OINT CHICKEN MEAT & EGGSs- Completed Projects

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RIRDC Completed Projects in 1998-1999 & Research in Progress as at June 1999
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SUB-PROGRAM 3.1 & 3.2 - JOINT CHICKEN MEAT & EGGS

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COMPLETED PROJECTS
PROJECT No	PROJECT TITLE	RESEARCHER	PHONE	ORGANISATION
DAQ-228A	Raw soybeans selected for low trypsin inhibitor activity in poultry diets	Dr R. Perez-Maldonado, Mr P.F. Mannion, Dr D.J. Farrell, Mr A.T. James	07 3824 3081	Department of Primary Industries (Qld)
UMU-21A	Intestinal spirochaete infections in chickens in eastern Australia	Associate Professor David Hampson	08 9360 2287	Murdoch University
UNS-9A	Evaluation of the VICAM SE screen/verify system for detection of salmonella enteritidis in poultry flocks	Dr Julian Cox and Ms Belinda Chung	02 9385 5665	University of New South Wales

RESEARCH IN PROGRESS
PROJECT No	PROJECT TITLE	RESEARCHER	PHONE	ORGANISATION
CSA-1A	Detection of exotic strains of Newcastle disease virus in chickens previously infected with Australian strains of the virus	Dr Harvey Westbury	03 5227 5115	CSIRO Animal Health AAHL
CSA-2A	Diagnostic tools for detection of vvIBDV strains and characterisation of Australian variants	Dr Jagoda Ignjatovic	03 5227 5769	CSIRO Animal Health
CSA-7A	Therapeutic applications of chicken interferon-gamma (ChIF-g ) in poultry	Dr John Lowenthal	03 5227 5759	CSIRO Animal Health
DAQ-243A	Nutritional value of pearl millet as poultry feed	Mr Danny Singh	07 3362 9479	Department of Primary Industries (Qld)
DAQ-244A	Investigations into the management of the darkling beetle, Alphitobius diaperinus (Panzer)	Mr Trevor Lambkin	07 3896 9434	Department of Primary Industries (Qld)
GRD-1A	Improving feed grains quality	Dr John Black	02 4753 6231; 0419 493 567	John L Black Consulting
RMI-6A	The development of effective immunisation strategies against Marek's disease	Prof Greg Tannock	03 9925 2779	Royal Melbourne Institute of Technology
RMI-8A	Characterisation of very virulent Australian isolates of Marek's disease virus	Prof Greg Tannock	03 9925 2779	Royal Melbourne Institute of Technology
UM-33A	Development of improved serological diagnosis of Mycoplasma synoviae	Dr Glenn Browning	03 9344 7342	University of Melbourne
US-51A	Total and digestible tryptophan content of feedstuffs for poultry	A/Prof Wayne Bryden	02 4655 0658	University of Sydney
US-72A	Enhancing mucosal immunity in chickens by novel in-ovo and postnatal vaccination techniques	Prof Alan Husband	02 9351 3127	University of Sydney

