Introducción

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Aquaculture is a young sector which has been showing in recent years
an unstoppable, exponential and irreversible growth. This trend can only
continue as long as the supply of certain raw materials like fish oils and
meals, which are essential for the manufacturing of feed, may grow in line
with it. This is the only bottleneck for the future of aquaculture: fish oil
production is at a standstill. The massive and traditional sources of fish oil
have been based and in fact, they are still supported by the exploitation
of great biomass of marine species. These and many other fisheries are
nowadays technically declining and socially under question.

Fish meals and oils go through the same processing; both depend highly on
wild fisheries as Peruvian anchovy (Engraulis ringens) which are under a high fishing pressure. This situation together with other new phenomenon like climatic change could explain its stagnation or even recession. This would be completely negative for the aquaculture sector whose needs of fish oil for year 2030 are estimated at 40 million tonnes.
To consolidate the desired and rapid growth, aquaculture should base its
expansion in a greater diversification of the sources of raw material regularly used. This is not a new statement and it has been assumed a long time ago by the whole industry in this activity despite of some remarkable problems.
Thus there is a clear research line, not yet fruitful, focused on identifying
renewable (vegetal) sources of n-3 long chain polyunsaturated fatty acids
(n-3 LC-PUFA) as a partial alternative to fish oils. Likewise there are many
efforts addressed to obtain protein concentrates of vegetal origin with the
same purpose.
Apart from identifying and introducing alternative ingredients the
evolution of feed formulation to obtain the best nutritional profiles requires
unavoidably new additives. Additional problems such as high densities and
the subsequent risk of disease transmission; limited and even forbidden
use of antibiotics; together with feed with a high vegetal content, lead to
a reduction in survival and growth as well as a lower efficiency in feed use.
All these disturbances make aquaculture activities not very profitable. In
order to promote growth and an adequate health condition there are several useful tools to be used. Some of them are: the inclusion of natural growth promoters in feed, the use of lactic bacteria to enrich cultures of Artemia and rotifers in hatcheries, as well as the combination of mineral vitamin markers with immune stimulant activity. Many of these substances have shown to affect certain species causing benefits derived from their antimicrobial effects, effects on the development of the intestinal epithelium, antiinflammatory or digestibility improver.
5 Economically speaking the great price variation in feed ingredients and the low market prices for products from aquaculture, challenge the benefit of many aquaculture activities around the world. As production costs increase, nutritionists look for new ways to reduce them, maximizing digestive and metabolic activities as a base to turn nutrients in growth. Additives to increase digestibility have the ability to improve the use of nutrients from economical ingredients and encourage their transformation in food/meat.
They also cause a reduction of fat accumulation in muscle and guts.
The Centro Tecnológico del Mar-Fundación CETMAR organized on the 29th
September 2011 a seminar titled “Use of New Additives in Fish Feeds”
about the relevant role of technological additives and vegetal ingredients
in feed formulation (seminar organized within ZIMOFEED project
PGIDIT08MMA003CT, financed by Tecnoloxía Sectorial MMA Program,
Consellería de Economía e Industria). The seminar aroused a great interest
and had a remarkable reception. All along the event the audience showed a
great interest about the subject. Thus, the idea of publishing this book was
born to collect all the information released during that seminar in a way that all the different issues involved nowadays in this subject were represented.
Obviously, the intention is to serve as an orientation to those who want to
study in depth these applied aspects of aquaculture research and nutrition.
This book would not have come true if we had not counted on the selfless
help of a number of professionals and companies. We could not have reached our goal without their generous contribution. Especially we must mention the following companies DIBAQ SA, NUTRIAD and NOREL SA whose firm commitment with aquaculture has make this book possible. We are in debt with all scientists and company representatives who have given shape to the book as well as to the seminar. To all of them we thank from these pages for their altruistic effort and compromise and confirm our gratitude and recognition.

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