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Rural Industries
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RIRDC Completed Projects in 2000-2001 & Research in Progress as at June 2001
To Chicken Meat Completed Projects
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* Indicates a joint chicken meat and egg program project. These projects will appear in both sections of this report.
Flock Health
Bird Nutrition and Feed Supply
Food Safety
| IMV-3A | Salmonella typing and colonisation of chickens by characterised S. Sofia |
| UG-3A | Development of campylobacter bio-replacement program and establishment of campylobacter reference centre |
Animal Welfare
| DAV-185A | Implementation of the RIRDC broiler welfare audit to industry |
Environmental Management
| JSC-1A | Sustainability improvements in the Victorian chicken meat industry (phase 1) |
| SAR-33J* | Reduction of dust emissions from broiler and caged layer sheds |
| Project Title | Detection of virulent strains of Newcastle disease virus in chickens previously infected with Australian strains of the virus |
| RIRDC Project No: | CSA-1J |
| Start Date: | 01/07/97 |
| Finish Date: | 30/06/01 |
| Researcher: | Dr Harvey Westbury |
| Organisation: | CSIRO
Livestock Industries
Private Bag 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5115 |
| Fax: | (03) 5227 5555 |
| Email: | harvey.westbury@dah.csiro.au |
Objective |
· To increase the speed, efficiency and confidence of detection of virulent strains of Newcastle disease virus (NDV) in flocks previously infected with endemic, lentogenic strains of the virus. |
Current Progress |
A conventional virus capture ELISA (vELISA) for Newcastle disease virus was developed using a specific polyclonal antiserum as the capture antibody and a mixture of three monoclonal antibodies as the detection system. Positive/negative levels in the test were assessed and the best target tissues in chickens infected with virulent strains of NDV determined. These were found to be bone marrow, spleen and kidney, though regular detection was also obtained from blood and lung samples. The vELISA was also able to detect virulent ND virus in the tissues of chickens immune to the disease following earlier immunisation with ND vaccine. Immune chickens were challenged with either the virulent Herts, Texas or Australian virulent ND virus strains. These virus strains could be detected in the tissues of immune chickens for up to 21 days after challenge, with most detection occurring between 4 and 10 days after challenge. The test was used on tissues of chickens naturally infected with virulent ND virus that were collected during the Australian epidemic. Results obtained from testing these samples were not as clear-cut as those obtained with tissues from experimentally infected chickens. The reasons for this difference are being examined. |
| Project Title | Postgraduate scholarship – Ms Louise Hilton: Therapeutic applications of cytokines in poultry |
| RIRDC Project No.: | CSA-10J |
| Start Date: | 06/06/99 |
| Finish Date: | 05/06/02 |
| Researcher: | Ms Louise Hilton and Dr John Lowenthal |
| Organisation: | CSIRO
Livestock Industries
Australian Animal Health Laboratory Private Bag 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5759 |
| Fax: | (03) 5227 5531 |
| Email: | john.lowenthal@li.csiro.au |
Objective |
· To enhance disease resistance and vaccine efficacy in poultry by administration of cytokine therapy. |
Current Progress |
Cytokines
are proteins that are naturally produced by the body’s immune system immediately
following an infection. Cytokines protect against disease by controlling
the immune response to infection or vaccination and therefore represent
excellent, naturally occurring therapeutics.
Previous poultry trials conducted by this research team have shown that treatment with a cytokine, interferon gamma, led to improvements in health and resulted in improved weight gains of the order of five to ten per cent. This cytokine also helped protect birds against coccidiosis infection. It is hoped that a range of therapeutics, using various types of cytokines, can be developed to provide producers with an alternative to in-feed antibiotics. This project has focused on the cytokine, chicken interleukin-2 (ChIL-2). Biologically active recombinant ChIL-2 was produced and its effects on the chicken immune system assessed. Tools were developed to investigate the activities of ChIL-2, including monoclonal antibodies which are used in an ELISA for measuring the level of this cytokine. ChIL-2 treatment of birds resulted in proliferation of both CD4+ and CD8+ populations of T cells. This effect indicated that ChIL-2 may be able to enhance cell mediated immunity, resulting in greater protection against a variety of viral and parasitic diseases. Currently, commercial trials are underway to study the ability of ChIL-2 to enhance vaccine efficacy in protection against infectious bronchitis virus and coccidiosis. |
| Project Title | Molecular epidemiology of Newcastle disease virus in Australia |
| RIRDC Project No: | CSA-11J |
| Start Date: | 01/06/99 |
| Finish Date: | 30/06/02 |
| Researcher: | Dr Allan Gould |
| Organisation: | CSIRO
Livestock Industries
Australian Animal Health Laboratory Private Bag 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5119 |
| Fax: | (03) 5227 5555 |
| Email: | allan.gould@dah.csiro.au |
Objectives |
·
To develop a better understanding of the epidemiology of Newcastle disease
virus (NDV) within Australia.
· To develop
a better understanding of the mutation rates as well as disease potential
of Australian NDV isolates at the molecular level.
|
Current Progress |
Investigation
of isolates associated with the outbreaks of Newcastle disease in NSW between
1998 and 2000 have shown that the progenitor virus for the outbreak arose,
not from and exotic incursion of virulent virus, but from mutation of an
avirulent, Australian precursor virus.
