Dry matter and nitrogen flows
The DM and N balances and the separation of faecal N in fractions for each of the experimental diets are shown in Table 6.
Values are expressed per kg of metabolic weight to correct the increase of pig weight throughout the two trial series. Neither
DM intake nor DM excretion both in faeces and urine were affected by dietary treatments. Protein source did not affect
N intake or the amount of N retained, as the high N excretion in the faeces from the SB compared to the SFM diet was
compensated by a lower N excretion in urine, with the WDDGS-based diet leading to intermediate values.
Diet type however greatly affected the excretory patterns of faecal N. Expressed as proportion of total N in faeces,
the SB diet had the highest proportion (0.171 vs 0.101 and 0.076) of undigested dietary nitrogen (UDN) and the lowest
(0.555 vs 0.616 and 0.630) of bacterial and endogenous debris nitrogen (BEDN) compared to the SFM and the WDDGS diets,
respectively. The proportion of water soluble nitrogen (WSN) on total faecal N was little affected by type of diet, averaging