Feed Management - January 2012 - 25
| million metric tons of fish meal annually, up from 1 million metric tons in 1995. "If we don't change the amount of fish meal used, we will use everything in the world in four years," Hardy says. Fish meal and soybean meal prices 1500 New markets Another force driving the push to find fish meal alternatives are niche consumer markets. "I believe we will see a whole category of diets based on consumer demand," Hardy says. Barrows is working with one producer who wants to feed diets that are formulated without fish meal or fish oil. Bioalgals may meet that target, but could increase the feed cost from $0.50 a pound to $2.50 a pound. 1000 Fishmeal 500 Soymeal 0 Dec 02 Dec 03 Dec 04 Dec05 Dec06 Dec07 Dec08 Dec09 Since 2002, fish meal prices have nearly tripled while soybean meal prices have remained relatively steady. Feed samples the BFTC has made this year. The samples are different colors because of the feed ingredients being tested. Production systems are also impacting feed formulation. Solids - and how those solids stick together - can create a management problem for producers with re-circulative systems. Identifying alternatives While identifying alternatives for fish meal has been a priority in aquaculture feeds research for many years, Barrows said the problem is actually greater than that. "We don't just need alternatives for fish meal," he explains. "We really need more good ingredients." Barrows and his team have evaluated many ingredients over the last seven years and many more are scheduled for 2012. He uses a six-step process to evaluate all ingredients. There are so many companies hawking alternative products to the aquaculture industry - from biofuel algae to "insect meals" - that he had to formalize the process. "All of these ingredient suppliers see the void from fish meal," he says. Many want to rush straight to feeding trials, but Barrows begins by looking first at the compositional analysis to identify both nutrients and anti- January/February 2012 | WATTAgNet.com nutrients in the ingredients. Soy meal, for example, is high in protein but can cause enteritis in fish. Palatability and digestibility of the alternative are also considered. "If a trout won't eat an ingredient, a salmon won't even be in the water with it," Barrows says. Digestibility is evaluated by the amount of nutrition the fish derive from the ingredient. Functionality is also a priority. How does the ingredient affect the feed manufacturing process? How much energy does it require to make? Camelina, for example, holds promise for fish diets but is sticky and can gum up the pelleting process. Paying less for a raw ingredient that will cost the feed manufacturer considerably more to pellet won't benefit feed mills or aquaculture producers. Ingredients that pass the analytical tests are included in fry feeding trials to screen those with potential from the rest. Then, and only then, do rigorous feeding trials begin. Barrows compiles his data through the USDA ARS Trout-Grains Project website. Alternatives from biofuels Many of the alternatives Barrows and his team are evaluating are byproducts from the biofuels industry. Biofuel algae, ethanol yeast and high protein dried distillers grains are all showing potential. "We need these alternative feed ingredients, it's the only way we're going to get around these volatile feed prices," says Wendy Sealey, a researcher with the U.S. Fish and Wildlife Service. "But we need to know what's in it." Her research efforts have focused on calculating how much of each component in these alternatives are actually available to trout. "The numbers by themselves don't mean much," she says. "We need to know how much is available to trout." Zinc and copper are naturally high in fish meal, and researchers are learning how important those micronutrients are to aquaculture production. Micronutrient deficiencies are often the reason why a fish fed a plant-based diet does not perform as well as one fed a fish meal-based diet. Importance of phosphorus Researchers are finding that phosphorus is more important than once believed. One advantage of feeding fish a grain-based diet is it reduces the amount of phosphorus in the fish waste, and can help aquaculture producers meet water pollution goals. But, grain-based fish diets can also cause fish to have diarrhea, which makes removing fish waste from water more difficult. Feeding dried distillers grains may be a way for aquaculture producers to add phosphorus back to the diet in a form that is more digestible and meets the fish's nutritional needs without fouling water supplies. For all of the research going into developing new ingredients for the aquaculture feed industry, Barrows says the ideal fish feed is simple to describe: "It's whatever is cheapest and that the fish will grow the fastest on." [FM] 25
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