INVESTIGATIONS ABOUT THE INFLUENCE OF A D IFFERENT PROTEIN AND FIBER INTAKE ON THE ENDOGENOUS PROTEIN FLUX AT THE ILEUM OF N-15-LABELED PIGS

The endogenous N in ileal digesta of pigs was estimated in two experim ental variants. In variant 1 the crude protein content of a wheat-maiz e-fish meal diet was 18% and the crude fibre content was 1.9% (diet 1) and 2.7% resp. (diet 2). In variant 2 the crude protein content was 1 2.5% (wheat-maize-diet) and the crude fibre content was 4.1% (diet 3) and 5.5% resp. (diet 4). The higher crude fibre content of the diets 2 -4 was provided by means of a supplementation with partially hydrolyze d straw meal plus pectin (2:1w/w). Four miniature pigs with an average initial body weight of 29 kg, were fitted with a ileocaecal re-entran t cannula and received each one of the four different diets. (NH4Cl)-N -15, added to the diets, was given for 5 days (150 mg N-15-excess/kg(0 .75) BWd) to labell the animals with N-15. Ileal digesta, urine and f aeces were collected over 24 hours on 8th, 10th and 12th day after the first intake of N-15. The N-15-excess of urine N was used as the comp arative measure of N-15-excess of endogenous protein. The amount of ni trogen collected in ileal digesta was in order of the diets 1-4 = 258, 299, 200 and 224 mg/kg(0.75) BWd and of these amounts were 50.1, 52. 1, 56.1 and 50.4% of endogenous origin. This were corresponding, after conversion into crude protein to 9.1, 11.2, 10.8 and 11.0 g/100 g cru de protein intake or 16.9, 19.7, 13,8 and 13.4 g/kg dry matter intake, respectively. The bacterial N-flow were in order the diets 1-4 = 94.0 ; 72.7; 55.8 and 52.6 mg/kg(0.75) BWd and 73, 46, 50 and 47% resp. of the endogenous N or 36, 24, 28 and 24% of the ileal total N. The resu lts show, that the absolute amounts of endogenous and bacterial N at t he terminal ileum were significantly increased by a higher crude prote in content of the diet. The percentage of endogenous and bacterial N o n the total N of the ileal digesta was not affected neither by the cru de protein content of the diets nor by the fibre supplements.