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

• Main Authors: Rollin, Xavier, Wauters, Jean-Baptiste, Bodin, Noelie, Larondelle, Yvan, Ooghe, Wilfried, Wathelet, Bernard, Abboudi, Tarik
• Other Authors: UCL - AGRO/MILA - Département des sciences du milieu et de l'aménagement du territoire, UCL - AGRO/BAPA - Département de biologie appliquée et des productions agricoles
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2006
• Subjects: Amino Acids; Animal Feed; Animals; Dietary Proteins; Dose-Response Relationship; Drug; Histidine; Isoleucine; Lysine; Nutritional Requirements; Salmo salar; Threonine; Weight Gain; Atlantic salmon
• Online Access: http://hdl.handle.net/2078.1/10478

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 degrees C. Doses of Thr represented 1, 31, 41, 51, 62, 72, 83 and 93 % of its ideal level for optimum protein deposition. Indispensable amino acids other than Thr were included in the same proportion (on a g/16 g N basis) as in the Atlantic salmon fry whole-body carcass. Following 36 d of feeding and a 36 h 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 5.4 mg Thr/kg body weight0.75 per d. The Thr maintenance requirement was 7.2 mg/kg body weight0.75 per d and the Thr requirement for growth was 66 mg for 1 g 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.