Completed Projects

Project Title	Raw soybeans selected for low trypsin inhibitor activity in poultry diets
RIRDC Project No.:	DAQ-228A
Researcher:	R. Perez-Maldonado, P.F. Mannion, D.J. Farrell, A.T. James
Organisation:	Department of Primary Industries (Qld) The Queensland Poultry Research and Development Centre PO Box 327 CLEVELAND QLD 4163
Phone:	07 3824 3081
Fax:	07 3824 4316
Email:	rider@mailbox.uq.oz.au
Objectives	To evaluate by means of feeding trials new low trypsin inhibitor soybean genotypes (developed by CSIRO) as a low-cost source of high quality protein and energy to the chicken meat and egg industries; To provide recommendations to industry on the nutritional value of selected genotypes and hence their commercial attributes in least-cost poultry diets.
Background:	Full fat soybeans are a concentrated energy source and have a high protein content that has a well-balanced amino acid profile. Unfortunately, soybean seeds contain a number of natural toxins for poultry, the most problematic being two proteinase inhibitors. These inhibitors result in decreased pancreatic trypsin and chymotrypsin activities during digestion, causing pancreatic enlargement and poor growth rate in chicks or reduced egg production and egg size in layers. Trypsin inhibitors can be denatured by heat, as with the manufacture of soybean meal. Heat treatment adds to the cost of soybean meal for poultry diets and the heat treatment process must be carefully controlled to avoid reducing the protein quality and amino acid availability of the meal. CSIRO have recently developed new genotypes of soybeans (Kti) that are lacking one of these trypsin inhibitors (Kunitz). Two broiler experiments and one layer experiment were conducted to evaluate these new genotype soybeans in poultry diets. Since one of the trypsin inhibitors (Bowman-Birk) is known to account for almost half of the cystine content of soybean meal, and it is suspected that this cystine may be unavailable to the bird for growth, the supplementation of broiler diets containing soybeans with DL-methionine was investigated.
Research	Two broiler trials and one layer trial were conducted to compare the performance of Kti soybeans in poultry diets with or without pelleting and methionine supplementation.
Outcomes	Compared with a control diet containing full fat soybean meal the raw Kti soybeans resulted in reduced liveweight gain, feed intake and feed conversion efficiency and increased pancreas weights in broilers, although performance was better than broilers fed raw conventional soybeans. Steam pelleting raw conventional or Kti soybeans failed to overcome this effect, indicating that the temperatures reached with steam pelleting are insufficient to destroy the trypsin inhibitor activity. Supplementing with DL-methionine did not improve performance and may indicate that the depression of liveweight gain from feeding raw soybeans was too severe to be compensated for by the level of supplementation tested. Levels of Kti up to 110 g/kg were found to support normal feed intake and egg production in laying hens.
Implications	The inclusion of 110 g/kg raw Kti soybeans in layer diets supported normal egg production. An estimate of the economic consequences of using raw Kti soybeans to replace full fat soybean meal demonstrated a profit of $39,375.10 per 100,000 laying hens over a period of 20 weeks. The residual trypsin inhibitor activity of Kti soybeans makes them unsuitable for use in broiler diets without heat inactivation.
Publications:	Perez-Maldonado, R.A., Mannion, P.F., Farrell, D.J. and James, A.T. (1998). Measurements Made On Broilers Given Diets With Processed And Raw Soybean Of High And Low Trypsin Inhibitor Activity. Proceedings 10^thAustralian Soybean Conference 10, 180. Perez-Maldonado, R.A., Mannion, P.F., Farrell, D.J. and James, A.T. (1999). Raw Soybean Selected for Low Trypsin Inhibitor Activity For Poultry Diets. Proceedings of Queensland Poultry Science Symposium. 1999 (in press).

Project Title	Intestinal spirochaete infections in chickens in eastern Australia
RIRDC Project No.:	UMU-21A
Researcher:	A/Prof Professor 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 determine the prevalence and disease associations of infection with intestinal spirochaetes in major broiler, broiler breeder and layer flocks in the eastern states of Australia, To compare these findings with those already made in Western Australia.
Background:	Intestinal spirochaetal bacteria of the genus Serpulina have recently been identified as a previously-unrecognised cause of diarrhoea, wet litter and/or reduced egg production in broiler breeder and layer flocks in Europe and the USA. A survey in Western Australia confirmed that these organisms occurred commonly in flocks of this type, and moreover were significantly associated with the same sorts of production problems. Several species of the organisms were identified, with the known pathogenic species Serpulina intermedia apparently being the major cause for concern. The situation in the rest of Australia was uncertain and this prompted the current survey to be conducted.
Research	Faecal samples were collected from 52 broiler, broiler breeder and layer flocks in Queensland, New South Wales, Tasmania, Victoria and South Australia. These were cultured for intestinal spirochaetes on selective media and faecal dry matter content was determined. The presence of spirochaetes was correlated with reported clinical problems on the farms and with the measured faecal water content. Spirochaetes were identified to the species level using a panel of polymerase chain reaction tests.
Outcomes	Substantial levels of colonisation with intestinal spirochaetes (55.3% overall) were found in broiler breeder and layer flocks in the eastern states of Australia. Consistent with previous findings in Western Australia and Europe, no broiler (meat) flocks were infected. Within infected adult flocks multiple sheds were frequently involved, and around half of the samples from these sheds were positive. Half the isolates tested belonged to two species of intestinal spirochaetes that are known to be pathogens of poultry (S. intermedia and S. pilosicoli); both are also pathogens of pigs. The latter species was not previously detected in chickens tested in Western Australia and its frequent presence in flocks in eastern Australia adds to the complexity of controlling these infections. There was a strong significant association between colonisation with spirochaetes and the occurrence of wet litter problems and/or reduced egg production. The faeces of colonised flocks were on average 14% wetter than those of non-colonised flocks.
Implications	The chicken meat (breeder) and layer industries need to be aware that intestinal spirochaete infections are extremely common in flocks throughout Australia and that they may be causing significant economic problems associated with wet litter (diarrhoea) and reduced egg production. As appropriate diagnostic tests are not currently being conducted these infections are going unrecognised and the cause of such performance problems may be incorrectly diagnosed. Further research directed towards developing improved methods for diagnosis and control of these infections is warranted.

