| Project
Title: |
Evaluation
of fowl pox strains free of reticuloendotheliosis virus as vaccines for
use in Australian poultry flocks |
| RIRDC
Project No.: |
CSA-16A |
| Researcher: |
Dr.
David Boyle |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GEELONG VIC 3220 |
| Phone: |
(03)
5227 5018 |
| Fax: |
(03)
5227 5555 |
| Email: |
David.Boyle@csiro.au |
| Objectives |
· To undertake vaccine
efficacy, safety and adventitious agent testing on reticuloendotheliosis
free fowl pox virus strains derived from Australian fowl pox isolates.
|
| Background |
The
only fowl pox vaccine stain currently available for use in Australia has
proven ineffective in controlling fowl pox disease in some circumstances.
Although suitable for day old vaccination, this strain has not proven effective
for revaccination of broiler breeder flocks coming into production. Earlier
studies undertaken by this research group have shown that the previously
available FPV S vaccine is contaminated with REV, with the REV provirus
being integrated into the FPV genome. RIRDC previously funded a small project
to remove the REV provirus from the FPV S vaccine and two field strains.
In that project, this CSIRO research group successfully removed the integrated
REV genome from FPV S vaccine and from two field strains, FPV 59vac and
62vac. Preliminary in vivo testing of these strains has shown them
to be free of REV contamination. The current project was aimed at undertaking
vaccine efficacy, safety and adventitious agent testing prior to the conduct
of a field trial for the registration of one of these strains for use in
Australian poultry flocks. |
| Research |
A
vaccination and challenge experiment was conducted with the FPV strains
in chickens to select a strain for further development. Intervet Pty. Ltd.,
the commercial partner in this project, prepared master and working seeds
and pilot vaccine lots of this strain. Safety and potency tests and CIT
(adventitious agent tests) as per "European Pharmacopoeia, Fourth Edition
September 2001" were conducted on master and working seeds and pilot vaccine
lots of the candidate fowl pox vaccine. |
| Outcomes |
The
FPV vaccine based on FPV 85a (a REV free derivative of field strain FPV
62vac) was shown to meet the "European Pharmacopoeia, Fourth Edition, September
2001" requirements for safety, potency and freedom from adventitious poultry
pathogens (CIT test). |
| Implications |
The
FPV strain that has been developed will need to be evaluated in field trials
to be conducted by Intervet Pty. Ltd. to ascertain if it is suitable for
use by the Australian poultry industry for the control of fowl pox disease.
Subject to the suitability of the candidate vaccine for use in control
of fowl pox in Australia being demonstrated in these field trials and the
vaccine subsequently being registered for use for this purpose, then the
Australian poultry industries will have available an alternative, more
immunogenic vaccine for the control of fowl pox in the future. |
| Publications |
Hertig, C.H., Coupar, B.E.H.,
Gould, A.R. and Boyle, D.B. (1997) Field and vaccine strains of fowlpox
virus carry integrated sequences from the avian retrovirus, reticuloendotheliosis
virus. Virology235: 367-376.
|
| Project
Title: |
Characterisation
of IBV from broilers |
| RIRDC
Project No.: |
CSA-27A |
| Researcher: |
Dr.
Jagoda Ignjatovic, Dr.Sandra Sapats and Ms. Gaylene Gould |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GeelonG Vic 3216 |
| Phone: |
(03)
5227 5000 |
| Fax: |
(03)
5227 5555 |
| Email: |
Jagoda.Ignjatovic@csiro.au |
| Objectives |
· To attempt
the isolation of infectious bronchitis virus (IBV) from samples collected
from broilers with suspected IBV involvement.
· To sequence
the S1 glycoprotein of any isolated IBVs.
|
| Background |
Respiratory
disease with elevated mortality was observed on a number of broiler farms
during a three month period from December 2002 to February 2003 in the
state of New South Wales. Infectious bronchitis virus was suspected to
be the cause. |
| Research |
Samples
were obtained from 23 broiler farms in three states. Virus isolation was
attempted from all farms by passaging field samples in embryonated specific
pathogen free chicken eggs. Virus isolation was confirmed using monoclonal
antibodies in an antigen ELISA. Sequencing of the S1 gene of isolated IBVs
was then undertaken. |
| Outcomes |
IBV
was isolated from 12/23 broiler farms in NSW that were suspected of having
respiratory problems due to IBV. In the majority of cases, IBV was the
only agent present in the sample, although Newcastle disease virus was
also detected in 2/11 IBV-positive samples. In all the NSW cases the same
genetic type of IBV virus was involved. Sequencing of the protective S1
antigen of this virus and of four IBV vaccines used on these farms indicated
that the NSW isolate is a new type of IBV, not seen previously. Additionally,
this virus differs significantly at a genetic level from all vaccine viruses
available. This suggests that the currently available IBV vaccines would
not control infections caused by this virus. |
| Implications |
Although
the sequencing data strongly suggest that a new vaccine would be needed
for control of this virus, only cross-protection studies would establish
this for certain. |
| Project
Title: |
Determination
of the genomic sequence of Mycoplasma gallisepticum |
| RIRDC
Project No.: |
UM-45J |
| Researcher: |
A/Prof.
Glenn Browning and Dr. Philip Markham |
| Organisation: |
The
University of Melbourne
School of Veterinary Science
Cnr Park Drive and Flemington
Road
PARKVILLE VIC 3052 |
| Phone: |
(03)
8344 7342 |
| Fax: |
(03)
8344 7374 |
| Email: |
glenfb@unimelb.edu.au |
| Objectives |
· To lay a foundation
for subsequent studies to improve the performance of Mycoplasma
vaccines and to improve diagnosis of mycoplasmosis by determining the complete
genomic sequence of Mycoplasma gallisepticum.
|
| Background |
Although
mycoplasmosis has been controlled with the current generation of vaccines,
future control programs may need to focus on improvements in these vaccines
so that they are compatible with eradication programs or so that they are
effective in different strains of bird. In the last few years a number
of human pathogens have been fully sequenced, including four human mycoplasmas,
and parallel information for avian mycoplasmas would enable rapid application
of findings on important human mycoplasma genes to improving avian mycoplasma
vaccines. |
| Research |
The
complete sequence of the genome of the virulent R strain of M. gallisepticum
was
determined. The genome was found to be 996,422 base pairs and was predicted
to contain 742 genes encoding proteins. Some function could be assigned
to 469 of these. A further 150 predicted genes are similar to genes in
other bacterial species and 123 are thus far unique to Mycoplasma gallisepticum.
A total of 80 genes are predicted to encode lipoproteins which are likely
to be involved intimately in interactions with the host and a number of
other putative virulence factors have been identified. |
| Outcomes |
These
data lay a strong basis for ongoing studies on the basis of virulence in
M.
gallispticum. Once the work has been published the data will be publicly
available at http://cevr.uconn.edu/. |
| Implications |
The
capacity to enhance protection against mycoplasmosis in poultry will be
enhanced by the use of these data to identify genes involved in virulence
and thus which may be suitable as targets for developing novel attenuated
vaccines. |
| Publications |
Papazisi, L., Gorton, T.S.,
Kutish, G., Markham, P.F., Browning, G.F., Nguyen, K.D., Swartzell, S.,
Madan, A., Mahairas, G. and Geary, S.J. (2003) The complete genome sequence
of the avian pathogen Mycoplasma gallisepticum strain Rlow.
Microbiology
(in press).
|
| Project
Title: |
Attenuation
and characterisation of chicken Eimeria for live vaccines |
| Project
No: |
DAQ-259J |
| Researcher: |
Dr.