Gene sequence and phylogenetic analysis of Australian NDVs isolated from 1932 to 2001 has identified one locus as a predictor of viral lineage and the likely ancestor virus for the progenitor virus has been identified. Viruses involved in the summer respiratory disease syndrome have been identified as belonging to two separate clades and virulent virus has been isolated from both clades. The entire genomes of eight viruses from these outbreaks have been sequenced and the genetic stability of these isolates determined. Selection pressure has been shown to be greatest for the haemagglutinin-neuraminidase, matrix and phosphoprotein genes. Analysis of the quasi-species or individual gene sequences present (at a low frequency) in field isolates has shown that virulent viruses were present in a background of avirulent progenitor virus. Variants in the fusion protein cleavage site (which determines virus virulence) have been isolated and characterised. Quasi-species analysis of virulent and avirulent plaque purified viruses have shown that two to three passages in vivo or in vitro were needed to attain the same genetic diversity as that identified in field isolates. Studies of mechanisms for the natural selection of virulent viruses from field isolates have commenced. |
| Project Title | Biological control of necrotic enteritis in meat chickens |
| RIRDC Project No: | CSA-12A |
| Start Date: | 01/10/99 |
| Finish Date: | 30/09/02 |
| Researcher: | Dr Robert Moore |
| Organisation:
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CSIRO
Livestock Industries
Private Bag 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5760 |
| Fax: | (03) 5227 5790 |
| Email: | robert.moore@li.csiro.au |
Objective |
· To control necrotic enteritis in broiler chickens using a cost effective, user- friendly, environmentally sustainable, biological control strategy. |
Current Progress |
Significant progress has been made towards demonstrating that bacteriocins (naturally occurring bactericidal proteins) have the potential to be used in chickens to kill Clostridium perfringens, the causative agent of necrotic enteritis. A series of synthetic bacteriocin genes have been constructed and expressed in Escherichia coli. It has been demonstrated that the recombinant protein from four of these bacteriocins has killing activity against C. perfringens. Four trials in chickens aimed at developing a suitable disease model for necrotic enteritis, were conducted. Although some encouraging results have been obtained further work needs to be done to develop a consistent, useable model. As a prelude to testing in chickens, one of the recombinant bacteriocin proteins was used in a mouse/listeria disease model to demonstrate greater than 99% reduction in pathogen load following treatment. Large doses of the recombinant bacteriocin protein had no deleterious effect on mice, demonstrating the safety of the product. A range of different bacteria are being considered for use as live vectors to deliver the active bacteriocins to chickens and research undertaken has shown that good levels of expression of active recombinant bacteriocin can be achieved in some of these potential vector strains. |
| Project Title | Postgraduate Scholarship - Jacqueline Kattenbelt: Mapping of structure-function relationships of Newcastle Disease (ND) using reverse genetics |
| RIRDC Project No: | CSA-13J |
| Start Date: | 01/07/00 |
| Finish Date: | 30/06/03 |
| Researcher: | Ms Jacqueline Kattenbelt and Dr Allan Gould |
| Organisation: | CSIRO
Livestock Industries
Private Bag 24 GEELONG VIC 3213 |
| Phone: | (03) 5227 5119 |
| Fax: | (03) 5227 5555 |
| Email: | allan.gould@li.csiro.au |
Objectives |
·
To develop a viable DNA construct containing Newcastle disease virus (NDV)
genome and separate clones of NDV nucleocapsid, protein (N), phosphoprotein
(P) and polymerase (L).
· To establish a reverse genetics system to allow recovery of recombinant NDV. · To recover NDV mutants with substitutions in precise sites within the matrix protein to give strictly defined molecular mutants. · To map
structure-function relationships of viral proteins within infected cells
and to study viral morphogenesis, virulence factor and tissue trophism
determinants essential for NDV replication and infection using electron
microscopy.
|
Current Progress |
Long
overlapping fragments from the Peats Ridge NDV (precursor of the virulent
virus which was responsible for outbreaks of Newcastle disease (ND) in
Australia) have been generated and clones confirmed by polymerase chain
reaction (PCR) screening and sequencing. These fragments are currently
being joined at shared restriction sites to form a contiguous DNA fragment.
Separate clones of nucleocapsid protein (NP), phosphoprotein (P) and RNA directed RNA polymerase (L) have been generated and cloned into expression plasmids containing an internal ribosomal entry site allowing cap independent translation. The matrix (M) gene is currently in the process of being manipulated to insert unique restriction sites to enable the gene to be cut out and a modified M re-inserted. |
| Project Title | Diagnostic tools for differentiation of vvIBDV and characterisation of Australian strains |
| RIRDC Project No: | CSA-15J |
| Start Date: | 01/07/00 |
| Finish Date: | 30/06/03 |
| Researcher: | Dr Jagoda Ignjatovic |
| Organisation: | CSIRO
Livestock Industries
Private Bag No 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5769 |
| Fax: | (03) 5227 5555 |
| Email: | Jagoda.Ignjatovic@csiro.au |
Objectives |
·
To introduce and compare RFLP methods developed by other research groups.
· To test the specificity of Crab-88 and Crab-cos recombinant antibodies for very virulent infectious bursal disease virus (vvIBDV) · To compare
soluble, purified & phage expressed antibody for their suitability
as ELISA reagents.
|
Current Progress |
The
RFLP method was introduced and evaluated using the following overseas strains
available at AAHL: classical 52/70, 1/68 and APHIS, variants E and GLS,
and vvIBDV strains CS88 and Tasik. Restriction profiles generated
for each virus using restriction enzymes BstN1, MboI and SspI were identical
to those produced by the Jackwood and Sommer researchers who developed
this method. Australian strains used in the study of Jackwood were
obtained from the same source. The RFLP profile for these as well
as for all other Australian strains was obtained. None of Australian
strain contained an SspI site characteristic of vvIBDV strains.