Project Title	*Evaluation of the VICAM SE screen/verify system for detection of Salmonella* Enteritidis in poultry flocks**
RIRDC Project No.:	UNS-9A
Researcher:	Dr Julian Cox and Ms Belinda Chung
Organisation:	University of New South Wales Department of Food Science and Technology Sydney NSW 2052
Phone:	02 9385 5665
Fax:	02 9385 5931
Email:	julian.cox@unsw.edu.au
Objective	To determine the efficacy of the Vicam SE Screen/Verify system for monitoring Salmonella Enteritidis in the poultry industry.
Background:	The problem of human gastrointestinal disease due to Salmonella Enteritidis (SE) is well known to the poultry industry and is a problem, primarily in the egg industry but also the broiler industry, in many parts of the world. While Australia is currently free of this problem, the local poultry industry must remain vigilant in order to maintain this status. To that end, a technology for screening product and environmental samples specifically for SE is required and a US product, the Vicam Screen/Verify system, may be suitable for this purpose. The Vicam system comprises two technologies. The Screen component relies on a method known as immunomagnetic separation (IMS) in which Salmonella is selectively removed from a suspension or culture of a sample by small beads coated with antibodies. The Verify component involves latex agglutination, in which the presence of SE in a sample is demonstrated by the clumping of small latex particles due to the interaction of antibodies on the beads with specific antigens on the bacteria.
Research	A series of experiments with pure cultures of SE and other related bacteria (either alone or in mixtures) as well as analysis of egg products, cloacal swabs or faecal specimens (alone or artificially inoculated with SE), were used to evaluate the Screen and Verify components of the Vicam SE test.
Outcomes	The IMS-based Screen component of the test was generally inadequate for the purpose of selecting SE from cultures of samples, with the exception of egg products. This was due to selection of Salmonella other than SE, or non-specific attachment of other bacteria to the IMS beads. The LA-based Verify component could be used to screen enrichment cultures of environmental samples directly, without IMS, and is likely to prove useful in the same way for egg products. A limitation of the LA technology was its lack of reaction with a number of SE strains.
Implications	This study highlights the need to continue to pursue methods for the specific detection of Salmonella Enteritidis. The SE Verify latex agglutination reagent can be used to detect the presence of SE in enrichment cultures of environmental samples. However, the lack of reactivity with a significant proportion of the isolates of SE tested in this study suggests that the reagent may be incapable of detecting SE, should an industry problem arise.

Research in Progress

Project Title	Detection of exotic strains of Newcastle disease virus in chickens previously infected with Australian strains of the virus
RIRDC Project No.:	CSA-1A
Start Date:	1/07/97
Finish Date:	30/06/01
Researcher:	Dr Harvey Westbury
Organisation:	CSIRO Animal Health Australian Animal Health Laboratory PO Box 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 exotic strains of Newcastle disease virus (NDV) in flocks previously infected with endemic lentogenic strains of the virus.
Current Progress:	A virus capture ELISA for Newcastle disease virus (NDV) has shown considerable promise as a virus detection technique. It is able to specifically and sensitively detect NDV in certain tissues of chickens infected with virulent viscerotropic, neurotropic or pneumotropic strains of the virus. Bone marrow and spleen of chickens infected with these strains have been found to be excellent target organs for virus detection using this technique. It is not a pathotyping technique, although it is hoped that it will be possible to show that the virus this test detects in spleen and/or bone marrow is always/usually virulent, particularly in chickens previously exposed to avirulent strains of the virus. Pathotyping techniques based on nucleotide sequencing of a fragment of the Fusion (F) gene of the virus will be used for this purpose. Work on the detection of virulent virus in organs of chickens previously infected with avirulent strains of the virus is now progressing. The first trial using chickens immunised with NDV strain V4 and then challenged with the virulent Herts strain of the virus is complete. Chickens immunised with V4 were partitioned into different groups defined by their haemagglutination inhibition antibody status as a guide to their level of immunity. This was done to assess whether the level of immunity impacted on the test’s capacity to detect virus at various times up to 14 days after challenge have been collected and are currently being processed for virus detection by ELISA. Trials using the PCR technique have demonstrated that this technique can be used to detect NDV in tissues of infected chickens and in paraffin embedded blocks of tissues from such chickens. More work is required on this technique to make it a robust test suitable for routine use and technology transfer.

