Microbial-mediated increase in phosphorus availability from animal protein-based ingredients fed to rainbow trout
Fish feeds contain a fraction of unusable phosphorus that is excreted by fish. By making this fraction available to salmonids, the phosphorus concentrations of feeds could be smaller, which will result in a reduction in phosphorus discharges. A number of naturally occurring soil microorganisms, including some fungi and bacteria, are recognized as having properties that dissolve phosphorus. Several of these microorganisms have even been commercialized and are currently used as soil inoculants to increase phosphorus availability, thereby increasing the yield of harvests. The inclusion of these microorganisms in fish feed may operate in a similar manner and may increase the phosphorus availability of food sources containing moderately soluble phosphorus. The objective of this project is to use soil microorganisms capable of dissolving phosphorus to improve the phosphorus availability of animal protein sources. Tests will consist of incorporating a microorganism already used in agriculture that is capable of dissolving the unavailable fraction of phosphorus found in animal protein-based feeds.
This project should make it possible to formulate an experimental feed after determining the optimal levels of animal meal and microorganisms to incorporate. The improvement of the digestibility of the ingredients used in the formulation of this feed for salmonids should result in a reduction in suspended solids and nutrients in fish farm effluents.
2002 - 2005
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