Digestibility and nitrogen utilisation of diets containing protein at different levels and supplemented with dl-methionine, l-methionine and l-lysine in blue fox ( Alopex lagopus)

• Published in: Animal feed science and technology 2002-08, Vol.98 (3), p.219-235
• Main Authors: Dahlman, Tuula, Kiiskinen, Tuomo, Mäkelä, Jaakko, Niemelä, Paavo, Syrjälä-Qvist, Liisa, Valaja, Jarmo, Jalava, Taina
• Format: Article
• Language: English
• Subjects: Amino acids; Animal productions; Biological and medical sciences; Blue fox ( Alopex lagopus); Fundamental and applied biological sciences. Psychology; Low protein; N excretion; N retention; Terrestrial animal productions; Vertebrates
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/S0377-8401(02)00029-9

Digestibility and nitrogen (N) utilisation in diets with low protein levels and supplemented with some amino acids were studied in two experiments with 21-week-old blue foxes ( Alopex lagopus). The dietary protein levels studied, expressed as percentage of metabolisable energy (ME) from protein, were in both experiments: 30, 22.5 and 15, corresponding on average 306, 244 and 174 g protein kg −1 dry matter (DM), respectively. At the two lowest levels the diets were fed as such or as supplemented with dl-methionine (experiment 1) or l-methionine or l-lysine (experiment 2). The added amount brought the level of the respective amino acid in the diet to that of diet containing 30% of ME from protein, and was verified by analyses. The apparent digestibility of crude protein ( p