The specificity of the antibody Crab88 for vvIBDV strains was tested in two overseas laboratories, France and the USA. Crab88 reacted only with vvIBDV strains and did not react with any of the other classical or variant strains, including ten vaccine strains. This indicates that Crab88 is specific for all vvIBDV strains. Two other recombinant antibodies reacted with all IBDV strains, including the USA variants. Crab88 expressed as phage and soluble antibody was evaluated for use in ELISA. Higher absorbances were obtained with phage than soluble antibodies. Reagents to produce phage antibodies were cheaper and ELISA based on phage antibodies was faster and simpler. |
| Project Title | Evaluation of fowlpox (FPV) strains free of reticuloendotheliosis virus (REV) as vaccines for use in Australian poultry flocks |
| RIRDC Project No: | CSA-16A |
| Start Date: | 01/04/00 |
| Finish Date: | 31/05/02 |
| Researcher: | Dr David Boyle |
| Organisation: | CSIRO
Livestock Industries
Australian Animal Health Laboratory Private Bag 24 GEELONG VIC 3220 |
| Phone: | (03) 5227 5018 |
| Fax: | (03) 5227 5555 |
| Email: | david.boyle@dah.csiro.au |
Objective |
· To undertake vaccine efficacy, safety and adventitious agent testing on reticuloendotheliosis (REV) free fowlpox virus (FPV) strains derived from S (Standard vaccine strain) and two field strains, FPV 59vac and FPV 62vac. |
Current Progress |
A commercial partner for this project has been identified and an agreement has been concluded. An appropriate technical staff member has been appointed and experimental work commenced in April 2001. The first vaccination and challenge experiment has been completed. This experiment has confirmed the REV-free status of the derived strains. From the challenge component of this experiment one of the strains has been identified as suitable for further development as a commercial vaccine candidate. Master seed and an experimental vaccine stock will be produced under production conditions for this strain prior to the conduct of safety and adventitious agent testing. These tests will be conducted as a preliminary to an application for a limited field evaluation of the strain. |
| Project Title | Infectious proventriculitis and stunting syndrome of broiler chickens |
| RIRDC Project No: | DAN-171A |
| Start Date: | 01/07/98 |
| Finish Date: | 30/09/01 |
| Researcher: | Dr Rod Reece |
| Organisation: | NSW
Department of Agriculture
Regional Veterinary Laboratory Elizabeth Macarthur Agricultural Institute PMB 8 CAMDEN NSW 2570 |
| Phone: | (02) 4640 6309 |
| Fax: | (02) 4640 6400 |
| Email: | rod.reece@agric.nsw.gov.au |
Objective |
· To understand the cause of infectious proventriculitis and stunting and to develop relevant control strategies. |
Current Progress |
A
few field cases of infectious proventriculitis were studied and conformed
to previous descriptions. Homogenate known to induce transmissible
proventriculitis was inoculated into a wide range of cell cultures, including
HRT-18 (human rectal tumour) and HD-10 (chicken macrophage) cell cultures,
and passaged. No cytopathic effects were noted and inoculated cell
cultures were negative for immunoreactivity using convalescent chicken
sera (inoculated with the same homogenate). Homogenate free of enveloped
virus by chloroform treatment and free of bacteria by filtration, was inoculated
into chicken embryos. The viscera of the embryos were harvested and
inoculated orally into chickens but proventriculitis was not induced.
Five electron-microscopic grids of transmissible proventriculitis were received from Athens, Georgia, USA, and hexagonal virus-like particles were readily observed in the nucleus and adjacent cytoplasm of proventricular alveolar epithelial cells of young chickens. At about the same time, electron-microscopic examination of proventriculi from our experimental cases at four days post-inoculation revealed similar particles. Similar particles were observed on examination of homogenate from one affected field case - this yielded reovirus on tissue culture. |
| Project Title | Attenuation and characterisation of chicken Eimeria for live vaccines |
| RIRDC Project No: | DAQ-259J |
| Start Date: | 01/11/99 |
| Finish Date: | 31/12/02 |
| Researcher: | Dr Wayne Jorgensen |
| 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: | jorgenw@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. |
Current Progress |
The
sensitivity of two strains of Eimeria mitis (Jorgensen and Kelly)
to the coccidiostats Toltrazuril, Amprolium or Sulphaquinoxaline has been
evaluated in trials. Both strains were sensitive to Toltrazuril and
Amprolium. Each has since undergone selection for precocious development
by passage (Jorgensen strain: 9 passages with a 20 hour drop in prepatent
period; Kelly strain: 13 passages with a 14 hour drop in prepatent period).
The Jorgensen strain was chosen for further characterisation studies and
has been successfully tested for virulence, reproductive potential and
protection against homologous challenge. A trial to assess the strain’s
protection against heterologous challenge was aborted early and has now
been repeated. The results of the new trial are now awaiting statistical
analysis. Both strains of
E. mitis have passed quality control and
DNA testing for purity.
The sensitivity of two strains of Eimeria brunetti (Monarto and Bowden) to the coccidiostats Toltrazuril, Amprolium or Sulphaquinoxaline has been evaluated in trials. Both strains were sensitive to Toltrazuril and Amprolium and are currently underging selection for precocious development by passage. The sensitivity of one strain of Eimeria praecox (Kelly) to the coccidiostats Toltrazuril, Amprolium or Sulphaquinoxaline has been evaluated in a trial. One potentially coccidiostat resistant isolate has been collected at Pitsworth, South East Queensland and cryopreserved for future study. |
| Project Title | Investigations into the development of a sustainable management strategy for the darkling beetle, Alphitobius diaperinus (Panzer) in broilers |
| RIRDC Project No: | DAQ-273A |
| Start Date: | 01/07/00 |
| Finish Date: | 31/07/03 |
| 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: | lambkint@dpi.qld.gov.au |
Objective |
·
To investigate sustainable management practices for the darkling beetle,
Alphitobius
diaperinus (Panzer), in broiler systems which will aim at reducing
pest numbers, identifying current inefficiencies in insecticide applications,
sustainedly managing currently registered insecticides, developing novel
control strategies and understanding better beetle population dynamics.
|
C urrent Progress |
Research
undertaken this last year has entailed the laboratory testing of ten east
coast broiler beetle populations for resistance to cyfluthrin (Tugon®)
and population dynamics and cyfluthrin efficacy studies of six south east
Queensland broiler farms.