Wayne Jorgensen and Dr. Glenn Anderson |
| Organisation: |
Department
of Primary Industries (Qld)
Animal Research Institute
Locked Mail Bag No 4
MOOROOKA QLD 4105 |
| Phone: |
(07)
3362 9455 |
| Fax: |
(07)
3362 9429 |
| Email: |
wayne.jorgensen@dpi.qld.gov.au |
| Objectives |
· To develop attenuated
lines of E. mitis, E. brunetti and E. praecox for incorporation
in an efficacious, live vaccine protective against all seven species of
Eimeria
in Australian chickens.
· To develop a trial
technique to evaluate coccidiostat resistance.
|
| Background |
Coccidiosis
is one of the more economically important disease problems in Australia’s
intensive poultry industries. Control of the disease is based on the use
of chemicals and drugs that cost the poultry industries more than $10 million
pa. Vaccination, used alone or in combination with coccidiostats, is currently
the most sustainable avenue for control of coccidiosis. Live vaccines have
been available for a number of years in some countries, but until this
vaccine development work was initiated, similar vaccines had not been available
to the Australian industry. The benefits of using live coccidiosis vaccines
include long term, economical protection against disease, ability to manage
existing and developing chemical resistance, and provision of an alternative
to chemical control to minimise residue and withholding period problems.
Seven species of Eimeria can cause coccidiosis in poultry. The previous
two stages of this series of projects have been successfully completed
with the development and evaluation of vaccine strains of E. maxima,E.
acervulina, E. tenella and E. necatrix suitable for use in a
live poultry coccidiosis vaccine. Vaccine strains of the remaining three
species of Eimeria that can cause coccidiosis in poultry
(E. mitis, E. brunetti and E. praecox) therefore remained
to be developed to provide comprehensive cover against coccidiosis. |
| Research |
Vaccine
candidate strains of E. mitis, E. brunetti and E. praecox
were isolated from relatively small, non-commercial flocks that were not
regularly exposed to coccidiostats. The strains were purified by single
oocyst passage and demonstrated, in trials, to be susceptible to at least
two of the following coccidiostats at doses recommended by the manufacturer
- Sulphaquinoxaline, Toltrazuril or Amprolium. The Jorgensen strain of
E.
mitis was passaged for precocious development. The Bowden strain of
E.
brunetti and Jorgensen strain of E. praecox were not modified
for precocious development because low pathogenicity was demonstrated in
trials with the parent strains. Each of the three vaccine strains was demonstrated
to provide protection against challenge with two virulent field isolates.
A trial format for evaluating
resistance to the in-feed coccidiostats narasin and monensin was developed
and evaluated using Eimeriavax 4M (vaccine) and three field isolates. The
vaccine is susceptible to both coccidiostats based on decreased oocyst
output in treated groups. One field isolate, the Kelly strain of E.
praecox, was not susceptible to either coccidiostat. The trial
design appears suitable for detecting resistance to prophylactic coccidiostats. |
| Outcomes |
This
project has developed vaccine strains of E. mitis, E. praecox and
E.
brunetti and evaluated them for coccidiostat susceptibility, pathogenicity,
and protection against virulent field isolates. In all cases the strains
were demonstrated to be suitable for use as vaccine strains and have been
transferred to commercial partners, Eimeria Pty Ltd, for incorporation
into new custom vaccines. A trial design to test resistance to in-feed
(prophylactic) coccidiostats has been evaluated and demonstrated resistance
in field isolates. The trial format can be used by industry to monitor
developing coccidiostat resistance. |
| Implications |
The
final outcome of the three stages of the project series is the availability,
to the Australian poultry industry, of live precocious vaccines against
the seven species of Eimeria that cause poultry coccidiosis. Vaccination
is now being used routinely to protect flocks in the USA and some European
countries including Britain, and the availability of this new vaccine product
here in Australia will afford the Australian industry similar alternative
control possibilities. |
| Publications |
Anderson G.R. and Jorgensen
W.K. (2001) Development of Australian live vaccines against coccidiosis:
characterisation of attenuated lines using standardised trials. Proceedings
of the VIIIth International Coccidiosis Conference pp. 70.
Anderson, G.R. and Jorgensen,
W.K. (2002) A comparison of virulent and precocious coccidiosis vaccines.
Proceedingsof
the 7th WPSA Asia Pacific Federation Conference and 12th Australian
Poultry Convention pp. 103-105.
Anderson, G.R., Jeston, P.J.,
Blight G.W. and Jorgensen, W.K. (2003) Selection and characterisation of
two attenuated vaccine lines of Eimeria tenella in Australia. Australian
Veterinary Journal (submitted).
Jeston, P.J, Blight, G.W.,
Anderson, G.R., Molloy, G.B. and Jorgensen, W.K. (2001) Comparison of infectivity
of Eimeria tenella oocysts maintained at 4, 12 or 28° C for
up to 10 months. Australian Veterinary Journal 80: 74-75.
Jorgensen, W.K. and Anderson,
G.R. (2001) Development of Australian live vaccines against coccidiosis:
selection, isolation and attenuation. Proceedings of the VIIIth International
Coccidiosis Conference
pp. 101-102.
Lew, A.E, Anderson, G.R,
Minchin, C.M, Jeston, P.J. and Jorgensen, W.K. (2003) Inter- and intra-strain
variation in the internal transcribed spacer 1
(ITS-1) sequences of Australian
species and isolates of Eimeria from chickens. Veterinary Parasitology112:
33-50.
|
| Project
Title: |
Investigations
into the development of a sustainable management strategy for the darkling
beetle, Alphitobius diaperinus (Panzer) in Australian broiler houses |
| RIRDC
Project No.: |
DAQ-273A |
| Researcher: |
Mr.
Trevor Lambkin |
| Organisation: |
Department
of Primary Industries (Qld)
Entomology Building
Indooroopilly Research Centre
80 Meiers Road
INDOOROOPILLY QLD 4068 |
| Phone: |
(07)
3896 9434 |
| Fax: |
(07)
3896 9446 |
| Email: |
Trevor.Lambkin@dpi.qld.gov.au |
| Objectives |
· To investigate
sustainable management practices for the darkling beetle, Alphitobius
diaperinus
(Panzer), in broiler houses; these practices to be aimed
at reducing pest numbers, identifying current inefficiencies in insecticide
applications, developing novel control strategies, and providing sustainable
management of current registered insecticides and a better understanding
of pest population dynamics.
· To deliver an overall
reduction in associated poultry disease and insecticide use within the
broiler industry.
|
| Background |
A
long history of consistent applications of insecticides has proved inadequate
for the long-term control of A. diaperinus in Australian broiler
sheds. Earlier research has shown that resistance to the insecticide
fenitrothion is widespread in eastern Australian beetle populations
and, moreover, this research has indicated that the size of pest populations
in broiler houses often has no positive correlation to insecticide resistance.
Therefore, in 2000 this three year research project was initiated to determine
and quantify insecticide resistance in farm populations of A. diaperinus,
to study the bionomics of the pest, to determine the field efficacy of
another insecticide, cyfluthrin, and to investigate potential alternative
control strategies. |
| Research |
Insecticide
resistance to cyfluthrin in farm populations of A. diaperinus was
quantified and its efficacy in controlling beetle populations investigated.
The bionomics of the pest, including its spatial and temporal distributions
in a range of broiler house types, was studied. Diatomaceous earth was
investigated in the laboratory as a potential non-chemical litter treatment.