Project Title	Diagnostic tools for detection of vvIBDV strains and characterisation of Australian variants
RIRDC Project No.:	CSA-2A
Start Date:	1/07/97
Finish Date:	30/06/00
Researcher:	Dr Jagoda Ignjatovic
Organisation:	CSIRO Animal Health Private Bag No 24 GEELONG VIC 3220
Phone:	03 5227 5769
Fax:	03 5227 5555
Email:	Jagoda.Ignjatovic@dah.csiro.au
Objectives	To develop diagnostic tools to detect exposure of local poultry to very virulent (vv)IBDV strains, where the birds are already immune to endemic strains. To determine the nucleotide sequence of vv IBDV strains from neighbouring countries to assess the genetic diversity of these viruses and assure the detection of all strains. To further characterise of Australian variant IBDV strains which differ from the overseas variants, in order to obtain a better understanding of the significance of changes detected in local strains.
Current Progress:	Following the importation of virulent CS88, virulent 52/70 and low virulence 1/68 strains of infectious bursal disease virus (IBDV), these strains have been tested for their pathogenicity in specific pathogen free (SPF) chickens. Infection was performed within the high containment area of the Australian Animal Health Laboratory. As expected, both CS88 and 52/70 induced mortalities in three week old SPF chicks, whereas 1/68 induced prominent clinical signs typical of IBD but without any mortality. Thus, the low virulence European strain 1/68 in our tests was more pathogenic for chicks than any of the classical Australian IBDV strains which did not induce any clinical disease in SPF chicks of the same age. A trial was completed in which the efficacy of inactivated IBDV vaccines derived from classical and variant strains were compared. Preliminary analysis of results confirmed that inactivated vaccines based on classical strains did not protect chicks against challenge with variants. In an effort to identify antibodies which are specific for very virulent IBDV strains and hence which may be used in a test to detect such strains and distinguish them from classical or low virulence strains in chickens, recombinant antibody libraries were generated from chicks immunised with very virulent IBDV strains VB849 and CS88. Positive clones were selected from the CS88 derived library by panning, however specificity testing showed that these clones were not specific for very virulent IBDV strains. An alternative selection strategy is now being developed in order to increase the antibody diversity obtained from the panning process.

Project Title	Therapeutic applications of chicken interferon-gamma (ChIF-g ) in poultry
RIRDC Project No.:	CSA-7A
Start Date:	1/07/98
Finish Date:	30/06/01
Researcher:	Dr John Lowenthal
Organisation:	CSIRO Animal Health Private Bag 24 GEELONG VIC 3213
Phone:	03 5227 5759
Fax:	03 5227 5531
Email:	john.lowenthal@dah.csiro.au
Objective	To enhance disease resistance and vaccine efficacy in poultry by administering theraputic doses of chicken interferon-gamma to commercial broilers and layers.
Current Progress:	The use of antibiotics in food production animals has been suggested to be associated with the emergence of drug resistant bacteria and the possibility that limitations may be placed on their use in the future has intensified the search for alternative methods to control disease. Cytokines, as natural mediators and regulators of the immune response, offer exciting new alternatives to conventional therapeutics. In collaboration with the poultry industry, field trials will be undertaken in order to test the ability of interferon-gamma (ChIFN-g) to enhance vaccine efficacy and disease resistance in poultry. Currently research is focussing on identifying the best way of producing commercial-scale recombinant ChIFN-g. ChIFN-g has been expressed in E. coli, plants and baculovirus and a yeast expression system is under development. Cytokines are typically short-lived in vivo, so extending their life span should increase their activity. A critical step in assessing this is measuring how long recombinant ChIFN-g remains intact after in vivo administration. Since there was no existing method of detecting ChIFN-g in vivo, a panel of monoclonal antibodies to ChIFN-g was produced and used to develop a sensitive ELISA capable of measuring serum levels of cytokine. Together with industry, pen trials are being planned to assess the effectiveness of different preparations of ChIFN-g.

