Free Access
Reprod. Nutr. Dev.
Volume 42, Number 6, November-December 2002
Page(s) 537 - 544
Reprod. Nutr. Dev. 42 (2002) 537-544
DOI: 10.1051/rnd:2002039

Rumen escape of methionine and lysine administered intraruminally to growing double-muscled Belgian Blue bulls

Eric Froidmont, Pierre Rondia, André Théwis and Yves Beckers

Faculté Universitaire des Sciences Agronomiques, passage des Déportés 2, 5030 Gembloux, Belgium
(Received 16 April 2002; accepted 15 July 2002)

In many dietary conditions, methionine (Met) and lysine (Lys) are the most limiting amino acids (AA) for ruminants. The AA protected from ruminal fermentation are not commercially available, with the exception of Met which is not always economical, especially for meat production. This study measured ruminal escape of free Met and Lys supplemented intraruminally to fast growing bulls. Six double-muscled Belgian Blue bulls, fed a high concentrate diet and fitted with a rumen cannula, received free Met (40 $\mathrm{g}\cdot\mathrm{d}^{-1}$) and free Lys (60 $\mathrm{g}\cdot\mathrm{d}^{-1}$), individually or simultaneously, in a duplicated Latin square design. The mean ruminal escape of Met and Lys reached 37 and 45% respectively, and did not differ if administered separately or together. Plasma Lys and Met concentrations were increased by 504 and 126%, respectively. Substantial proportions of free AA escaped ruminal fermentation and were available for absorption from the small intestine when they were administered at physiologically high levels.

Key words: ruminant / methionine / lysine / rumen escape / plasma

Correspondence and reprints: Eric Froidmont

© INRA, EDP Sciences 2002