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Organic vegetable proteins and oil in feed for organic rainbow trout (Oncorhynchus mykiss)

Lund, Ivar; Dalsgaard, Johanne; Larsen, Bodil and Jokumsen, Alfred (2010) Organic vegetable proteins and oil in feed for organic rainbow trout (Oncorhynchus mykiss). [Økologiske planteproteiner og planteolie i foder til økologiske regnbueørreder(Oncorhynchus mykiss).] Poster at: XIV International Symposium on Fish Nutrition and Feeding, Qingdao, China, May 31 – June 4 2010 .



The demand for organic trout is increasing, stressing the need for organic, vegetable feed ingredients as replacement for fish meal, as the principles of organic aquaculture encourage the development of feed that do not deplete global fish stocks. In addition, the organic code of practice does not allow addition of artificial amino acids to the feed, and optimization of the amino acid profile of organically based diets must therefore derive from the protein sources alone.
The aim of this study was to evaluate the digestibility and growth performance of organic vegetable dietary ingredients as replacement for fish meal and fish oil in feed for organic rainbow trout (Oncorhynchus mykiss).
Six iso-energetic and iso- nitrogenous diets were prepared, comprising a fish meal and fish oil based control diet and three diets in which the inclusion of fish meal was gradually reduced from 59 to 35 % and replaced by a matrix of organic horse bean, pea and rape in the proportion of 1:1:0.7. In the last two diets, the inclusion of fish oil was reduced by 50 and 100 %, respectively and replaced by flax seed oil high in omega-3 fatty acids.
Digestibility was measured directly using a modified, flow-through Guelph System consisting of 18 tanks, and feeding each diet in triplicate. Growth performance was measured using a recirculation system consisting of 12 square formed fibre glass tanks. The fish were reared in duplicate for 9 weeks, from an initial individual weight of about 60 g to a final weight of about 200 g.
The fish showed good growth performance with a specific growth rate (SGR) of 1.8 % d-1, and a feed conversion ratio (FCR) of 0.75, and there were no significant differences between the groups. In contrast, there were significant differences in the digestibility of protein, lipid and especially NFE in fish fed diets with organic protein concentrates. For fish fed diets with organic oils, the digestibility of oil was significantly higher in fish fed 100 % flax seed oil.
The results indicate that a matrix of organic horse bean, pea and rape may partially replace fish meal, and flax seed oil may replace fish oil in feed for organic rainbow trout without compromising growth performance and feed utilization.

Summary translation

Efterspørgslen efter økologiske ørreder er stigende, og dermed øges presset på økologiske vegetabilier til delvis erstatning af fiskemel og fiskeolie i foderet.
Formålet med studiet var således at undersøge fordøjelighed og vækst hos økologiske regnbueørreder fodret med diæter, hvor fiskemel og fiskeolie var erstattet med økologiske vegetabilier.
Seks iso-energetiske og iso-nitrogene diæter blev fremstillet, herunder 1 kontrol diæt, 3 diæter hvor inklusionen af fiskemel blev gradvist reduceret fra 59 til 35 % og erstattet af en matrix af økologiske hestebønner, ærter og raps i forholdet 1:1:0.7. I de sidste 2 diæter, var inklusionen af fiskeolie reduceret med henholdsvis 50 og 100 %, og erstattet med hørfrøolie, der også har et højt indhold af omega-3 fedtsyrer.
Fiskene udviste god vækst med en specifik vækstrate (SGR) på 1.8 %/dag, og en foderkvotient på 0.75. Der var ingen signifikante forskelle mellem grupperne. Derimod var der signifikante forskelle i fordøjelighed af protein, fedt og især kulhydrat (NFE) hos fisk fodret med økologiske protein koncentrater. Hos fisk fodret med diæter med økologisk hørfrøolie var fedtfordøjeligheden signifikant højest i gruppen, hvor al fiskeolien var udskiftet med hørfrøolie.
Resultaterne antyder således, at en matrix af økologiske hestebønner, ærter og raps kan delvist erstatte fiskemel, og hørfrøolie kan erstatte fiskeolie i foder til økologiske regnbueørreder.

EPrint Type:Conference paper, poster, etc.
Type of presentation:Poster
Keywords:Rainbow trout, organic protein, organic oil, horse bean, pea, rape, flax seed oil, digestibility, growth, feed utilization.
Subjects: Animal husbandry > Feeding and growth
Knowledge management > Research methodology and philosophy
Farming Systems > Farm nutrient management
Research affiliation: Denmark > DARCOF III (2005-2010) > ORAQUA - Organic fish production
Denmark > DTU - Technical University of Denmark
Deposited By: Jokumsen, Senior Advisory Scientist Alfred
ID Code:17241
Deposited On:08 Jul 2010 07:34
Last Modified:06 Aug 2012 13:36
Document Language:English
Refereed:Not peer-reviewed

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