Insecticide resistance test results show that mostly low levels of cyfluthrin resistance occur in beetle populations tested from Sydney, south east Queensland and the Atherton Tableland (ie less than 10% survival at the discriminating dose). Field studies of the spatial distribution of beetle populations in six clay-floored broiler sheds have found that almost all beetles that occur in the clay floors are confined to the brooder sections of the sheds. Furthermore, within the brooder sections, the majority of beetles are found under the feed pans and to a lesser extent under the drinking pans. Despite cyfluthrin showing good efficacy in laboratory tests, field studies indicate that it has no effect on beetles that harbour in the ground between clean-outs. These studies show that mortality of these beetle populations does not increase after application and that just as many live beetles occur after the application as before. In summary, results of research thus far indicate that despite many beetle populations still being susceptible to Tugon® it does little in controlling beetles that occur in clay floors. As well, if a more efficient compound is developed to treat floors it may be strategically applied to the areas only under the feed and drinking lines, which is where the majority of beetles occur. |
| Project Title | National NDV Survey |
| RIRDC Project No: | MS990-40 |
| Start Date: | 10/04/00 |
| Finish Date: | 31/07/01 |
| Researcher: | Dr Vivien Kite |
| Organisation: | Chicken
Meat Program of RIRDC
PO Box 579 NORTH SYDNEY NSW 2059 |
| Phone: | (02) 9929 4077 |
| Fax: | (02) 9925 0627 |
| Email: | vivien.kite@chicken.org.au |
Objectives |
·
To collect information on the type and distribution of Newcastle disease
viruses in Australian poultry flocks.
· To collect information on the sero-prevalaence of NDV positive flocks across the Australian commercial poultry indsutries and to identify risk factors for exposure to NDVs on Australian poultry farms. · To identify
possible risk factors for exposure to NDVs on Australian poultry farms.
|
Current Progress |
The
survey was designed to collect information on the sero-revalence of NDV
positive flocks across the Australian commercial poultry industries, to
identify possible risk factors for exposure to NDVs, and to collect information
on the type and distribution of NDVs in Australian poultry flocks.
The survey sampling strategy was designed to ensure comprehensive coverage of all sectors of the Australian commercial poultry industry. A total of 754 farms, across eleven regions of Australia, were sampled as part of the survey. Four types of commercial poultry enterprise were included in the survey viz. layer farms, meat chicken farms, breeder (meat and layer) farms, and dedicated pullet rearing farms. In each region, a minimum of 25% of layer farms (50% in NSW) and 30% of meat chicken farms represented in the region were included in the survey. All currently active breeder and pullet rearing farms in each region were included in the survey, except where the birds were too young. The survey was conducted in three phases. Initially, blood samples were collected and tested to establish the serological status of farms. Tracheal and cloacal swabs were then collected from seropositive farms for attempted virus isolation. Viruses isolated were genetically characterised (‘typed’), with typing based on nucleotide sequencing of the cleavage site of the gene that codes the fusion protein of NDV. A total of 259 confirmed NDV isolates were characterised, representing farms in Queensland, NSW, Victoria, Tasmania and South Australia. The majority of these isolates have come from Victorian farms. No virulent NDV isolates were detected. No precursor-like viruses (such as Peat’s Ridge or Somersby-type variants) were detected. All viruses detected have been V4-like viruses. Some minor genetic diversity was seen in these V4-like viruses, but all are genetically distinct from the virulent virus. A full analysis of the results of the survey is currently underway. |
| Project Title | The development of vaccination strategies to control necrotic enteritis in poultry |
| RIRDC Project No: | RMI-11A |
| Start Date: | 01/01/00 |
| Finish Date: | 31/05/02 |
| Researcher: | Prof Peter J Coloe |
| Organisation: | RMIT
University
Department of Biotechnology and Environmental Biology Bundoora West Campus Plenty Road BUNDOORA VIC 3083 |
| Phone: | (03) 9925 7104 |
| Fax: | (03) 9925 7110 |
| Email: | pcoloe@rmit.edu.au |
Objective |
· To develop an effective vaccine against necrotic enteritis and to evaluate the vaccine against a challenge model of the disease. This vaccine will be orally deliverable, cost effective to manufacture and deliverable within established farming practices. |
Current Progress |
Three
trials have been completed with moderate success. Visible lesions were
produced, consistent with necrotic enteritis, in the jejunum and ileum
of birds. At post mortem, tissue from birds were given a score ranging
from 0-4; 0 for no change and 4 for major tissue damage. Over the
three trials the percentage of birds having a score greater than 1 from
a challenge with Cl. perfringens strain 61 was:
Trial 1
79%
Fifty histological sections of the jejunum and ileum from challenged birds have been prepared, stained with haematoxylin and eosin and are currently being read. Some of the histological data collected from these birds suggest that challenge with Cl. perfringens may not always result in necrotic tissue manifesting as visible lesions. There may be more subtle changes of the gut that will only be detected from histological examination. The main objective for the next six months is to improve the current protocol to obtain a consistently reproducible model. To do this, the following parameters from the current protocol will be changed: diet and age of infection. A formalin-killed whole-cell Cl. perfringens vaccine will be tested on the current chicken model and assess its effectiveness in reducing mortality, severity of lesions and histological changes. |
| Project Title | Determination of the genomic sequence of Mycoplasma gallisepticum |
| RIRDC Project No: | UM-45J |
| Start Date: | 01/06/99 |
| Finish Date: | 15/06/01 |
| Researcher: | Dr Glenn Browning |
| Organisation: | The
University of Melbourne
Veterinary Preclinical Centre PARKVILLE VIC 3052 |
| Phone: | (03) 8344 7342 |
| Fax: | (03) 8344 7374 |
| Email: | glenfb@unimelb.edu.au |
Objectives |
·
To determine the complete genomic sequence of Mycoplasma gallisepticum.
