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Dr Alexandros Samartzis
Nutritional solutions for better health and sustainable aquaculture production he global aquaculture industry has undergone several transformations during the last decades, driven not only by health, nutritional and production challenges but also by consumer perceptions and market demands. The two main drivers are the rapidly increasing population and the growing demand for seafood. As aquaculture gets more intensive in order to cope with the global market demand, exposure and susceptibility to disease challenges are also increasing. In the particular case of the shrimp industry, since Litopenaeus vannamei was introduced to Asia and gradually replaced Panaeus monodon, the global shrimp production has reached new heights. Through the years a number of diseases such as; infection myonecrosis virus, acute hepatopancreatic necrosis disease and enterocytozoon hepatopenaei have caused a devastating reduction in production in most of the countries. Therefore, the threat of disease is a reality that the farmers have learned to live with. The global trend to restrict or ban the use of antibiotics in animal production, as well as the demand for more sustainable food production, has created the need for new management solutions and strategies to fight against the pathogens that the fish and shrimp are suffering from. In this context natural growth promoters and health solutions started gaining more interest and a place in the feed formulations. Probiotic, prebiotics, organic acids and yeasts etc have shown to provide solutions that can improve the health status, the nutrient utilization and consequently the performance of the cultured animals. More specifically, probiotics are increasingly becoming well accepted not only in animal nutrition but for humans too, as a prophylactic measure. Probiotics are generally defined as the live microorganisms which when administered
in adequate amounts, confer a health benefit on the host. These health benefits are achieved via the modulation of the intestinal microbiota as well as the immune system, increasing the resistance to infections and thereby enhancing the survival rates. Probiotics can be supplemented in feeds or directly applied in the water. They can either be used in preventive treatments or to treat pathogen-related disease but with the main focus targeting the gastrointestinal (GI) tract of the host. With many products available in the market with ranging applications and dose recommendations, it is very important to understand the species of the probiotic used and the characteristics of this bacterial as well as its mode of action against the pathogenic bacteria. For instance, one distinct mechanism of action that can be observed in selected probiotics and gaining more attention of the quorum quenching (disruption of quorum sensing). Quorum sensing is the microbial cell signalling, which allows microorganisms to sense its own population density and when the autoinducers (external signal) reach a threshold they synchronise processes such as bioluminescence, antibiotic production, conjugative DNA transfer, sporulation, virulence and biofilm formation to name a few. N-achylhomoserine lactone (AHL) is the best-known autoinducer and widely utilised by Gram-negative bacteria to adapt to changes in the environment. Selected probiotic strains of the Bacillus genus have shown to block the AHL and consequently the communication among the pathogenic bacteria. The understanding of the mode of action of the species as well as the stability (i.e. heat recovery in the extrusion process) and correct application of the products can elevate probiotics as an effective solution in disease prevention and health enhancement, paving the way for sustainable aquaculture practices.
Dr Alexandros Samartzis is the Senior Technical Service Manager for Evonik (SEA) Pte. Ltd. based in Singapore. He holds an MRes and PhD in fish nutrition from the University of Plymouth, UK. He also has an MBA from the Agricultural University of Athens, GR. 8 | February 2017 - International Aquafeed
Aquaculture growth and the soybean
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quaculture is at the centre of conversations beyond the circle of animal agriculture. As the fastest growing animal protein, the most common circle discussions are on soybean. The US Soybean Export Council and the Soy Aquaculture Alliance (SAA) have joined forces to host the 2017 Aquaculture Educational Opportunity in Panama City, Panama. US soybean growers, researchers and aquaculture experts gathered to take in latest and visit the Panama Canal to witness the centre of global trade and the important role US soy play in the international economy. Bridget Owen, SAA Executive Director, has devoted her career to the soybean community at various levels of the supply chain; she explains what this growth means. “We have incredible resources, allowing us to be competitive. Number one is our growers who produce high quality, consistent and cost effective products. We have incredible transportation resources and access to overseas markets, making a quick, secure and cost efficient transaction important to our customers. There are many ways US soy delivers domestically and internationally and our infrastructure is a part of that.” She added that the demand for seafood as a whole is growing exponentially; it’s the fasting growing food production sector and the fastest growing use of soy. “We would like to see more fish production, more shrimp production here at home. There are opportunities for that. Simply she adds, “we need more product and to feed the growth, more soy is needed.”