“In human food production realm, fish production provides another option to utilize South Dakota’s agricultural resources for economic development,” said professor Michael Brown, a scientist in SDSU’s Department of Natural Resource Management.
Brown’s latest work finds that some diets using soy protein concentrates, or SPC, perform as well as fishmeal-based diets.
That’s also good news for a hungry world and the world’s ocean fisheries, because production of aquafeeds needed to supply fish farming operations has nearly tripled in recent years, from 14.4 million U.S. short tons in 2000 to 41 million tons in 2010.
“The marine resources necessary to economically support that growth in aquaculture feeds and commercial production of fin fishes, etc., is not sustainable. Given the limited available supply and cost of fish meal and oils, plant-derived replacements are going to be highly valued in the marketplace,” Brown said.
That will give soybean and corn producers opportunities to add value to their crops, said Brown, who uses soybean meal, soy protein concentrates, and corn-based, dry distillers grains with solubles (DDGS) as primary ingredients in his experimental fish diets.
“The latest trials we’ve completed have compared SPC as fishmeal replacers in feeds for rainbow trout and yellow perch. We’ve done these trials with and without amino acid supplements to determine the effects on growth performance, fillet composition and other basic metrics that we use to determine how well a feed is performing,” Brown said. “Recently some of the SPC and DDGS diets that we’ve tested have yielded even better growth than what we saw with fish meal and DDGS controls.”
In a yellow perch feeding trial, one of the SPC diets tested without amino acid additions produced lower weight gain (20 percent) than the control diet (60 percent). However, with amino acids, SDSU researchers achieved the same level of growth performance (60 percent weight gain), Brown said. A different SPC product clearly outperformed fishmeal.
“Combined with selected supplements, that product provided a 175 percent weight gain, and without the amino acid supplements, it did just a touch better (80 percent weight gain) than our fishmeal control,” he said. These results reveal some of the variability that exists in SPC products.
There are several SPC products on the market and soybean processing technology will advance to provide others having different composition and nutritive value. Similarly, with changes occurring in the biofuel industry, alterations in the chemical profiles of corn co-products will occur. Brown’s ongoing work explores how well they perform in fish diets.
“In essence, the idea is, how far can we push soybean and corn products and co-products as diet constituents and still maintain or obtain better performance than we do with the marine-derived fishmeal diets.”
Brown said finding alternative, sustainable feeds to commercially raise fish will be critically important in future decades as the population of humans is expected to near the 9 billion mark. Fish are more efficient at converting feed than any land-based livestock, including poultry and swine, their closest competitors in feed conversion efficiency, Brown said.
“When you think about it, it makes sense. You have fish in this aqueous solution, in water. They require less skeletal support — it’s basic physics,” Brown said. “They require less energy to maintain their position in that medium. Even though there’s higher resistance there due to the viscosity, they also tend to move slower and use less energy. They’re also poikilotherms, so they don’t generate their own body heat — that’s less metabolic energy required to cool or heat themselves. These are some of the primary underlying reasons for the conversion efficiency. They simply make more efficient use of their food.”
The South Dakota Soybean Research & Promotion Council has played a key role in supporting Brown’s research. In addition, the U.S. Department of Agriculture has been funding the DDGS research. The South Dakota Agricultural Experiment Station also supports Brown’s aquaculture studies.
Lance Nixon | Newswise Science News
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Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
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Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
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Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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