· To facilitate identification of genes which are likely to play a role in virulence. · To lay a foundation for subsequent studies to improve the performance of mycoplasma vaccines and to improve diagnosis of mycoplasmosis. |
Current Progress |
A
library of clones has been constructed for sequencing. Draft coverage
of the genome, with an estimated three fold redundancy, has been obtained
to date. Although this data has been useful it is not in a form that can
be dispersed yet, as it comprises numerous small contigs.
A few gaps will remain to be closed after the completion of the random cloning phase and that is expected to take another several months to complete. The annotation will begin after that time. |
| Project Title | Avian Leukosis-J (ALV-J) in Australia: laboratory technologies and research needs |
| RIRDC Project No: | UM-49A |
| Start Date: | 01/03/01 |
| Finish Date: | 31/07/03 |
| Researcher: | Dr Trevor Bagust |
| Organisation: | The
University of Melbourne
Faculty of Veterinary Science, Pre-Clinical Centre Cnr Park Drive & Flemington Road PARKVILLE VIC 3052 |
| Phone: | (03) 9344 9676 |
| Fax: | (03) 9344 9675 |
| Email: | trevorjb@unimelb.edu.au |
Objective |
· To develop the most appropriate laboratory technologies and reagents for detection of avian leukosis subgroup J (ALV-J) and its associated disease effects for Australia's chicken meat industry. |
urrent Progress |
Over
100 field samples have been screened for the presence of ALV-J. Such
samples include vaginal swabs, whole blood and tumour tissues. Avian
leukosis virus has been isolated from four tumour samples representing
four different broiler breeders placed in two separate poultry operations.
One additional isolate was obtained from a second Australian laboratory,
where ALV-J was isolated from tumours detected in broiler breeders.
The current number of ALV-J isolates being studied in our laboratory amounts
to five.
Identification of ALV-J has been confirmed for all five viruses using molecular-based methods. Two different sets of polymerase chain reaction (PCR) oligonucleotide primers have been used for molecular identification of ALV-J directly from tumour tissue and from infected cells (secondary chicken embryo fibroblasts) in culture. One of the PCR primer sets amplifies specifically part of the polymerase/integrase and envelope genes. The second PCR primer set amplifies specifically part of the integrase gene, the entire envelope gene, various genetic sequences located downstream of the envelope gene, and part of the 3’ long terminal repeat (3’LTR). Virus stocks have been prepared for all five ALV-J isolates, and each of the stocks is in the process of being titrated. These stocks will be used for in vivo assays and for the production of polyclonal antiserum to be used for serological assays. Sequencing of the entire envelope gene and of the 3’ untranslated region (3’UTR) is under way and the data will be used for phylogenetic comparisons of Australian isolates against published genetic sequences of foreign isolates. The sequence information will also be used to optimise molecular-based diagnostic assays. |
| Project Title | Control of intestinal spirochaete infections in chickens |
| RIRDC Project No: | UMU-23J |
| Start Date: | 01/06/99 |
| Finish Date: | 30/08/01 |
| Researcher: | Prof David Hampson |
| Organisation: | Murdoch
University
Division of Veterinary and Biomedical Sciences MURDOCH WA 6150 |
| Phone: | (08) 9360 2287 |
| Fax: | (08) 9310 4144 |
| Email: | hampson@numbat.murdoch.edu.au |
Objective |
· To identify new and appropriate means to control infection by the intestinal spirochaetes, Brachyspira intermedia and Brachyspira pilosicoli, recently recognised and common pathogens causing significant economic loss in Australia layer and broiler breeder flocks. |
Current Progress |
Studies
have been conducted to determine in vitro antimicrobial drug sensitivities
of spirochaete isolates from Australian chickens, and to test in vivo
antimicrobial activity in experimentally infected layer and broiler breeder
birds.
Testing of 66 spirochaete strains revealed a similar spectrum of sensitivity to antimicrobial drugs as porcine spirochaetes. Resistance was seen against a number of drugs, with the least resistance recorded for tiamulin. In vivo, tiamulin at 25mg/kg body weight cleared experimental infection with Brachyspira intermedia in layer hens. Birds in an infected room, however, became re-infected after treatment ceased. This suggests that it may be better to use continual low level therapy to control these infections, or to use therapeutic levels of drugs combined with a thorough environmental cleaning program. Continued in-feed supplementation with zinc bacitracin at 100 ppm inhibited proliferation of B. intermedia in experimentally infected birds, whilst at 50 ppm zinc bacitracin encouraged proliferation of Brachyspira pilosicoli. It is uncertain whether these differences are due to the different spirochaete species investigated, or to the dose rates of zinc bacitracin used. Overall, these conflicting results suggest that there are complex interactions between the intestinal microflora and pathogenic intestinal spirochaete species, and that control will require careful monitoring. |
| Project Title | Effects of organic acids, prebiotics, and enzymes on control of necrotic enteritis and performance of broiler chickens |
| RIRDC Project No: | UNE-75A |
| Start Date: | 01/10/00 |
| Finish Date: | 30/09/03 |
| Researcher: | Dr Mingan Choct |
| Organisation: | University
of New England
School of Rural Science and Natural Resources - Animal Science ARMIDALE NSW 2351 |
| Phone: | (02) 6773 5121 |
| Fax: | (02) 6773 3275 |
| Email: | mchoct@metz.une.edu.au |
Objectives |
·
To demonstrate the effect of using organic acids, prebiotics and enzymes
in broilers as alternatives to antibiotic growth promotants to maintain
feed efficiency and general bird health.