A field trial was completed to determine and compare the efficacy of floor
applications of cyfluthrin and SpinosadÒ on beetle numbers in the
litter and floor. A study tour to the USA was undertaken to hold discussions
with international scientists and observe A. diaperinus management
strategies in broiler houses. |
| Outcomes |
Insecticide
resistance to cyfluthrin in farm populations of A. diaperinus was
found to have developed over the last three years. Results showed that
the majority of beetles in broiler houses occur under feed pans in litter
and that conventional earth floor houses have the highest numbers of beetles
and concrete floor houses the least. Cyfluthrin was found to have little
efficacy in controlling A. diaperinus in the litter and in earth
floors of broiler houses. Spinosad® and diatomaceous earth
appeared to have some potential for beetle control. Management strategies
used for control of beetles in the USA were documented and anecdotal evidence
suggested that they are also inadequate.
The results from all investigations
undertaken corroborate well, and have identified that floor applications
of insecticides in broiler houses do little to control A. diaperinus
in the earth floors of the houses at the beginning of each batch, and
A diaperinus in the litter during the subsequent period of the batch.
This lack of control has been further exacerbated by the marked increase
in resistance to cyfluthrin (the industry standard insecticide) that has
been demonstrated to have occurred over the past three years in some populations
of A. diaperinus from southeast Queensland. |
| Implications |
The
results of this project indicate that a managed strategy for control of
this pest is needed. A suitable strategy for control of A. diaperinus
in earth floor broiler houses could be based on disinfestation of the earth
floor prior to placement of litter and the subsequent treatment of poultry
litter with a range of effective insecticide and non-insecticide litter
treatments. This strategy could possibly also require the application of
these treatments only to litter under feed pans. |
| Publications |
Lambkin, T.A. and Cameron,
M.C. (2000) Darkling beetle control in Australian broilers-A new direction.
Proceedings
of the 2000 Poultry Industry Exchange pp. 97-102.
Lambkin, T.A. and Cupitt,
D.A. (2002) Darkling beetle in Australian meat chickens-a better understanding.
Proceedings
of the 2002 Poultry Industry Exchange pp. 93-99.
Lambkin, T.A. and Cupitt,
D.A. (2002) Darkling beetle [Alphitobius diaperinus Panzer (Coleoptera:
Tenebrionidae)] control in Australian broilers-enhancing food safety. Proceedings
of the Fifty-First Western Poultry Disease Conference pp. 32-36.
|
| Project
Title: |
Postgraduate
scholarship – Ms Louise Hilton: Therapeutic applications of cytokines in
poultry |
| RIRDC
Project No.: |
CSA-10J |
| Researcher: |
Dr.
John Lowenthal and Ms. Louise Hilton |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GEELONG VIC 3220 |
| Phone: |
(03)
5227 5759 |
| Fax: |
(03)
5227 5531 |
| Email: |
john.lowenthal@csiro.au |
| Objectives |
· To enhance
disease resistance and vaccine efficacy in poultry by administration of
cytokine therapy.
|
| Background |
The
Australian poultry industries are reducing their usage of antibiotics and
other chemicals to control disease. To facilitate this process, safe natural
alternatives are being developed. The search for alternative strategies
has focused on the potential use of natural therapeutics. Cytokines are
proteins that are normally produced by the body’s immune system following
infection. Cytokines protect against disease by controlling the immune
response to infection or vaccination and therefore represent excellent,
naturally occurring therapeutics. One such cytokine, interleukin-2 (IL-2),
has been shown in mammals to play a major role in the induction of the
immune response and IL-2 has been studied widely as an immuno-therapeutic
due to its pleiotropic properties and pivotal role in initiating T cell
proliferation. The aim of this study was to characterise the biological
functions of chicken IL-2 (ChIL-2) as a prelude to its assessment as a
vaccine adjuvant or therapeutic agent. |
| Research |
The
focus of this project was to assess the potential of ChIL-2 as a therapeutic.
To examine the immunoenhancing capability of ChIL-2, recombinant protein
was expressed in several prokaryotic and eukaryotic expression systems
and its biological activity confirmed. Antibodies and enzyme-linked immunoassays
specific for ChIL-2 were developed to characterise its in vivo function,
in particular its effects on modulating T cell populations and enhancing
T cell activation following its administration to chickens. The effect
of ChIL-2 on growth promotion was also measured. |
| Outcomes |
Treatment
of birds with ChIL-2 protein resulted in both the activation (measured
by expression of cell surface IL-2 receptors) and proliferation (as measured
by DNA synthesis) of T cells. Injection of recombinant ChIL-2 protein increased
the proportion of CD4+ cells, CD8+ T cells and the
proportion of T cells expressing the ChIL-2 receptor in peripheral blood
within 48 h. The increase in T cell subsets was shown to be a result of
cell proliferation. These results suggest that treatment with ChIL-2 is
effective in modulating the immune response and may thereby enhance immunity
and protection against a variety of viral and parasitic diseases.
An initial trial showed that
treatment of broilers with ChIL-2 during the first week post-hatch resulted
in enhanced weight gain over a six week period of growth under commercial
conditions. ChIL-2 treatment increased the body weight of chickens (~4%)
and also increased the efficiency of feed utilization. |
| Implications |
The
implications of this work for the Australian poultry industry are significant.
The introduction of cytokines as therapeutics may in part compensate for
performance losses associated with the reduction in the use of antimicrobial
growth promotants and antibiotics for disease control. Cytokines offer
a two-pronged attack. They can strengthen and control immune responses
resulting in an increase in the general health of animals. Secondly, they
can improve the efficacy of vaccines, resulting in effective long term
protection against specific pathogens.
Having established this technology
and models, there is now an opportunity to assess other types of cytokines
that have different types of activities, for their therapeutic and immuno-enhancing
capability in poultry. |
| Publications |
Hilton, L.S., Bean, A.G.D.,
Kimpton, W.G. and Lowenthal, J.W. (2002) Interleukin-2 directly induces
activation and proliferation of chicken T cells in vivo.
Journal
of Interferon and Cytokine Research 22: 755-763.
Hilton, L.S., Bean, A.G.D.
and Lowenthal, J.W. (2002) The emerging role of avian cytokines as immunotherapeutics
and vaccine adjuvants. Veterinary Immunology and Immunopathology85:
119-128.
Jones, D.C. and Black, D.B.
(1999) Poultry vaccines currently available in Australia. Proceedings
of the 11th Australian Poultry Science Symposium 11: 222-225.
Smith, A.B., Jones, D.C.,
Brown, E. and Black, D.B. (1997) Viruses in the meat chicken industry in
south eastern Australia. Virology,
234: 667-676.
|
| Project
Title: |
Molecular
epidemiology of Newcastle disease in Australia |
| RIRDC
Project No.: |
CSA-11J |
| Researcher: |
Dr.