Project Title	Nutritional value of pearl millet as poultry feed
RIRDC Project No.:	DAQ-243A
Start Date:	1/07/98
Finish Date:	30/04/99
Researcher:	Mr Danny Singh
Organisation:	Department of Primary Industries (Qld) Animal Research Institute Locked Mail Bag No 4 MOOROOKA QLD 4105
Phone:	07 3362 9479
Fax:	07 3362 9429
Email:	singhd@dpi.qld.gov.au
Objectives	To evaluate the nutritional value of Australian pearl millet varieties as a high quality feed for poultry. To provide information to the poultry industries on the nutritional value of pearl millet in least-cost diet formulation. To promote the benefits of pearl millet varieties as a feed grain to both grain growers and poultry producers.
Current Progress:	The two millet varieties investigated were Katherine and Siberian. The protein, fibre, total starch, metabolisable energy and amino acid profiles were found to be different between the two millets. Katherine millet had higher protein (13.7%), starch (63.4%) and energy content (14.1 MJ/kg DM) and lower fibre content (5.1%) compared to Siberian millet (11.8%, 53%, 13.7 MJ/kg DM and15.4 %). The lysine, tryptophan and threonine levels in Katherine were 3.41, 3.15 and 4.44 g/kg DM as compared to 1.50, 1.58 and 3.33 g/kg DM in Siberian millet. The performance of layer birds has been evaluated by feeding three levels of Katherine millet (20,40 and 60%) and one level of Siberian (40%). These were compared to a commercial layer diet. Each of the five diets was fed to 30 Isabrown birds for 20 weeks. The diets were formulated to contain similar energy and protein levels and to satisfy the minimum nutrient requirements for maximum egg production. The results from the layer experiment show that there were no significant differences in terms of egg production, egg weight, egg mass and FCR. The only difference was in terms of food intake with Siberian millet fed birds eating more. This could be due to the higher fibre content in this diet. It appears that pearl millet could be used in layer diets to a fairly high level, substituting for the more expensive soybean meal and for some sorghum and wheat. Experiments are currently under progress to determine the AME values of these pearl millet varieties for broilers and the digestible amino acid content of the millet varieties when fed to layer and broiler chickens.

Project Title	*Investigations into the management of the darkling beetle, Alphitobius diaperinus* (Panzer)**
RIRDC Project No.:	DAQ-244A
Start Date:	1/07/98
Finish Date:	30/06/00
Researcher:	Mr Trevor Lambkin
Organisation:	Department of Primary Industries (Qld) Farming Systems Institute (Entomology) 80 Meiers Road INDOOROOPILLY QLD 4068
Phone:	07 3896 9434
Fax:	07 3896 9446
Email:	lambkint@dpi.qld.gov.au
Objectives	To undertake a survey of insecticide resistance of the darkling beetle in broiler houses and in deep litter egg production units in south east Queensland. To develop an improved understanding of the ecology of the darkling beetle.
Current Progress:	The aims of the current studies of the darkling beetle are to develop a better understanding of the pest in Australian poultry systems and, eventually, to develop practices to successfully reduce pest numbers. Successful reduction of beetle numbers throughout the industry will minimise the risk of disease transfer and reduce current levels of fenitrothion use. In the first year of the project a complete bibliographic review of all published papers on darkling beetle research has been undertaken. A successful beetle laboratory culture method has been developed to provide a ready supply of beetles for laboratory studies. These beetles have been used for the successful development of a laboratory insecticide testing method for the pest. Test results have indicated that a high level of fenitrothion resistance occurs in most beetle populations associated with the poultry industries, but the highest resistances occur in populations of darkling beetles that have been exposed to continuous use of fenitrothion for 15-20 years. The most resistant population tested so far has come from a broiler farm and is 33 times more resistant than a susceptible reference population that has never been exposed to fenitrothion. Surveying and testing of deep litter egg barn beetle populations will soon commence and further surveying of broilers will continue. Testing of other registered insecticides against fenitrothion resistant and susceptible beetle populations will commence shortly.

