investigated the effect of the autogenous E. coli vaccines on the prevalence of 84 virulence-associated genes in E. coli isolated from four and five consecutive flocks on two broiler breeder farms, respectively. 115 E. coli isolates were sequenced using Illumina technologies, and compared based on both their set of housekeeping genes and their virulence profiles, defined through the composition of virulence genes. Predominantly, phylogenetic analysis showed obvious distinction between the isolates originating from different farms suggesting spatial-dependent transmission of pathogenic strains. We detected 23 sequence types, while 52.58 % of the isolates belonged to two clonal complexes. Analysis of the virulence genes showed highest prevalence (>85 %) of feoB, uspA, uspB, uspG, uspE, fimH, ompA, astA, focA, hlyE, uspC, crl, csgA, ompT and iss, of which 50 % are toxin associated genes, demonstrating the importance of competition in the pathogenesis process. Interestingly, usp genes, which are primarily associated with uropathogenic E. coli strains, were detected in all investigated isolates. The heatmap analysis demonstrated that strains belonging to same phylogenetic groups often share similar virulence profiles, confirming the usefulness of quick tests for phylogenetic typing. However, our results suggest the need to update the list of the minimal predictors used for the identification of avian pathogenic strains. Overall results indicate that continuous application of autogenous vaccines led to lower genetic diversity of E. coli housekeeping genes, but not virulence genes.
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•Dietary fish oil has positive influence on survival rate.•PUFA/MUFA ratio is negatively correlated to Jamaican field cricket mortality.•Dietary linseed oil increases linolenic acid ...amounts in tissues.•Only fish oil increases EPA and DHA amounts in tissues.
This study was performed to investigate the influence of linseed, fish, pumpkin seed and sunflower oil on the Jamaican field cricket’s survival rate, growth and fatty acid profile. Fatty acids were analysed by gas chromatography mass spectrometry as fatty acid methyl esters in the homogenates of whole crickets. Survival rate was influenced by oil type and oil content. With an increase in the pumpkin seed and linseed oil percentage survival rate decreased (from 45.3 to 34.0% for the pumpkin and from 36.7 to 24.12% for linseed), while with an increase in fish oil, the survival rate increased (from 30.7 to 45.4%). Oleic acid and total monounsaturated fatty acids had the strongest positive effect on cricket survival and polyunsaturated/monounsaturated fatty acids ratio had the highest negative correlation with cricket survival. The most abundant fatty acids in all groups were linoleic, oleic and palmitic. The levels of individual fatty acids varied considerably between different treatments. Linseed oil significantly increased the content of linolenic acid (7.32% for 3% supplementation to 11.27% for 5% supplementation) and strongly decreased the n6/n3 ratio, but the EPA and DHA content was not detectable. In the fish oil fed crickets EPA and DHA content was detectable ranging for EPA from 0.78 to 1.35% and for DHA from 0.16 to 0.29% and the n6/n3 ratio was decreased. In the pumpkin seed and sunflower oil treated insects the n6/n3 ratio was very high due to the high content of linoleic acid. In conclusion, dietary linseed and fish oil could be an interesting strategy to manipulate cricket fatty acid profile to make them more interesting from a nutritional standpoint. Monounsaturated fatty acids have a positive influence on cricket survival, and therefore, they should not be neglected in feed formulation for large scale cricket production.
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