· To investigate the effects of these alternative products on the prevention of necrotic enteritis. |
Current Progress |
The
initial stages of this project concentrate on the development of a successful
and repeatable disease model for necrotic enteritis (NE). Models
described in the literature suggest that a dual infection of birds with
Eimeria
and Clostridium perfringens (CP) type A fed a diet high in wheat,
fishmeal and dietary zinc will give the highest occurrence of NE in broilers.
In a series of three experiments, the possibility of artificially introducing NE here at was determined. The first two experiments established that infection of three week old broiler chickens with a dosage of 7000 sporulated oocytes of Eimeria acervuline and E. brunetti will result in a subclinical coccidiosis infection with visible sings of lesions in the upper and lower intestine but only a small reduction in growth performance. A third experiment was designed to introduce NE in three- to four-week-old broiler chickens after a dual infection with coccidiosis (E. acervuline and E. brunetti 7000 oocyst each) and CP (three consecutive infections with 1ml of CP 109 CFU/ml). The result of this experiment showed that birds infected with Eimeria and CP had significantly reduced growth and feed intake and less efficient feed conversion. A future trial will have to be conducted to verify these data and identify NE on the basis of lesion scoring and bacterial enumeration. |
| Project Title | Enhancing mucosal immunity in chickens by novel in-ovo and postnatal vaccination techniques |
| RIRDC Project No: | US-72J |
| Start Date: | 01/01/99 |
| Finish Date: | 31/12/01 |
| Researcher: | Prof Alan Husband |
| Organisation: | The
University of Sydney
Dept of Veterinary Anatomy and Pathology UNIVERSITY OF SYDNEY NSW 2006 |
| Phone: | (02) 9351 3127 |
| Fax: | (02) 9351 7349 |
| Email: | a.husband@vetp.usyd.edu.au |
Objective |
·
To induce long-term immunoenhancement in chickens following early priming
of the avian immune system via in-ovo immunisation through:
- development of naked DNA or recombinant constructs of antigen and/or cytokines; - evaluation of delivery vehicles such as liposomes or biodegradable microspheres; - assessment of immunoregulators for non-specific upregulation of the immune system; and - evaluation of immunisation protocols for enhancing immune responses to routine vaccinations and providing protection from disease challenges such as Salmonella Typhimurium. |
Current Progress |
Initial
contact with and colonisation of the intestinal mucosa by pathogens is
impeded by IgA antibody located at the intestinal surface. Appropriate
vaccination procedures will stimulate intestinal IgA production, protecting
the host from these pathogens. Such IgA antibody production can be
increased through the use of immunoenhancers. Studies undertaken
have investigated the immunoenhancing potential of vitamin E (VE) or the
cytokine interleukin-6 (IL-6), (a communicator of the immune system, whose
mammalian counterpart increases IgA production) to increase IgA antibody
levels following vaccination in chickens.
Dietary VE supplementation, from day old, increased antigen-specific intestinal IgA antibody titres following immunisation with either tetanus toxoid or whole killed Salmonella Typhimurium. At some dose rates, in-ovo delivery of VE with killed S. Typhimurium antigen elicited an increase (not statistically significant) in anti-S. Typhimurium IgA antibody levels post-hatch. Repeated oral delivery of IL-6 to chickens immunised with either tetanus toxoid or whole killed S. Typhimurium increased anti-antigen IgA at the intestinal surface. A live S. Typhimurium challenge model is being established to examine the ability of IL-6 induced increases in IgA antibody following immunisation, to protect chickens from a challenge of S. Typhimurium. |
Bird Nutrition and Feed
Supply
| Project Title | Characterisation of canola meal and cottonseed meal at practical inclusion levels for use in broiler and layer diets |
| RIRDC Project No: | DAQ-264J |
| Start Date: | 01/07/99 |
| Finish Date: | 31/12/01 |
| Researcher: | Dr Rider A Perez-Maldonado |
| Organisation: | Department
of Primary Industries (Qld)
Queensland Poultry Research and Development Centre PO Box 327 CLEVELAND QLD 4163 |
| Phone: | (07) 3824 3081 |
| Fax: | (07) 3824 4316 |
| Email: | Perezr@dpi.qld.gov.au |
Objectives |
·
To measure the variability of glucosinolates, sinapines, condensed tannins
(CT), total phenolics (TP), sulphur and phytic acid levels in canola meal
(CM) and CT, TP and free and bound gossypol levels in cottonseed meal (CSM).
Pesticide residue levels in CSM; AME, amino acid and proximate composition
of CM and CSM will be determined in samples from major processing sites,
three times a year.
· To evaluate the ratio of iron to free gossypol in CSM to optimise production in both broilers and layers. · To determine the upper limits of inclusion of both CM and CSM separately and in combination in broiler and layer diets. ·
To make recommendations to the poultry industries on the nutritional value
of both CM and CSM when included in least-cost poultry diets at levels
close to their upper limit.
|
Current Progress |
During
2000/01 several experiments were conducted to investigate the effects of
CSM or CM fed at levels of 10, 20, 30 or 40% of the diet to broilers and
laying hens. At 21 d chicks fed CSM showed a reduced feed intake (FI) from
the 20% level. Liveweight gain (LWG) was also reduced at 20 and 30% CSM
in the diet but not at the 10 and 40% levels. The feed conversion ratio
(FCR) was only affected at the 20% level, where it was poorer. After 37
d LWG and FCR were not affected by any level of CSM, indicating that older
birds were capable of overcoming any negative effect of CSM observed in
younger birds.
