46 Fish as feed inputs for aquaculture – Practices, sustainability and implications
with high proteolytic activities in the guts of the fish also contributes strongly to the
rapid degradation often seen in small pelagic species. The high catch rates also mean
that fish to be used for human consumption must be landed, chilled and processed
in large quantities, and they must be handled rapidly. Much research was carried out
in the 1980s in the United States of America into the use of menhaden for surimi,
but uptake was limited, because it was not possible to de-fat the flesh to achieve a
shelf-stable product without affecting the taste and texture of the flesh. The Nordic
Industrial Fund supported a Nordic network project entitled “Pelagic fish – New
Possibilities” during the period 1998–2001 that collated technical, scientific and
industrial information about the catching and processing small pelagic fish with the
specific aim of facilitating diversification of small pelagic fish products, especially for
direct human consumption. There has also been extensive private-sector interest in
developing processing techniques to both stabilize small pelagic material and to extract
the main protein components for use in more versatile forms such as surimi.Greater substitution with protein and oil substitutes
The potential for including higher levels of non-fishmeal protein in aquafeeds has been
explored for a number of years with gradual but significant success.
As discussed earlier, the proportion of oilseed and legume-derived meals in aquafeed
will increase from 17 percent to 24 percent by 2010, resulting in the reduction in the
use of Northern Hemisphere fishmeal, while vegetable oils will become an important
source of oil in salmonid, accounting for nearly a quarter of the oil content by
2010, again resulting in the reduction in the use of Northern Hemisphere feed-fish
supplies.’
Research is currently being conducted by the major aquafeed manufacturers in
Europe and is being supported by research initiatives from both individual governments
and the EC. Current or recent initiatives of interest include:- Perspectives of Plant Protein Use in Aquaculture (PEPPA) project: This was a
€2.5 million (US$3.5 million at current rate of exchange) project over 2001–2004
to (i) replace the greater amount of fishmeal with plant protein sources in fish
diets while improving muscle protein growth, fish quality, health, reproductive
potential and environmental quality; (ii) understand the metabolic fates of dietary
amino acids and carbohydrates as carbon donors and as an energy source; and (iii)
strengthen our understanding of the relationships between nutritional factors and
endocrine control of muscle growth and adiposity using cellular and molecular
approaches. - Researching Alternatives to Fish Oils in Aquaculture (RAFOA): This EU-funded
project is studying the effect of substitution of fish oils with plant oils on growth
performance, fish health and product quality during the entire life cycle of salmon,
rainbow trout, seabream and seabass. - The Directorate of the Fisheries Institute of Food and Nutrition in Norway has also
conducted similar research to that of the RAFOA project. In addition, a second
project, “Fish Oil Substitution in Salmonids” (FOSIS), is currently investigating
whether fish oil can be replaced by vegetable oils in the diet without reducing
the nutritional value or the growth performance of the fish, while minimizing fat
deposition in the flesh. - Two EU research projects are studying the effects of plant oils on fish digestion
and metabolism, “GLUTINTEGRITY” and “FPPARS”. In addition to vegetable
oils, an EU research project “PUFAFEED” is investigating the use of cultivated
marine micro-organisms as an alternative to fish oil in feed for aquatic animals.