Project Title	Improving feed grains quality
RIRDC Project No.:	GRD-1A
Start Date:	15/04/97
Finish Date:	30/06/00
Researcher:	Dr John Black
Organisation:	John L Black Consulting Locked Bag 21 WARRIMOO NSW 2774
Phone:	02 4753 6231; 0419 493 567
Fax:	02 4753 6295
Email:	jblack@pnc.com.au
Objectives	A major research program for improving feed grains quality and marketing has been negotiated in response to identified industry needs. It has five integrated component projects 1. Co-ordination 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:	Approximately 1700 cereal grains have been obtained over three seasons from plant breeders, farmers in different environments or collected opportunistically because of adverse effects of weather on grain quality. Twelve sorghum and 11 barley samples have been fed to different animal species including broiler chickens and laying hens. In broiler chickens, apparent metabolisable energy (AME) values varied little for sorghum grain (15.44 to 15.75 MJ/kg DM), but varied markedly for barley (11.55 to 13.30 MJ/kg DM). Across all grains examined AME in broilers correlated strongly with voluntary feed intake (r = 0.88) and viscosity of ileal digesta (r = 0.71). The AME results for laying hens showed a similar small range for sorghum and a larger range for barley. The same barley samples had the highest and lowest AME values in both broilers and hens, with a strong correlation (r = 0.97) between AME observations in the two classes of poultry. These similarities support the concept that AME values measured in broilers can be used to predict AME for laying hens. AME values obtained with adult cockerels were also similar to those for laying hens. Analyses are continuing to identify the major chemical and physical determinants of AME for grains in poultry.

Project Title	The development of effective immunisation strategies against Marek's disease
RIRDC Project No.:	RMI-6A
Start Date:	1/07/97
Finish Date:	30/06/00
Researcher:	Prof Greg Tannock
Organisation:	Royal Melbourne Institute of Technology Department of Applied Biology & Biotechnology Virology Laboratory GPO Box 2476V MELBOURNE VIC 3001
Phone:	03 9925 2779
Fax:	03 9662 3421
Email:	gtan@rmit.edu.au
Objectives	To develop effective immunisation strategies for the prevention of Marek's disease using newer vaccines or modifications to existing vaccines. Newer vaccines will comprise serotype 1 viruses that are currently under development. Other vaccines will comprise imported serotype 1 vaccines, either alone or in combination with existing serotype 2 and 3 vaccines. To improve the performance of existing vaccines using suitable adjuvants. To characterise MDV strains after adaptation to continuous cell lines.
Current Progress:	Recent pen trials using Cobb breeder birds and the RMIT serotype 1 vaccine have confirmed previously results obtained with SPF birds that the RMIT vaccine is safe but marginally less immunogenic than the existing Rispens vaccine. The RMIT vaccine will now be stored for later possible use should changes in field virus isolates take place. It is proposed to undertake an evaluation of two adjuvants in an attempt to enhance the performance of HVT vaccine in chickens. The adjuvants are (i) gamma inulin, a polysaccharide shown to boost the performance of vaccines to influenza and hepatitis in mice and (ii) STM-1, a live attenuated Salmonella vaccine that has previously been shown to enhance HVT responses in chickens. Studies on the immunogenicity of HVT grown in vero continuous cell lines are planned for later this year.

Project Title	Characterisation of very virulent Australian isolates of Marek's disease virus
RIRDC Project No.:	RMI-8A
Start Date:	1/10/97
Finish Date:	30/09/00
Researcher:	Prof Greg Tannock
Organisation:	Royal Melbourne Institute of Technology Virology Laboratory Dept of Applied Biology and Biotechnology GPO Box 2476V MELBOURNE VIC 3001
Phone:	03 9925 2779
Fax:	03 9662 3421
Email:	gtan@rmit.edu.au
Objectives	The major aim of the project is to collect and maintain Marek's disease viruses (MDVs) isolated from flocks in different parts of Australia and to characterise them by molecular and biological tests. Additional aims are to determine optimum methods for standardising Australian Marek's disease vaccines; to prepare and maintain reference preparations of viruses for use in vaccine assays; to provide a vaccine assay facility for use by Australian vaccine manufaturers as and when required and in harmony with requirements set by the National Registration Authority (NRA).
Current Progress:	Over 100 isolates have been obtained from Marek’s disease virus (MDV) problem flocks from different regions of Australia in the last twelve months. Isolates have been initially screened for serotype 1 MDV using PCR. Samples from flocks that were not vaccinated with serotype 1 vaccines and tested PCR positive have been retained for passage in primary chicken embryo kidney cultures. It is proposed to expand the MDV isolation program during the coming twelve months. Assay procedures have been established to estimate infectious titres of Marek’s disease vaccines used in Australia. Towards the establishment of a Marek’s disease vaccine assay national reference centre, contact has been made with the National Registration Authority (NRA) with a view to obtaining accreditation by the end of 1999. For accreditation, standard operating procedures (SOPs) for vaccine assays will be submitted within six months.