The results for CM indicated that after 21 d chicks fed Pinjarra CM had improved FCR at all levels, with a reduced FI but a good LWG at all but the 40% level. After 37 d a similar pattern of bird performance was observed. After 21d chicks fed Numurkah CM had a reduced FI from the 20% level but there was no effect on FCR and LWG even at the 30% level. After 37 days birds showed a similar FI and LWG response but with significantly improved FCR at all levels. After 21 d Newcastle CM resulted in a poorer FCR from the 30% level but a good LWG and FI was observed at all levels except the 40% level. However, after 37d the birds overall FI and LWG was reduced from the 20 and 30% level, respectively, without affecting the overall FCR. After 21 d Melbourne CM resulted in a reduction in LWG and FI from the 20 and 30 % levels, respectively. However, after 37d an improved FCR was observed at all levels, even though FI and LWG were reduced from 20% level. Oil processing conditions and the presence of anti-nutritional factors may have influenced the overall performance in these meals. Although these results demonstrate that substantial amounts of CSM and CM can be used in broiler diets, more detailed studies are being undertaken to confirm the above findings. In the layer experiments, good performance was obtained when feeding CSM or different sources of CM at levels of 10, 15, or 20% of the diet. However, preliminary observations made to evaluate fresh and stored eggs derived from the above experiments indicated that an abnormal odour (fishy taint) was detected in raw eggs derived from brown layers on all CM diets. Due to the importance of this observation, further work is being undertaken using an expert sensory panel to evaluate eggs derived from hens fed CM and CSM diets. |
| Project Title | Estimating lysine availability by slope-ratio chick assay |
| RIRDC Project No: | DAQ-277A |
| Start Date: | 01/10/00 |
| Finish Date: | 30/09/01 |
| Researcher: | Dr Rider Perez-Maldonado |
| Organisation: | Department
of Primary Industries (Qld)
PO Box 327 CLEVELAND QLD 4163 |
| Phone: | (07) 3824 3081 |
| Fax: | (07) 3824 4316 |
| Email: | perezr@dpi.qld.gov.au |
Objectives |
·
To establish and validate a slop-ratio chick assay to determine the availability
of lysine in selected samples of canola meal and cottonseed meal.
· To compare
lysine availability values with ileal apparent digestibility values determined
in the same samples of canola meal and cottonseed meal.
|
Current Progress |
Samples
of canola meal (CM) from Newcastle, Melbourne, Numurkah, and Pinjarra and
cottonseed meal (CSM) from Narrabri were obtained during 1999-2000 from
Australian oilseed processors. Every CM and CSM samples was chemically
analysed with an AME determination in broiler and layers, and a digestible
amino acid determination made using broilers birds.
During April-May 2001 a broiler experiment using canola meal was conducted to obtain information on the effect of formulating diets on a digestible and a total amino acid basis. The experiment was carried out in two phases, from 0-21 days (starter diets) and from 22-42 days of age (finisher diets). Dietary treatments included CM from each source which were fed at three dietary levels (20, 30 and 40%). The results of this experiment are under evaluation. A similar experiment will be conducted using cottonseed meal. It is expected that the chick assay to determine the availability of lysine in CM and CSM samples will be carried out later next year. |
| Project Title | Inclusion of data for additional livestock species in the Australasian Livestock Feed Ingredient (ALFI) database |
| RIRDC Project No: | GRD-2J |
| Start Date: | 01/04/99 |
| Finish Date: | 30/06/01 |
| Researcher: | Dr Robert van Barneveld |
| Organisation: | Grains
Research and Development Corporation
C/- Barneveld Nutrition Pty Ltd PO Box 42 LYNDOCH SA 5351 |
| Phone: | (08) 8524 6477 |
| Fax: | (08) 8524 6577 |
| Email: | robvanb@dove.net.au |
Objective |
· To improve knowledge of the nutritional value of feed grains and the efficiency of use of these grains by the egg and chicken meat industries through development of a commercial version of the Australasian Livestock Feed Ingredient (ALFI) database containing data for pigs, poultry (layers and broilers) and aquaculture species. |
urrent Progress |
The
Australasian Livestock Feed Ingredient (ALFI) database now contains more
than 22,332 sample entries on the chemical composition of feed ingredients
and the nutritional value of these ingredients for pigs, poultry (layers
and broilers) and aquaculture species. ALFI also incorporates a vast
range of information contained in recent literature and other relevant
databases.
The re-programmed version of ALFI has been tested by the major stakeholders and the programming of the database is now complete. A business plan has been prepared for commercialisation of the ALFI database based on distribution to end-users as a subscription service via the internet or as a CD-ROM. Final negotiations with stakeholders on commercialisation are under way. |
| Project Title | Premium Grains for Livestock Program (stage 2) |
| RIRDC Project No: | GRD-3J |
| Start Date: | 01/07/00 |
| Finish Date: | 30/06/03 |
| Researcher: | Dr John Black |
| Organisation: | John
L Black Consulting
Locked Bag 21 WARRIMOO NSW 2774 |
| Phone: | (02) 4753 6231 |
| Fax: | (02) 4753 6295 |
| Email: | jblack@pnc.com.au |
Objective |
·
This project is the second stage of a major research program for improving
feed grains quality and marketing that has been negotiated in response
to identified industry needs. It has five integrated component projects:
1) coordination 2) production, storage and distribution of grain samples 3) rapid and objective analytical tests for assessing feed grains quality 4) enhancing grain nutritional value through breeding and processing and 5) modelling feed grain quality.
