Turning the spotlight on fishmeal alternatives, a new FAO report outlined the latest developments in sustainable fish feed supplies.
Global seafood consumption topped 100 million metric tons in 2001 and is predicted to rise by an additional 65 million metric tons by 2030. But it is widely accepted that wild fisheries will be unable to meet such demand, leaving aquaculture to potentially make up for the shortfall. And, many argue, the key to sustainable aquaculture will be in successfully reducing the reliance of farmed fish on fishmeal and oil sourced from wild fish.
The FAO report cited the reduction in the dependency of fishmeal and oil drawn up by RAFOA (Alternatives to Fish Oil in Aquaculture), coordinated by the University of Stirling in Scotland. According to the project, inclusion of fishmeal and fish oil in feed for Atlantic salmon is currently from 35 to 47 percent and 25 to 33 percent, respectively.
The RAFOA has targeted 12 to 16 percent for fishmeal and 8 to 12 percent for fish oil. Additional targets have been drawn up for rainbow trout, sea bream and common carp. In fact, the project has targeted zero inclusion for fishmeal and oil for carp, levels that currently stand between 20 and 25 percent for fishmeal and 5 to 10 percent for oil.
“It has been established that blends of vegetable oils can replace fish oil for the major part of the growth period in several farmed fish — Atlantic salmon, rainbow trout, European sea bass and gilthead sea bream,” said the FAO.
The agency also cited findings from Aquamax, an initiative funded by the European Commission, with 32 partners. The project’s aim is to replace “as much as possible” of the fishmeal and oil currently used in fish feeds with sustainable, alternative feed resources. Vegetable oils have been blended to mimic the levels of total saturated, monounsaturated and polyunsaturated fatty acids in fish oils and their high levels of omega-3 polyunsaturates, except that of the C18 linolenic acid (18:3w3).
Further research, said the FAO, is investigating biological enhancement through micro-organisms, such as yeast, bacterial and fungal fermentations, to determine their capacity to reduce the effects of anti-nutrients in plant materials. According to the report, the goal is to “increase protein concentration and decrease the levels of anti-nutrients.”
In terms of alternative protein sources to fish, innovative new protein sources are mainly focused on microbial and algal species. But, warned the FAO, cost of production will be an issue with most of the manufacturers of microbial proteins.
The FAO reported that an Asian firm is currently developing a microbial product that is garnering “considerable interest” from Asia’s largest integrated feed company, Charoen Pokphand Group Thailand. “It will be interesting to see the uptake of this type of product in the aquafeed sector when commercialized in the near future,” said the agency.
In addition to plankton, other invertebrates used as protein sources to replace fishmeal are polychaete worms and terrestrial insects. Polychaetes include both marine worms and earthworms.
“These worms are a potentially valuable source of protein, if they can be produced and processed economically,” said the FAO.
In terms of land insects, silkworm pupae, which contains a high content of free fatty acids, is also being used.
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