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Maintenance threonine requirement and efficiency of its use for accretion of whole-body threonine and protein in Atlantic salmon (Salmo salar L.) fry

Published online by Cambridge University Press:  08 March 2007

Rollin Xavier*
Affiliation:
Laboratoire de Pisciculture M. Huet, Université catholique de Louvain, Route de Blocry, 2, B-1348 Louvain-la-NeuveBelgium
Jean-Baptiste Wauters
Affiliation:
Laboratoire de Pisciculture M. Huet, Université catholique de Louvain, Route de Blocry, 2, B-1348 Louvain-la-NeuveBelgium
Noélie Bodin
Affiliation:
Laboratoire de Pisciculture M. Huet, Université catholique de Louvain, Route de Blocry, 2, B-1348 Louvain-la-NeuveBelgium
Yvan Larondelle
Affiliation:
Unité de Biochimie de la Nutrition, Université catholique de Louvain, Croix du Sud, 2/8, 1348 Louvain-la-Neuve, Belgium
Wilfried Ooghe
Affiliation:
Laboratorium voor Bromatologie, Universiteit Gent, Harelbekestraat 72, 9000 Gent, Belgium
Bernard Wathelet
Affiliation:
Unité de Chimie Biologique Industrielle, Faculté universitaire des sciences agronomiques, Passage des Déportés, 2, B-5030 Gembloux, Belgium
Tarik Abboudi
Affiliation:
Laboratoire de Pisciculture M. Huet, Université catholique de Louvain, Route de Blocry, 2, B-1348 Louvain-la-NeuveBelgium
*
*Corresponding author: fax +32 10 474991, email [email protected]
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Abstract

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Eighteen groups of seventy Atlantic salmon (Salmo salar L.) fry (initial mean body weight 0·8 (sd 0·01) g) were fed on semi-purified diets containing graded levels of l-threonine (Thr) in 15 litres aquaria at a temperature of 14·5±1°C. Doses of Thr represented 1, 31, 41, 51, 62, 72, 83 and 93% of its ideal level for optimumprotein deposition. Indispensable amino acids other than Thr were included in the same proportion (on a g/16g N basis) as in the Atlantic salmon fry whole-body carcass. Following 36d of feeding and a 36h fast, fry were killed for whole-body protein and amino acid analysis. Weight gain (r2 0·98), protein accretion (r2 0·97), and Thr accretion (r2 0·97) were linear (P<0·01) functions of Thr intake. Slope of the Thr accretion regression line showed that the efficiency of Thr utilisation above maintenance was 76%. At zero Thr intake, fry lost 5·4mg Thr/kg body weight0·75 per d. The Thr maintenance requirement was 7·2mg/kg body weight0·75 per d and the Thr requirement for growth was 66mg for 1g protein deposition. Increasing doses of Thr resulted in increased (P<0·05) concentrations of histidine and lysine, and decreased concentrations of isoleucine in whole-body protein. The maintenance need for Thr represented 13·4% of the total need for Thr. The data suggest that efficiency of Thr utilisation above maintenance is constant at all levels of Thr intake between 1 and 93% of the level required for optimum protein deposition.

Type
Research Article
Copyright
Copyright © The Nutrition Society 2006

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