Allan Gould, Dr. Matthew Stevens, Mr. Paul Selleck and Ms. Jacqueline Kattenbelt |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GEELONG VIC 3220 |
| Phone: |
(03)
5227 5119 |
| Fax: |
(03)
5227 5555 |
| Email: |
allan.gould@csiro.au |
| Objectives |
· To characterise
Australian Newcastle disease viruses (NDVs) at the gene sequence level
in order to understand the types of viruses present and their potential
to cause a virulent Newcastle disease outbreak.
|
| Background |
Very
little was understood as to the range and inter-relationships of Newcastle
disease viruses (NDVs) in Australia at the molecular level prior to the
commencement of this research. It was assumed that only avirulent NDVs
were present in Australia and that these viruses did not cause disease
in poultry. The emergence of virulent NDV in NSW in 1998 demonstrated this
lack of knowledge and the causal reasons for the initial and subsequent
outbreaks of disease. |
| Research |
Phylogenetic
studies were done on outbreak NDV isolates and previously isolated NDVs
in Australia. The complete genomes of ten isolates of virulent and avirulent
viruses associated with the ND outbreaks that occurred between 1998 and
2002 were determined to provide a database for further research. The genetic
variability of the virulent locus within the virulent NDV isolates was
compared to other sites and genes within the NDV genome. These results
were used to understand the process whereby virulent viruses could emerge
from an avirulent background and were used to test several hypotheses regarding
their emergence. The ability of other avian viruses to alter the sequelae
of an NDV infection was also investigated. |
| Outcomes |
The
source of ND outbreaks from 1998-2002 was identified as being caused by
the natural mutation of a pre-existing avirulent Australian NDV strain.
The ability of this ‘progenitor’ virus and similar viruses to generate
virulent virus was quantified at the quasispecies level. A Real-Time PCR
was developed to detect virulent virus in a population of avirulent viruses.
The complete genome sequence of ten NDV isolates (associated with the 1998-2000
outbreaks of virulent NDV in NSW) have been determined. This has enabled
the genetic drift of the virus to be accurately determined and the confirmation
that there is an association of the progenitor virus with virulent NDV
outbreaks. Analysis of the individual viral sequences that constitute a
field isolate (quasi-species analysis) has shown that buried within the
avirulent progenitor virus population, virulent viruses may be hidden.
Analysis of other Australian NDV isolates revealed the presence of a clade
of viruses with the potential to cause virulent NDV outbreaks similar to
the Mangrove Mountain outbreak. |
| Implications |
The
cause of virulent NDV in Australia has been firmly linked to the presence
of viruses that are only a few nucleotides away from virulence. The source(s)
of this virus remain endemic within Australia and have the potential to
continue to mutate and act as a source of virulent virus outbreaks within
the poultry industry. Eradication of these viruses could be possible by
the use of a survey and vaccination campaign. |
| Publications |
Gould, A.R., Kattenbelt,
J.A. Selleck, P., Hansson, E., Della-Porta, A.J. and Westbury, H.A. (2001)
Virulent Newcastle disease in Australia: molecular epidemiological analysis
of viruses isolated prior to and during the outbreaks of 1998-2000. Virus
Research 77:
51-60.
|
| Project
Title: |
Diagnostic
tools for differentiation of vvIBDV and characterisation of local IBDV
strains |
| RIRDC
Project No.: |
CSA-15J |
| Researcher: |
Dr.
Jagoda Ignjatovic, Dr. Sandra Sapats and Mrs. Gaylene Gould |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GEELONG VIC 3220 |
| Phone: |
(03)
5227 5000 |
| Fax: |
(03)
5227 5555 |
| Email: |
Jagoda.Ignjatovic@csiro.au |
| Objectives |
· To develop ELISA
and RFLP for differentiation of vvIBDV strains.
· To demonstrate that
changes in local IBDV field isolates remain such that they can be clearly
differentiated from all overseas strains.
|
| Background |
Very
virulent infectious bursal disease virus (vvIBDV) is exotic to Australia.
A simple and rapid diagnostic test is needed in the event of an exotic
incursion. In an earlier RIRDC project, a potential reagent specific for
vvIBDV in ELISA was developed (CRAb88). Further evaluation of this reagent
was needed. Furthermore, the technique of restriction fragment length polymorphism
(RFLP) was developed in the USA for the differentiation of IBDV strains
and work undertaken by the US researchers who developed this technique
suggested that Australian strains were similar to vvIBDV strains. The usefulness
of this method for differentiation of Australian strains therefore also
required evaluation, and the US result for Australian strains needed to
be further investigated. It was also possible that vvIBDV-like strains
could emerge from local endemic strains and that monitoring of strains
circulating in commercial poultry flocks would provide an early warning
of the emergence of such strains. |
| Research |
The
specificity of CRAb88 was tested in two overseas laboratories against a
range of IBDV strains. The RFLP method was introduced into the research
team’s laboratory and tested with all Australian IBDV strains. IBDV field
isolates were obtained from various commercial poultry sites and their
antigenic and genetic properties compared to other strains. |
| Outcomes |
CRAb88
was shown to react only with vvIBDV, detecting all vvIBDV regardless of
their country of origin. An ELISA was subsequently developed and transferred
to the diagnostic section of CSIRO Livestock Industries’ laboratory. The
RFLP method was introduced, however by this method Australian IBDV strains
were shown to belong to 12 different groups which differed from the 47
other groups identified amongst overseas strains. Thus, RFLP is not suitable
for simple and meaningful strain differentiation in Australia. No similarity
between Australian and vvIBDV was detected by this method. Seven new IBDV
isolates collected from broiler sites between 2001 and 2003 were found
to be antigenically and genetically similar to other earlier Australian
IBDV strains. |
| Implications |
A
simple and fast diagnostic test (ELISA) is now available in Australia for
the differential diagnosis of exotic vvIBDV incursion. Monitoring of local
IBDV strains showed no major changes have occurred in either their antigenicity
or virulence. |
| Publications |
Sapats, S. and Ignjatovic,
J. (2002) Restriction fragment length polymorphism analysis of the VP2
gene of Australian strains of infectious bursal disease virus. Avian
Pathology 31: 559-566.
Ignjatovic, J. and Sapats,
S. (2002) Characterisation of additional infectious bursal disease virus
field isolates confirms existence of two distinct genetic groups in Australia.
Australian
Veterinary Journal
80: 689-694.
Sapats, S.I., Heine,H.G.,
Trinidad, L., Gould, G.J., Foord, A.J., Doolan, S.G., Prowse, S. and Ignjatovic,
J. (2003) Generation of chicken monoclonal antibody fragments that differentiate
and neutralise infectious bursal disease virus (IBDV). Archives of Virology
148:
497-515.
|
| Project
Title: |
Biological
control of necrotic enteritis in meat chickens |
| RIRDC
Project No.: |
CSA-12A |
| Researcher: |
Dr.
Robert Moore |
| Organisation: |
CSIRO
Livestock Industries
Private Bag 24
GEELONG VIC 3220 |
| Phone: |
(03)
5227 5760 |
| Fax: |
(03)
5227 5555 |
| Email: |
rob.moore@csiro.au |
| Objectives |
· To control necrotic
enteritis in broiler chickens using a cost effective, user-friendly, environmentally
sustainable biological control strategy.
|
| Background |
There
is increasing pressure on the intensive animal production industries to
decrease the use of antibiotics. Therefore, within the broiler chicken
industry there is a need to develop alternative methods to control disease
and maintain productivity. RIRDC have identified necrotic enteritis as
a specific threat that needs to be addressed. |
| Research |
The
research was aimed at developing antimicrobial peptides (bacteriocins),
with activity against Clostridium perfringens, as products that
could be used to protect chickens from the clinical manifestations and
production losses caused by necrotic enteritis. The strategy was to clone
and express synthetic bacteriocin genes and deliver the encoded recombinant
proteins to the site of infection (the gut) in chickens. To test the products,
a necrotic enteritis disease model needed to be established. |
| Outcomes |
Eight
bacteriocin and two defensin genes were designed, synthesised, cloned,
and expressed. Five of the recombinant bacteriocins were shown to have
biological activity with three of them having activity against C. perfringens.
