1. G. M. Barnett , 1994 :Bioresource Technol.49 ,139, 147 .
2. G. M. Barnett , 1994 :Bioresource Technol.49 ,149, 155 .
3. J. Bartelt, W. Drochner, A. Sommer, J. P. Laplace, C. Fevrier, and A. Barbeau , 1997 :Recovery of different nitrogen fractions at the distal ileum in15N-labelled pigs fed grain diets with or without fish meal and graded levels of fibre . In:Proc. 7th Int. Symp. on Digestive Physiology in Pigs,EAAP Publication88 ,Saint-Malo.617, 620 .
4. K. Bitar, and J. G. Reinhold , 1972 :Biochim. Biophys. Acta268 ,442, 452 .
5. J. A. M. Bruce, and F. Sundstl , 1995 :Can. J. Anim. Sci.75 ,121, 127 .