Effect of Barley Fibres and Barley Intake on the Ileal Endogenous Nitrogen Losses in Piglets

Ileal endogenous N losses (ENL) were measured, using the¹⁵N isotope dilution technique, in piglets (17 kg) fed different barley genotypes (naked, spring, winter with low/high beta -glucan content) or diets containing 330, 530, 730 or 930 g of a blend of barleys/kg diet. The apparent protein and amino acid digestibilities of the naked variety and the winter variety with a high beta -glucan content were, on average, significantly higher than those for the other two varieties. The ENL were inversely correlated (p<0·01) with the apparent digestibilities but the difference between each of them was not significant (p>0·05). The ENL increased linearly with the inclusion level of barley in a N-free basal diet (2 mg endogenous N/g barley). Isolated hulls added to a N-free diet at the rate of 100 or 200 g/kg diet exerted no significant effect on the ENL (1·80 g endogenous N/kg diet in both cases vs. 1·76 g for the basal level). On the contrary, the effect of isolated bran, measured under similar conditions, was significantly higher and dependent on fibre intake (2·59 and 3·31 g N/kg diet, respectively). It is concluded that the ENL are affected by the insoluble bran fibre but not by the hulls, nor by the level of beta -glucan.