The expressed bacteriocins were demonstrated to be safe in chickens and
mice. A wide range of conditions was investigated in order to establish
a necrotic enteritis model and eventually disease induction was possible.
Unfortunately the model was developed too late in the project to test the
products. In the meantime, the products were tested in other disease models
and were shown to be effective in controlling a Listeria monocytogenes
infection in the gut of chickens. |
| Implications |
The
bacteriocins showed promise in controlling an infection in chickens and
now must be tested and further developed for application against necrotic
enteritis. |
| Publications |
Ingham, A., Ford, M., Moore,
R.J. and Tizard, M. (2003) The bacteriocin piscicolin 126 retains antilisterial
activity in vivo.
J. Antimicrob. Chemother. 51: 1365-1371.
Ingham, A., Sproat, K., Tizard,
M. and Moore, R.J. (2003) An optimised method and plasmid vectors for expression
of non-modified bacteriocins in Escherichia coli. Submitted to J.
Appl. Microbiol.
Ingham, A., Sproat, K., Tizard,
M. and Moore, R. (2001) Recombinant antimicrobial peptides active against
veterinary pathogens.
Microbiology Australia 22: 25.5.
Ingham, A., Sproat, K., Tizard,
M., and Moore, R. (2002) Recombinant antimicrobial peptides – bacterial
missiles. Microbiology Australia 23: 3.3.
|
| Project
Title: |
Canola
meal and cottonseed meal in broiler and layer diets |
| RIRDC
Project No.: |
DAQ-264J |
| Researcher: |
Dr.
Rider Perez-Maldonado |
| Organisation: |
Department
of Primary Industries (Qld)
QPRDC
PO Box 327
CLEVELAND QLD 4163 |
| Phone: |
(07)
3824 3081 |
| Fax: |
(07)
3824 4316 |
| Email: |
Rider.Perez@dpi.qld.gov.au |
| Objectives |
· To provide information
on the chemical composition and variability with processing of Australian
canola meals and cottonseed meals at practical inclusion levels for use
in broiler and layer diets.
· To provide recommendations
to the poultry industries on the nutritional value of both canola and cottonseed
meals when included in least-cost diets at levels close to the upper limit.
|
| Background |
Although
canola meal (CM) and cottonseed meal (CSM) offer great potential in the
poultry industry they are used at low levels (4-10%) in diets because of
the presence of anti-nutritive factors (ANF) and variation in nutritional
value due to location, environmental factors, cultivars, and processing.
In Australia, the content of some ANF in CSM and CM have been reduced by
genetic selection and by pre-press solvent extraction. Addition of soluble
iron salts to diets reduces the negative effects of gossypol in CSM. New
strains of laying birds and broiler chickens, improved canola and cotton
varieties and better procedures for oil extraction from these crops provide
new requirements and opportunities for the investigation of the suitability
and nutritional value of these ingredients for poultry diets.
In
particular, there is potential for higher inclusion levels (>10%) above
those normally used in practice for CSM and CM in poultry diets. |
| Research |
Four
broiler trials and six layer trials were conducted using
CSM and CM from various processors in Australia that were sampled over
three years at the end of each processing cycle. These experiments evaluated
CM and CSM obtained from processing plants located in NSW, Queensland,
Victoria and WA. Broiler experiments were conducted over starter (0-21
days old) and finisher (21-42 days old) periods and evaluated chicken performance
and health status. Layer trials lasted over 14 to 16 weeks and evaluated
bird production performance and egg quality. |
| Outcomes |
Amino
acid (AA) digestibility between CSM sources varied little and was consistent
across samples. When compared with extruded meals, solvent extracted CSM
showed an overall improved AME in both broiler and layer diets and contained
low gossypol, condensed tannins and fibre levels, which are mostly removed
during processing. The chemical composition within CM varied little across
evaluations. However, between CM sources, chemical profile variation was
common, particularly between solvent extracted and extruded meals. The
overall AA digestibility across samples from different sources was satisfactory.
Variations between solvent and extruded meals, particularly on lysine digestibility,
were apparent. Glucosinolate levels among Australians CM were approximately
one third of those found in Canadian "double zero" varieties. Sinapine
content ranged from 11-15 g/kg, with extruded meals having the highest
values. Seasonal, environmental and plant processing conditions accounted
for most of the variation found in CSM and CM from different processors.
For broilers, the overall results indicated that during the starter period,
200 g CSM/kg supported satisfactory performance. However, during the finisher
period up to 300 g CSM/kg gave satisfactory performance, reducing abdominal
fat pad without affecting chicken health. During the starter period, chicks
fed on CM did well at 200 and 300 g CM/kg, depending upon CM source. During
the finisher period, up to 300 g CM/kg gave the best results, reducing
abdominal fat pad and intestinal viscosity without affecting chicken health
status.
In layer experiments, CM
and CSM fed at various levels (100, 120, 150 or 200 g/kg) resulted in satisfactory
performance in both brown and white strains of birds. Isabrown birds were
more efficient when compared with White Supertint, birds, which gave higher
egg weights and thus similar egg mass. The effect of gossypol or cyclopropenoid
fatty acids (CPFA) levels in the CSM diets did not affect egg production.
The addition of ferrous sulphate at the ratio 2:1 (ferrous sulphate to
gossypol) did not affect egg production in this study. Egg quality studies
on fresh eggs from brown layers fed on CM (100, 150, and 200 g/kg) indicated
the production of ‘fishy’ tainted eggs at 150 and 200 g/kg level without
any effect on yolk colour. ‘Fishy’ odour was not detected from eggs derived
from White Supertint birds. On CSM, brown discolourationon the yolk was
not observed in all evaluated eggs indicating that CSM from Narrabri is
derived from low gossypol varieties. Mottling effect on eggs was only observed
from brown and white layers fed CSM at 200 g CSM/kg. Cooked eggs from brown
hens had a significantly higher level of ‘prawny’ odour than eggs from
white birds. |
| Implications |
It
is recommended that each feed manufacturer determine the chemical composition
of CM and CSM ingredients before formulating poultry diets. Satisfactory
bird performance is possible when feeding high levels of CSM and CM provided
diets are formulated on a digestible AA basis. Coefficient tables provided
in this report could be used for formulating these types of diets. An important
consideration in using CSM in poultry diets is its low lysine (range 0.45-0.56)
and threonine (0.57-0.68) digestibility coefficient values which can be
overcome by adding synthetic amino acids to diets. Addition of iron salts
is highly recommended when formulating diets with upper levels of CSM to
overcome any residual gossypol effect. Therefore, with broilers 200 g CSM/kg
or 200 g CM/kg can be used during the starter period and 300 g/kg of either
CSM or CM can be used during the finisher period in diets formulated on
a digestible amino acid basis.
In layer hens, CM supported
satisfactory egg production and egg quality in White Supertint birds when
fed at 100, 150 and 200 g/kg levels. In brown birds, not more than 100
g CM/kg could be added without risking ‘fishy’ taint in eggs. Because the
lipid content of CSM tended to produce mottling, it is advised to use only
solvent extracted, low residual oil CSM at 150 g/kg maximum in white or
brown laying hen diets. |
| Publications |
Trappett, P.C., Barram,
K.M., Kemsley, M.K. and Perez-Maldonado, R.A. (2001) Evaluation of low
glucosinolates canola meals on production and performance of laying hens.
Proceed.
Aust. Poult. Sc. Symp. 13: 247.
