title: Nitrogen utilization in pigs fed diets with soybean and rapeseed products leading to different ileal endogenous nitrogen losses.
abstract: Nitrogen (N) balance was determined in 36 pigs (BW 24 to 30 kg) fed diets inducing different ileal endogenous N losses (ENL). We tested the hypothesis that enhanced ENL may be indicative of a higher recycling of endogenous proteins that will induce a greater urinary N loss and a lower efficiency of the dietary N utilization for retention. The cornstarch-based diets contained either soy concentrate (SC), soybean meal (SBM), a mixture of toasted and untoasted soybean meal (mSBM), dehulled-toasted rapeseed cake (RC1), non-dehulled-toasted rapeseed cake (RC2), or dehulled-untoasted rapeseed cake (RC3). The diets were balanced for their content of apparent ileal digestible (ID) CP (108 g/kg feed) and apparent ID of Lys, Thr, Met+Cys, Trp, and Ile. Feeding level was 2.7 times ME for maintenance per kilogram BWx75 and restricted to 88% of the requirements for ID Lys as the first-limiting amino acid. During a 5-d period, urine and feces were collected daily in metabolism cages. Compared with the SC diet (low ENL), the diets with SBM (medium ENL) and mSBM (high ENL) resulted in a greater (P < .05) urinary N excretion. Nitrogen retention tended to be less (P = .08) in pigs fed diets that caused greater ENL. The utilization of ID N for retention in pigs fed the mSBM diet was lower (P < .05) than for those fed the SC diet. There were no differences in urinary N excretion, N retention, and the utilization of ID N for retention in pigs fed the rapeseed diets of different fiber contents (hulls as the NDF source). We concluded that, at similar intakes of the first-limiting ID amino acid, N retention in pigs fed soybeans tended to be reduced by greater ENL as induced by antinutritional factors (e.g., trypsin inhibitors). Rapeseed hulls, as the predominant fiber source, do not affect N retention and the utilization of ID N for retention.
authors.affiliation: Wageningen Agricultural University, Wageningen Institute of Animal Sciences, Animal Nutrition Group, The Netherlands. witek.grala@alg.vv.wau.nl
authors.forename: W
authors.initials: W
authors.lastname: Grala
authors.forename: M W
authors.initials: MW
authors.lastname: Verstegen
authors.forename: A J
authors.initials: AJ
authors.lastname: Jansman
authors.forename: J
authors.initials: J
authors.lastname: Huisman
authors.forename: J
authors.initials: J
authors.lastname: Wasilewko
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001937:Brassica; D004032:Diet; D004063:Digestion / Q000502:physiology*; D005243:Feces; D007082:Ileum / Q000502:physiology*; D008239:Lysine / Q000378:metabolism; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009919:Orchiectomy; D013025:Glycine max; D013552:Swine / Q000502:physiology*
chemical_list: D000596:Amino Acids; D008239:Lysine; D009584:Nitrogen