|
Current Progress |
Several hypotheses about the factors determining the nutritional value of cereal grains for ruminants, pigs and poultry were established in the predecessor Project GRD-1J. The relative proportion of the main chemical components of a grain is the major determinant of nutritional value for all classes of livestock. However, other grain characteristics can significantly affect energy availability and these differ between ruminants, pigs and poultry. Prediction of AME in poultry based on an assumed constant digestion of individual gross chemical components of grains show close agreement with observed values for sorghum and oats, but not for wheat or barley. The accuracy of predictions for triticale was intermediate between sorghum and barley. Further analyses showed that some of the difference between predicted and observed AME values could be explained by the viscosity of ileal digesta. However, other factors such as grain hardness and hydration capacity appear to be associated with the variation in AME between grains. In addition, starch characteristics such as granule size and distribution, amylose:amylopectin ratio and gelatinisation temperature may influence the extent of starch digestion in the small intestines of poultry and therefore energy availability. These hypotheses will be tested further in poultry over the coming year. |
| Project Title | Physiological limitations in energy metabolism reduce production efficiency of broilers |
| RIRDC Project No: | SAR-13A |
| Start Date: | 31/10/98 |
| Finish Date: | 31/03/02 |
| Researcher: | Mr Bob Hughes |
| Organisation: | South
Australian Research and Development Institute
Nutrition Laboratory PPPI, Roseworthy Campus ROSEWORTHY SA 5371 |
| Phone: | (08) 8303 7788 |
| Fax: | (08) 8303 7975 |
| Email: | hughes.bob@pi.sa.gov.au |
Objectives |
·
To develop non-invasive methods for measuring gut function in chickens.
· To define the role of gut structure and function in limiting energy metabolism. · To identify the mechanism(s) by which physical and chemical properties of feed promote sub-optimal digestion of energy. · To develop
a clearer understanding of the physiological limitations of digestion which
will under-pin opportunities for development of specific strategies to
reduce the cost of production of lean chicken meat.
|
Current Progress |
Key
findings to date are that gut morphology and bacterial colonisation of
the gut are at least partially dependent on the sex of the chicken.
Clearly, gut microflora have a highly significant impact on between-bird
variation in energy metabolism in broilers. This has very important
commercial implications in the nutrition and management of broilers.
Sex-related differences may be important in utilisation of energy and other
nutrients, in responses to anti-nutritional factors (such as non-starch
polysaccharides) and various feed additives including enzymes, and in efficacy
of vaccines and medication to treat gut pathogens.
Up to one third of the variation in apparent metabolisable energy (AME) was associated with physical features of the small intestinal mucosa. Ileal crypt depth was the single most important feature of the small intestinal mucosa associated with variation in AME. Villus heights of the mucosa in the jejunum and ileum were significantly affected by the breed and sex of chicken, respectively. Remodeling of the villus/crypt axis, presumably in response to dietary non-starch polysaccharides in the wheat, differed in male chickens depending on breed, but there were no differences observed in female chickens. Changes in hydrogen and methane concentrations in breath during two metabolism studies were highly variable. However, observed variation between individual birds in AME was not directly associated with breath hydrogen concentration. However, elevated levels of hydrogen in breath were associated with significant reductions in growth rate and feed efficiency due to losses of energy and other nutrients through proliferation of gut bacteria. |
| Project Title | Improving the utilisation of dietary amino acids in meat chickens |
| RIRDC Project No: | US-80A |
| Start Date: | 01/04/99 |
| Finish Date: | 31/03/02 |
| Researcher: | A/Prof Wayne Bryden |
| Organisation: | The
University of Sydney
Dept of Animal Science Werombi Road CAMDEN NSW 2570 |
| Phone: | (02) 4655 0658 |
| Fax: | (02) 4655 0693 |
| Email: | wayneb@camden.usyd.edu.au |
Objective |
· To improve the efficiency of utilisation of amino acids in meat chickens by formulating diets on a digestible amino acid basis; determining ideal digestible amino acid requirements; and identifying factors that influence endogenous amino acid losses. |
Current Progress |
Studies
have been completed in which broiler diets were formulated for the growing
cycle (starter, grower and finisher) using both total and digestible amino
acid values. The results demonstrate clearly that using digestible
amino acid values can significantly improve bird performance (growth rate,
feed intake, feed conversion), breast meat yield and reduce abdominal fat
pad mass.
Determination of the ileal amino acid digestibility of feed ingredients used in the poultry industry is ongoing and has been extended to evaluate the effect of feed enzymes (xylanase, phytase), individually or in combination. The results suggest that the strategic dietary inclusion of exogenous enzymes will improve apparent amino acid digestibility. |
| Project Title | Use of dietary fatty acids to increase protein accretion in broilers |
| RIRDC Project No: | US-104A |
| Start Date: | 01/02/01 |
| Finish Date: | 30/04/04 |
| Researcher: | A/Prof Wayne Bryden |
| Organisation: | The
University of Sydney
Dept of Animal Science Werombi Road CAMDEN NSW 2570 |
| Phone: | (02) 4655 0658 |
| Fax: | (02) 4655 0693 |
| Email: | wayneb@camden.usyd.edu.au |
Objective |
· To develop a simple feed technology to reduce fat deposition and increase muscle protein accretion in broilers by manipulating dietary fatty acid intake to alter tissue sensitivity to the metabolic hormones involved in lipid and protein metabolism. |
Current Progress |
Studies
have commenced with fish oil (n-3 fatty acids), and sunflower oil (n-6
fatty acids) in comparison with tallow (saturated fatty acids) to determine
the dietary concentration and duration of feeding required of the two polyunsaturated
fat sources to change carcass composition and reduce fat deposition in
broiler chickens.
The studies will be extended to evaluate the effects of conjugated linoleic acid on carcass composition and performance of broilers. |
| Project Title | Salmonella typing and colonisation of chickens by characterised S. Sofia |
| RIRDC Project No: | IMV-3A |
| Start Date: |