Perez-Maldonado, R.A., Blight,
G.W. and Pos, J. (2001) Upper limits of inclusion of canola meal and cottonseed
meal in diets formulated on a digestible amino acid basis for broiler chickens.
Proceed.
Aust. Poult. Sc. Symp. 13: 156.
Perez-Maldonado, R.A. (2001)
Upper limits of inclusion of canola meal and cottonseed meal formulated
on a digestible amino acid basis for chicken meat production. Proceed.
Nut. Soc. Aust. 25: S33.
Bell, G.E., Nottingham, S.M.
and Perez-Maldonado, R.A. (2002) Sensory evaluation of eggs from
hens fed on canola meal and cottonseed meal based diets. Proceed.
Aust. Poult. Sc. Symp. 14: 100.
Perez-Maldonado, R.A.,Barram,
K.M. and Kemsley, M.F. (2002) Maximum inclusion of canola meal in broiler
starter diets formulated on a digestible and total amino acid basis.
Proceed.
Aust. Poult. Sc. Symp. 14: 180.
Perez-Maldonado, R.A.,Barram,
K.M., Trappett, P.C. and Kerven, G.L. (2002) Maximum inclusion of canola
meal in broiler finisher diets formulated on a digestible and total amino
acid basis.
Proceed. Aust. Poult. Sc. Symp. 14: 181.
Perez-Maldonado, R.A. and
Barram, K.M. (2003) Broiler performance in a semi-commercial environment
using diets containing upper levels of canola or cottonseed meals.Proceed.
Aust. Poult. Sc. Symp. 15: 177.
|
| Project
Title: |
Salmonella
typing and colonisation of chickens by characterised Salmonella Sofia |
| RIRDC
Project No.: |
IMV-3A |
| Researcher: |
Dr.
Michael Heuzenroeder |
| Organisation: |
Institute
of Medical and Veterinary Science
Infectious Diseases Laboratories
PO Box 14 Rundle Mall
ADELAIDE SA 5000 |
| Phone: |
(08)
8222 3275 |
| Fax: |
(08)
8222 3543 |
| Email: |
heuzenroeder@imvs.sa.gov.au |
| Objectives |
· To continue to
provide industry with a conventional and, where appropriate, molecular
based, Salmonella typing service.
· To test the feasibility
of AFLP typing as an epidemiological tool to replace PFGE as the preferred
molecular typing method.
· To characterise
by DNA sequence analysis the temperate (lysogenic) phage found in S.
Typhimurium phage type 64, which is a
common phage type found
in chickens and humans.
· To investigate Sofia
MH76 colonisation of chickens using different methods of inoculation and
S.
Typhimurium challenge.
|
| Background |
In
previous projects molecular typing methods for Salmonella were instituted
in conjunction with classical typing methods (serotyping and
phage typing) since they
can offer greater discriminating power for determining distribution and
location of potential pathogens. There are
newer techniques such as AFLP that have the potential to be superior to
the classical techniques and current molecular methods (such as PFGE)
that need to be investigated as they may be faster and provide more discriminatory
power.
One of the reasons why certain
strains predominate may be the carriage of bacterial viruses, also known
as bacteriophages or phages. ST64T and ST64B are two phages found
in S. Typhimurium DT64. It is possible that these phages can carry
genes that influence disease potential and strain distribution in
Salmonella
and therefore knowledge of the DNA sequences of the phages may be helpful
in determining whether virulence or other genes influence strain distribution.
For over two decades, S.
Sofia has been the major
Salmonella isolated from chickens but it
is almost never isolated from humans, therefore it has been suggested that
it could be acting as a natural competitive exclusion agent, excluding
pathogenic Salmonella strains such as S. Typhimurium DT64.
Further investigation of this possibility may help to explain why Sofia
is the predominant serotype found in chickens but doesn’t appear to be
pathogenic for humans and may provide new opportunities for reducing the
carriage of more pathogenic strains of Salmonella on chicken products. |
| Research |
AFLP
was established in the laboratory using commercial bacterial fingerprinting
kits. This technique was tested on S. Sofia isolates from over a
30 year period to establish whether unique Australian clones exist in order
to assess the discriminatory power of the technique in comparison with
PFGE. The DNA sequence was determined for the genomes of the ST64T and
ST64B phages. The number of genes contained within the phage genomes was
determined. The putative gene products (proteins) produced by the phages
were compared to the Genbank database to assign functions to the proteins.
This was done to determine whether any of these proteins might be involved
in virulence or influence current typing methods such as phage typing and
serotyping. Research was also carried out to determine whether S.
Sofia mutants (in the agf fimbrial gene) were disadvantaged in colonisation
of chickens, however, no differences were observed. As previous experiments
had failed to demonstrate that prior infection with S. Sofia had
any significant effect on subsequent colonisation by S. Typhimurium,
earlier exposure time of the chickens to S. Sofia was also investigated
to determine whether this might influence
co-colonisation with S.
Typhimurium. |
| Outcomes |
AFLP
typing was established to complement existing typing methods available
in this laboratory for the monitoring of Salmonella in chicken flocks.
It showed that no unique Australian clone of S. Sofia exists and
thereby demonstrated that there are no obvious genetic differences that
could explain the Australian situation with respect to S. Sofia.
The DNA sequences of ST64T
and ST64B were determined. It was found that ST64T could mediate genetic
exchange between bacteria. ST64B, which was widespread in many S.
Typhimurium strains, was defective and carried incomplete virulence factor
genes. Both phages could potentially influence typing results and have
the ability to acquire virulence factor genes. This data indicated a potential
to influence S. Typhimurium virulence and strain distribution.
Studies undertaken confirmed
that S. Sofia MH76 did not prevent co-colonisation with S.
Typhimurium in chickens. |
| Implications |
AFLP
was found to be a useful typing tool but will not replace other established
methods for typing, although in some cases it is clearly superior to established
methods and should be retained. A molecular phage-typing scheme can be
developed using genomic data gathered in this project. It is felt that
additional work on S. Sofia was unlikely to demonstrate a significant
potential for its use in displacing more pathogenic strains from the chicken
production environment, and it is therefore felt that no further work in
this is warranted. |
| Publications |
Mmolawa,
P.T., Schmieger, H., Tucker, C.P. and Heuzenroeder, M.W. (2003) Genomic
Structure of the Salmonella enterica Serovar Typhimurium DT 64
Bacteriophage ST64T: Evidence
for Modular Genetic Architecture. J. Bacteriol.
85: 3473-3475.
Mmolawa, P.T., Willmore,
R., Thomas, C.J. and Heuzenroeder, M.W. (2002) Temperate phages
in Salmonella enterica serovar Typhimurium: implications for epidemiology.
Int.
J. Med. Microbiol. 291: 633-644. |
| Project
Title: |
Development
of campylobacter bio-replacement program and establishment of campylobacter
reference laboratory |
| RIRDC
Project No.: |
UG-3A |
| Researcher: |
Dr.
Victoria Korolik and Prof. Peter Coloe |
| Organisation: |
Griffith
University
Microbial Glycobiology,
Institute for Glycomics
PO Box 50
Gold Coast Mail Centre
GOLD COAST QLD 9726 |
| Phone: |
(07)
5552 8321 |
| Fax: |
(07)
5552 8908 |
| Email: |
v.korolik@griffith.edu.au |
| Objectives |
· To evaluate and
refine the model system for colonisation of chickens with selected Campylobacter
strains.
· To evaluate highly
colonising and potentially non-virulent strains as potential ‘bio-replacement’
strains for application in the chicken industry.
