SCRC: PDRS - Seafood Molecular Biologist: Mapping Microbial Communities in Seafood Production and Processing Environments to Improve Targeting Intervention Strategies (Dr Shane Powell)
Microbial species negatively impact animal health, product spoilage and safety. The best approach to reduce these unwanted effects is to precisely define the species that reduce product quality, determine the sources of contamination, and then target the best intervention strategy(s) where it is required. The reason this research is needed is that the historical approach to solving these problems has been to isolate and identify bacteria using culture-based methods, based on the assumption that all bacteria that reduce product quality can be isolated on agar media. We now know that culture methods only show a small percentage of the bacteria that are present in food and other environments. Therefore we propose to use a well-tested direct-detection DNA-based method that will provide a more complete profile of microbial contamination, identify the species that cause the problem, and assist in designing strategies to produce a solution.
Final report
Until the 1990s, when it became possible to access and analyse DNA directly from the environment, the study of microbiology was limited to studying microbes that were able to be grown in artificial culture. The advent of DNA-based methods provided a way to access and study the enormous diversity of microbes that actually exist. Some fields of microbiology were quicker to take up this technology than others. Microbiological analyses carried out in industrial settings have, although this is changing, remained culture-based because they are standard methods required by regulators. They tend to be technically straight-forward and inexpensive. The goal of the Seafood Molecular Biologist position was to apply DNA-based techniques to a range of existing problems within the seafood industry. The three projects developed covered shellfish aquaculture, the processing of Atlantic Salmon and supply chains in the wild prawn fishery.
SCRC: GM Program budget
SCRC: Higher Education Theme Leader & VET Theme Leader budget
Seafood CRC: Planning, implementation and commercialisation of the Australian prawn farming industries five year R&D Plan
Australia's prawn farmers have developed a five year R&D plan through rigorous consultation throughout the industry and with other stakeholders, such as R&D providers and funding agencies.
As a result Australian prawn farmers have identified their primary objective from investment in R&D is achieveing growth in an economic and environmentally sustainable manner.
They aim to do this by investing to increase the industries average production from 4t/ha to 8t/ha, increasing the farm gate value of farmed prawns from $14/kg to $16.50/kg whilst continuosly improving environmental management.
The R&D required to underpin achievement of these objectives has been broken down into three programs:
1. Improving domesticated broodstock
2. Improving prawn farm productivity
3. Improving farmed prawn market value
As such industry support for project development is based on both proposed new projects and existing projects contributing to achieveing these objectives.
Within the Seafood CRC industry involvement in project planning and review is considered a must, as is maintenance of the relevance of the R&D strategy. The Executive Officer position will be responsible for achieving this under the direction of the APFA Executive Committee.
SCRC: PhD : Quality, shelf-life and value-adding of Australian oysters
This project will contribute to work that will fulfill critical CRC Milestones. There is potential that the work will result in a direct increase in the value of Australian oyster production by value adding existing products.
The Australian Seafood CRC has previously identified building capacity in the area of seafood processing is a high priority for the CRC. This project will make use of and contribute to the collaborative links (to be developed) with the UK based Grimsby Institute.
The project will develop Australian capability and capacity in value adding of products that will be applicable to many areas of the CRC. This will be critical to the Australian seafood processing industry being able to deliver innovative seafood products which are of high eating quality.
SCRC: PhD : The effect of temperature on reproductive development in maiden and repeat spawning farmed Atlantic Salmon: Understanding the molecular basis for improved egg quality and survival
The economic viability of sea cage farming of Atlantic salmon is strongly influenced by the cost of
production of smolts. Understanding the mechanisms that contribute to, or cause reproductive failure in
spawning fish is an essential component of reducing those industry production costs, and at a broader
level, ensuring that there are sufficient smolts produced each year to maintain industry production. The
issue has been identified as an industry priority with the stated SALTAS aim of reducing the reliance on
repeat spawning fish for egg production. The potential cost of failing to solve the problem is high. The
survival of eggs to the eyed embryo stage can be as low as 30-50%, compared with 80% for eggs from
best performing fish (SALTAS data). Modelling of this cost gives direct increases in smolt production
costs of $225,000 per annum, but a potential industry shortfall in production terms of $15-20 million per
annum.
The knowledge gained through this research will be applied in a real life context to the Atlantic salmon industry in Australia to overcome a real and immediate industry bottleneck, and provide information to assist in large scale production procedures. It will provide important new information regarding the endocrine regulation of egg quality, information that could be highly relevant to other finfish industries, such as tuna and kingfish.
In addition to the direct benefit of this research to the Salmon industry, the investigation of the impact of temperature on reproductive process in fish is relevant to environmental studies concerning the impact of global warming on biological processes, with the Atlantic salmon being an example of a fish that has been translocated from a colder environment (Europe) to the warmer Tasmania.
Final report
Tasmanian Atlantic Salmon (Salmo salar) broodstock can encounter temperatures above 20°C, which has a marked negative effect on reproductive development. Broodstock management strategies are needed in order to maintain egg quality in the face of thermal challenge either due to seasonal fluctuation or climate change, where temperatures are expected to rise even further. In Tasmania, the Atlantic Salmon industry uses maiden fish for approximately 75 % of egg production due to their smaller size and the lower cost associated with their husbandry relative to repeats. However, maidens appear to be more susceptible than repeat fish to the effects of elevated temperature. The salmon industry's ability to cope with rising temperature is hindered by the lack of understanding of the effects of thermal challenge on the endocrine system, which ultimately determines egg quality.
Therefore the aims of the research were to:
- Determine how temperature influences endocrine function and reproductive development in maiden and repeat spawning female Atlantic Salmon;
- Understand the molecular mechanisms that determine egg quality in broodstock maintained at elevated temperature; and
- Develop management strategies to maintain endocrine function and egg quality under thermally challenging conditions
The research provided evidence that female maiden Atlantic Salmon are more susceptible to the effects of elevated temperature and that thermal impairment of endocrine function occurs at multiple levels of the reproductive axis. Treatment with various hormonal therapies showed mixed results and suggest that it is difficult to overcome the impacts of higher temperature on the reproductive axis using a single hormonal treatment. Hormonal therapies in the future should simultaneously stimulate vitellogenesis and zonagenesis in order to maintain egg quality. It is evident that the method of hormonal delivery is of considerable importance and implantation techniques also warrant further investigation.
SCRC: PhD : Increasing Oyster Spat Production Through Management of Microbiological Contamination
Vibrio species are a notorious pest in all aquaculture systems, producing significant losses in productivity. However, the problem still persists today because the causative agents and associated virulence factors have not been adequately identified and, because little is known about environmental conditions that cause the pathogen(s) to proliferate. Supply of oyster spat is currently failing to meet demand consistently in Australia, with Australian hatcheries only producing seed for the local market of approximately 250 million a year compared to a world market in excess of 10 billion oyster seed. Solving this problem will allow Australian oyster hatcheries to design and implement effective risk management systems, thus increasing supply to expand national and international markets. In addition, the aquaculture industry needs greater human capability and capacity to manage disease in aquaculture operations.
Relevance to industry priorities and Seafood CRC milestones
The associated Program and theme is within Production Innovation – Program Manager Dr Graham Mair - Outcome: Increased profitability and industry value through production innovation.
Specific output and associated milestones include:
1.3 Output: Removal or reduction of key production constraints in selected aquaculture systems
1.3.3 Milestone: Strategic disease management approaches and technologies developed for at least two aquaculture species
1.3.5 Milestone: Production efficiency gains from genetic, health management and nutritional interventions quantified to inform long-term strategies and estimate commercial benefits