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Replacement of fish meal with a matrix of organic plant proteins in organic trout (Oncorhynchus mykiss) feed, and the effects on nutrient utilization and fish performance

Lund, Ivar; Holm, Jørgen; Rasmussen, Hanne T.; Dalsgaard, Anne Johanne and Jokumsen, Alfred (2011) Replacement of fish meal with a matrix of organic plant proteins in organic trout (Oncorhynchus mykiss) feed, and the effects on nutrient utilization and fish performance. [Erstatning af fiskemel med en matrix af økologiske planteproteiner i foder til økologiske ørreder (Oncorhynchus mykiss) og effekter på næringsstof udnyttelse og vækst.] Aquaculture, 321 (3-4), pp. 259-266.

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Online at: http://www.sciencedirect.com.globalproxy.cvt.dk/science/article/pii/S004484861100754X

Summary

This study examined the effects on nutrient utilization and fish performance when replacing 16, 31, and 47% of fish meal protein (corresponding to replacing 15, 29 and 44%, respectively, of total dietary protein) with a fixed matrix of organic pea, horsebean and rapeseed plant protein concentrates (PPC) in a ratio of 1.07:1.00:0.66. Four iso-energetic and iso-nitrogenous diets were produced to include 0, 136, 274 or 410 g kg-1 of the organic PPC matrix, respectively. The organic protein ingredients were chosen based on their high protein content, and the matrix was established to mirror the amino acid composition of fish meal. The plant ingredients were dried, dehulled, grinded and air classified in accordance with the European Union Commission Regulation on organic aquaculture production, increasing the protein concentrations up to 577 g kg-1 dry matter. Two experiments were carried out using juvenile rainbow trout (Oncorhynchus mykiss): 1) a digestibility study to examine the apparent digestibility of protein, lipid, nitrogen-free extract (NFE), total phosphorus and phytate-phosphorus, followed by a water sampling period to determine the output of nitrogen and phosphorus and enabling the setup of nitrogen and phosphorus mass-balances; and 2) a 57 days growth study including 3 growth periods each of 19 days and using pit-tagged fish. Substituting fish meal with organic PPC significantly increased the apparent digestibility coefficient (ADC) of protein and lipid (P<0.008) at the highest PPC inclusion level, while there was a significant (P<0.044) decrease in the ADC of NFE with increasing PPC inclusion level. The apparent digestibility coefficient of phytate-phosphorus was significantly lower (P<0.005) at the highest PPC inclusion level compared to the fish meal control diet. The mass-balances revealed a significant increase in the excretion of ammonium-nitrogen (NH4N, P< 0.017) at the two highest PPC inclusion levels and a decrease in phosphorus (P<0.009) excretion at the highest organic PPC inclusion level. There was no overall effect on the specific growth rates (SGRs) or feed conversion ratios (FCRs). The study thus demonstrated that it is possible to replace fish meal by 47% organic PPC without compromising rainbow trout performance. However, the results also indicated that it will be difficult to replace much more than this as long as supplementation with synthetic amino acids and exogenous phytase is not allowed in organic feed.

Summary translation

I dette studie undersøgtes effekter af at erstatte henholdsvis 16, 31, og 47% af fiskemels protein( svarende til henholdsvis 15, 29 og 44% af total proteinet i diæten)med en konstant matrix af økologisk ærte-, hestebønne- og raps-protein-koncentrater, på næringsstofudnyttelse og vækst hos økologisk regnbueørred. Ved de højeste inklusioner af planteproteinkoncentrat (PPC) fandte sign. højere fordøjelighed af protein og fedt, mens kulhydratfordøjeligheden og fordøjeligheden af fytat-fosfor faldt sammenlignet med fiskemels-kontrollen. Tilsvarende viste høj PPC-diæterne øget udskillelse af ammoniak-kvælstof og mindre udskillelse af fosfor. Vækst og foderudnyttelse var stort set ens for alle undersøgte diæter. Forsøget indikerede at grænsen for erstatning af fiskemel var nået, idet begrænsningen sås i opnåelse af aminosyrebalance og fosfortilgængelighed.

EPrint Type:Journal paper
Keywords:organic, rainbow trout, plant protein, nutrient utilization, N, P
Subjects: Food systems > Recycling, balancing and resource management
Farming Systems > Farm nutrient management
"Organics" in general > Country reports
Research affiliation: Denmark > DARCOF III (2005-2010) > ORAQUA - Organic fish production
Denmark > DTU - Technical University of Denmark
ISSN:0044-8486
DOI:doi.org/10.1016
Deposited By: Jokumsen, Senior Advisory Scientist Alfred
ID Code:19714
Deposited On:30 Nov 2011 13:33
Last Modified:03 Jul 2012 12:18
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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