· To provide a Campylobacter
reference laboratory based on molecular technology for identification of
virulent and non-virulent campylobacters, which can be used for epidemiological
tracing of specific strains.
|
| Background |
Campylobacter
spp are now the most common cause of human enteritis worldwide and it is
well established that chicken meat is one of the major sources of human
infection. It is therefore essential that the risk of transfer of Campylobacter
spp to humans via chicken meat is minimised. Since Campylobacter spp can
infect a high proportion of chicken flocks and intensive biosecurity programs
around the world have failed to stop colonisation of commercial flocks
by campylobacters, an alternative approach to control of Campylobacter
spp in chicken flocks is required. A possible alternative approach is to
use an avirulent strain of C. jejuni, which has been fully characterised,
to establish continuing colonisation in chickens and to displace other
strains which may be of more significance in a food safety context. |
| Research |
C.
jejuni strains were assessed in terms of their colonisation type by inoculating
two day old chicks with various strains of C. jejuni and assessing maximal
colonisation levels by quantitating the bacterial numbers in the caeca
of each chicken. Strains were also tested for their ability to out-compete
other colonising strains by inoculating different strains into chickens
already colonised with a different C. jejuni strain.
An alternative methodology
for control of pathogenic campylobacters in poultry by ‘bio-replacement’
was investigated and a potential bio-replacement strain was characterised
for its ability to colonise chickens already colonised with other C. jejuni
strains. This strain was also evaluated for its ability to sustain colonisation
in the face of challenge with other strains, using the two day old chicken
infection model developed previously. This strain was also tested for carriage
of possible virulence factors using toxicity assays, invasion assays in
tissue culture and a new mouse infection model.
In addition, a PRC molecular
detection and characterisation methodology for campylobacters was developed
using DNA sequences from ribosomal RNA and surface antigen genes. |
| Outcomes |
Five
different colonisation types were identified among C. jejuni strains.
These were (1) immediate colonisation with prolonged excretion of viable
C.
jejuni bacteria; (2) delayed colonisation with prolonged excretion
of viable C. jejuni; (3) immediate colonisation and slowly clearing
excretion; (4) delayed colonisation and slowly clearing excretion; and
(5) no colonisation of the intestines with C. jejuni bacteria. Infection
with strains of colonisation types 1 and 2 led to sustained colonisation
of the intestines of chickens.
Small experimental chicken
flocks were exposed to different
C. jejuni strains and within three
weeks one or two strains had replaced all others in the gastrointestinal
tract of the chickens. One such strain, C. jejuni strain 331, was
shown to be a super-efficient coloniser of chickens, non-invasive in tissue
culture, able to displace other strains present in the chicken intestine
and not displaceable by other Campylobacter strains tested. This
strain could potentially be used in a ‘bio-replacement’ program aimed at
preventing the colonisation by pathogenic campylobacters of chickens destined
for human consumption.
A multiplex PCR of C.
jejuni genomic DNA was developed to yield a PCR product with a unique
polymorphic site that could be used to quickly and accurately identify
and group C. jejuni isolates from purified DNA, cell culture, skin
washings and faecal samples. This formed the basis for campylobacter reference
laboratories now established at Griffith and RMIT Universities. |
| Implications |
One
particular strain of C. jejuni has been identified and characterised
as being a highly efficient coloniser of chickens yet lacking the ability
to invade human cells in tissue culture or to produce toxins. A ‘bio-replacement’
program for control of Campylobacter in chicken flocks, based on
this strain, will be evaluated in planned future research.
Campylobacter reference centres
have been established at Griffith and RMIT Universities and are available
for identifying and typing isolates of Campylobacter submitted by
industry or in future epidemiological studies. |
| Publications |
Ringoir, D.D. and Korolik,
V. (2003) Differences in colonisation patterns of Campylobacter jejuni
strains and changes in colonisation potential after passage in vivo.
Veterinary
Microbiology92: 225-235.
Korolik, V., Friendship,
D.T., Peduru Hewa, T., Alfredson, D., Fry, B.N. and Coloe P.J. (2001)Specific
identification, grouping and differentiation of Campylobacterjejuni
among thermophilic campylobacters using multiplex PCR. Epidemiology
and Infection 127: 1-5.
Fry, B.N., Yuen-Yuen Chen,
S.F., Newell, D.G., Coloe, P.J. and Korolik, V. (2000) The galE
gene of Campylobacter jejuni is involved in LPS synthesis and virulence.
Infection
and Immunity 68: 2594-2601.
|
| Project
Title: |
Isolation
of genes responsible for Campylobacter jejuni colonisation of the
chicken intestinal tract |
| RIRDC
Project No.: |
UG-4A |
| Researcher: |
Dr.
Victoria Korolik and Ms. Danielle Ringoir |
| Organisation: |
Griffith
University
Microbial Glycobiology,
Institute for Glycomics
PO Box 50
Gold Coast Mail Centre
GOLD COAST QLD 9726 |
| Phone: |
(07)
5552 8321 |
| Fax: |
(07)
5552 8908 |
| Email: |
v.korolik@griffith.edu.au |
| Objectives |
· To isolate and
analyse specific genes which are involved in colonisation of the chicken
intestinal tract by C. jejuni.
· To develop a strain-specific
C.
jejuni probe for molecular identification of specific strains in culture
and field samples.
|
| Background |
Campylobacter
species are recognised as the most common cause of gastroenteritis in humans
world-wide. Campylobacter jejuni is responsible for 80% of these infections.
A significant source of infection is consumption of undercooked and contaminated
chicken meat. Birds and other animals are frequently colonised with C.
jejuni as part of their normal flora. Ability to colonise is important
in order for bacteria to maintain themselves and propagate in the host.
C. jejuni strain 331 was previously shown to be highly colonising in chickens
and non-invasive in human tissue culture cells, able to displace other
strains from chicken intestinal tract and, once established, not able to
be replaced by other Campylobacter strains. Genes that are present in a
colonising strain such as strain 331, but not in a non-colonising strain,
might be important for colonisation of the chicken intestinal tract and
thus need to identified and characterised. |
| Research |
Subtractive
hybridisation methods, designed for identifying minor genetic differences
in closely related organisms, were used to genetically compare a non-colonising
C.
jejuni strain and a colonising C. jejuni strain. Unique genes
that are present in the latter strain but are absent from the former strain
were isolated and cloned to generate a small, subtracted genomic library
of candidate genes. The genes isolated by this method were identified by
sequencing the cloned DNA fragments and then by comparing the sequences
with known gene databases. In addition, every strain carries several genomic
DNA sequences unique to that strain. The subtracted genomic library was
screened in order to identify genes unique to C. jejuni strain 331
by genomic hybridisation with C. jejuni 331 and 16 other randomly
chosen strains. A unique sequence would hybridise to strain331 and none
other. |
| Outcomes |
The
genomic comparison between colonising and non-colonising strains identified
genes from the lipooligosacharide locus, capsule locus, restriction modification
enzymes, methyl accepting chemotaxis signal transduction proteins, lipoproteins
and transport proteins. Genes in other organisms with similar functions
have been implicated in having a role in colonisation. The methyl accepting
chemotaxis signal transduction protein found in this procedure is specific
for colonising strains, which indicates that this protein is important
for colonisation of the chicken intestinal tract. First attempts are currently
underway to disrupt this gene in order to elucidate its role in colonisation.