Project Title	Development of improved serological diagnosis of Mycoplasma synoviae
RIRDC Project No.:	UM-33A
Start Date:	1/07/96
Finish Date:	31/12/99
Researcher:	Dr Glenn Browning
Organisation:	University of Melbourne Veterinary Preclinical Centre PARKVILLE VIC 3052
Phone:	03 9344 7342
Fax:	03 9344 7374
Email:	g.browning@vet.unimelb.edu.au
Objectives	To identify, characterise, clone and express the genes for M. synoviae specific antigens. To develop and assess a highly specific serological test for M. synoviae infections, based on cloned, expressed antigens. To improve diagnosis of M. synoviae infection in the field and also enable the accurate assessment of effective vaccination. To improve the control of mycoplasmosis in chickens. To assess the potential for developing a serologically marked strain of the temperature sensitive MS-H vaccine strain of M. synoviae.
Current Progress:	The genes for M. synoviae specific antigens have been identified, cloned and partially expressed in E. coli in a vector which enables rapid, inexpensive purification. The immunodominant region of one of the proteins has been identified and this region, expressed in E. coli, assessed as an ELISA antigen and as an antigen for latex agglutination assays. Its performance in trials indicates it is a more sensitive antigen than the rapid slide agglutination antigen, especially early in infection. Unfortunately, the two species specific proteins are unlikely to be suitable targets for development of a marked strain of the MS-H vaccine as they are both produced by the same gene and this gene is part of a multigene family, precluding deletional mutagenesis. ELISA assays based on the expressed antigen will overcome problems of variability in slide agglutination antigen and will enable earlier diagnosis, thus improving control of M. synoviae.

Project Title	Total and digestible tryptophan content of feedstuffs for poultry
RIRDC Project No.:	US-51A
Start Date:	1/07/97
Finish Date:	30/06/99
Researcher:	A/Prof Wayne Bryden
Organisation:	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 database of the total and digestible tryptophan contents of feedstuffs for poultry which can be used by the feed industry to formulate more efficient diets.
Current Progress:	While most amino acids are routinely analysed by ion-exchange chromatography following acid hydrolysis, tryptophan is destroyed by these conditions. For this reason, analysis of tryptophan has to be carried out separately and usually is not included when amino acid analysis data are reported. In this project total and digestible tryptophan concentrations of 52 samples involving 16 ingredients and including all the major feedstuffs used in the poultry industry have been determined. Coefficients of apparent ileal tryptophan digestibility range from 0.48 for feathermeal to 0.88 for sunflower meal with values of 0.76 and 0.83 for sorghum and wheat respectively.

Project Title	Enhancing mucosal immunity in chickens by novel in-ovo and postnatal vaccination techniques
RIRDC Project No.:	US-72A
Start Date:	1/01/99
Finish Date:	31/12/01
Researcher:	Prof Alan Husband
Organisation:	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.au
Objectives	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:	Research work has focussed on the delivery of exogenous sources of cytokines (regulators of the immune system), to induce increased IgA antibody secretion. IgA acts as the first line of defence against pathogens present at the intestinal surface. To date, cytokines have been utilised whose mammalian counterparts upregulate IgA (interleukin-6 (IL-6)) or which have facilitated improved protection from coccidiosis (chicken interferon-gamma (ChIFN-g)). ChIFN-g protein or porcine IL-6 protein (obtained from CSIRO Animal Health, Geelong) were delivered in-ovo, into the amniotic cavity at 18 days of embryonation. Upregulation of IgA antibody in chicks hatched from these treated eggs will be determined during the first three weeks posthatch. Total IgA antibody in serum will be determined via ELISA and enumeration of the IgA secreting plasma cells in the intestine and spleen will be determined using immunofluorescence. Alterations in endogenous expression of cytokine transforming growth factor-beta (TGF- b ), which has a strong correlation with the production of IgA antibody, will be measured in spleen and caecal tonsils using reverse transcription polymerase chain reaction. Animal experimentation for this study has been completed and all samples have been collected. Sample analysis and evaluation of results is in progress.

Last updated: 6 September 1999
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