In addition, four fragments which are specific for the colonising C.
jejuni strain 331were identified and their specificity confirmed by
screening against other C. jejuni strains. These fragments can be
used for future design of a PCR protocol to identify C. jejuni strain
331. |
| Implications |
Identification
of genes related to colonisation will lead to a better understanding of
the colonisation process of C .jejuni and to the identification
of strain specific sequences which will permit the development of tests
for the specific identification of C. jejuni strain 331, the strain
which is being developed as a candidate ‘bio-replacement’ agent in project
UG-3A. |
| Project
Title: |
Reduction
of dust emissions from broiler and caged layer sheds |
| RIRDC
Project No.: |
SAR-33J |
| Researcher: |
Mr.
Thomas Banhazi |
| Organisation: |
South
Australian Research and Development Institute
GPO Box 397
ADELAIDE SA 5001 |
| Phone: |
(08)
8303 7781 |
| Fax: |
(08)
8303 7689 |
| Email: |
Banhazi.thomas@saugov.sa.gov.au |
| Objectives |
· To determine the
major risk factors associated with increased concentrations of dust within,
and dust emissions from, naturally and mechanically ventilated poultry
houses.
· To develop strategies
that will reduce both interior dust levels and dust emissions from buildings,
resulting in more sustainable housing systems for egg and broiler production
in semi-urban and more densely settled areas and reduced OH&S risks
for staff.
|
| Background |
Dust
in poultry buildings is composed of a mixture of material, such as skin
cells, dried droppings, feathers, bedding debris, feed particles and a
diverse range of micro-organisms. Dust particles can transport other pollutants
like odour molecules, bacteria, endotoxins and viruses, and promote the
distribution of these agents within and between livestock buildings. In
order to reduce dust emissions from poultry buildings, factors influencing
internal dust concentrations need first to be studied and understood, and
dust concentration and emission reduction methods reported in the literature
evaluated. A range of environmental factors, such as lighting, humidity,
temperature and ventilation, have been demonstrated to have an influence
on dust concentrations in some studies, but there are often interactions
between these factors and animal-dependant variables. Different methods
for reducing airborne pollutants, such as the negative electrostatic space
charge system, ozonisation and water sprays, have been tested by various
research groups. However, overseas research suggests the most useful technique
currently available is the impregnation of bedding material with an oil
and water mixture. |
| Research |
The
concentrations of a range of airborne pollutants (total airborne bacteria,
inhalable and respirable dust) present in 26 poultry housing facilities
in South Australia were measured. Data was also collected on housing features
used in the facilities. The measurements of airborne pollutants were made
using standardised methods and instruments, which allowed reliable comparisons
to be made between different buildings and classes of animals. The data
collected identified the key housing factors associated with elevated concentrations
of the measured pollutants.
Two separate experiments
were conducted to assess a dust abatement technique for use within poultry
buildings and an emission reduction method utilising an innovative and
low-cost air-scraping system. |
| Outcomes |
The
results obtained in this study will assist development of strategies for
reducing the effects of poor air quality on poultry production, health
and welfare and meeting OH&S guidelines for the poultry industry. Specifically,
a number of key housing and management factors have been identified as
having a significant effect on air quality. Oil impregnation of bedding
material was identified as a promising technology that can be effectively
used for dust reduction in broiler sheds. The innovative and low-cost air-scraping
system developed by the research group is also a promising technology and
could potentially be used by producers to reduce the concentration of emitted
airborne particles from livestock buildings. However, the technology still
needs refinement before it can be commercialised. Shed cleaning practices
and the type of the shedding used were also identified to be important
factors (amongst other factors) influencing the concentration of dust in
poultry buildings. |
| Implications |
The
adoption of routine dust concentration and emission reduction strategies
in poultry buildings is an important objective because of the increasing
environmental and occupational health and safety requirements associated
with these industries. Oil impregnation of bedding and utilisation of air-scrapers
appear to be potentially useful methods for reducing the concentrations
and emissions of airborne particles. The implementation by industry of
appropriate shed cleaning practices and adoption of tunnel ventilated shedding
can also be expected to have significant benefits in terms of reducing
dust in and emitted from poultry sheds. |
| CSA-13J |
Postgraduate
scholarship - Jacqueline Kattenbelt: Analysis of virulence determinants
of Newcastle disease virus Refer to report page |
| CSA-20A |
Postgraduate
scholarship - Scott Sheedy: Live vectoring of therapeutic and prophylactic
proteins and pathogenesis in necrotic enteritis Refer to report page |
| CSA-21J |
Postgraduate
scholarship - Manija Asif: Cytokines and innate molecules for enhanced
mucosal immunity in the chicken Refer to report page |
| CSA-25J |
Postgraduate
scholarship - Kristie Jenkins: Improved therapeutics for Marek's disease
virus infection Refer to report page |
| MS023-03 |
Masters
in avian health - Dr Reza Fadavi Firooz |
| UTS-6A |
Postgraduate
scholarship - Ms Kelly Mai: The molecular basis for oocyst wall formation
in the apicomplexan parasite, Eimeria maxima Refer to report
page |
| UNE-86A |
Postgraduate
scholarship - Mr Nicholas Rodgers: Relationships between grain quality,
intestinal integrity, and performance of broiler chickens Refer to report
page |
| TA023-19 |
2003
Australian Poultry Science Symposium, February 2003 - funding for two invited
speakers |
| TA023-22 |
12th
International Conference Negative Strand Viruses 2003, Italy, June 2003
- Ms Jacqueline Kattenbelt |
| TA023-24 |
XIII
World Veterinary Poultry Congress, USA, July 2003 - Dr Trevor Bagust |
| TA023-25 |
XIII
World Veterinary Poultry Congress, USA and IBDV/CAV meeting, Italy, June
2003 - Dr Jagoda Ignjatovic |
| TA023-26 |
XIII
WVPA Congress, Denver, July 2003 - Dr Graham Burgess |
| WS001-07 |
Support
for the 12th Australian Poultry and Feed Convention/7th WPSA Asian Pacific
Federation Conference, Gold Coast, October 2002 |
| WS023-09 |
National
Biosecurity Workshops |
| Flock
Health |
| Project
Title |
Project
No |
Principal
Investigator |
Organisation |
Phone
No |
| Biological
control of necrotic enteritis in meat chickens |
CME03-01 |
Dr
Robert Moore |
CSIRO
Livestock Industries |
(03)
5227 5760 |
| New
diagnostic assays to improve control of coccidiosis in poultry |
CME03-13J |
Dr
Glenn Anderson |
Department
of Primary Industries (Qld) |
(07)
3362 9494 |
| Characterisation
and modulation of virulence of endemic IBDV strains using reverse genetics |
CME03-15J |
Dr
Jagoda Ignjatovic |
CSIRO
Livestock Industries |
(03)
5227 5769 |
| Diagnostic
tools for differentiation of vvIBDV and characterisation of Australian
strains |
CSA-15J |
Dr
Jagoda Ignjatovic |
CSIRO
Livestock Industries |
(03)
5227 5769 |
| The
effect of Newcastle disease vaccination with strain V4 on the course of
infections with the Peats Ridge strain of Newcastle disease virus |
CSA-18J |
Dr
Peter Daniels |
CSIRO
Livestock Industries |
(03)
5227 5272 |
| Postgraduate
scholarship - Scott Sheedy: Live vectoring of therapeutic and prophylactic
proteins and pathogenesis in necrotic enteritis |
CSA-20A |
Dr
Robert Moore |
CSIRO
Livestock Industries |
(03)
5227 5760 |
| Postgraduate
scholarship - Manija Asif: Cyto |
