title: Inevitable losses of phosphorus in pigs, estimated from balance data using diets deficient in phosphorus.
abstract: Faecal losses of phosphorus (P) were determined in 66 growing pigs weighing between 30 and 70 kg on a semi-purified diet containing less than 1.3 g P/kg DM. Regression analysis showed that the coefficient of absorption of P from this diet was 82.5% and that inevitable faecal P excretion of pigs fed this diet was, on average, 5.9 mg/kg BW.d-1 with no statistically significant effect of body weight on faecal P excretion within the range of body weight studied. Semi-purified diets almost identical in composition were also fed to 5 piglets weighing about 20 kg and to 4 heavy pigs of about 150 kg BW. Inevitable daily faecal losses of P were calculated to be 6.2 mg/kg BW in piglets and 6.8 mg/kg BW in the heavy pigs. It is concluded that inevitable faecal losses of P do depend on body weight and that the variation faecal P excretion was too great to allow detecting this effect within the limited range between 30 and 70 kg BW. Further diets were obtained by blending various ingredients into the semi-purified diet. From a total of 262 balances measured under the condition of suboptimal P supply it is concluded that daily inevitable urinary losses of P depend on body weight and, on average, amount to 0.35 mg/kg BW. It is concluded that under the conditions of suboptimal P supply the utilisation of digestible P is almost complete.
authors.affiliation: Department of Animal Nutrition, University of Bonn, Germany. mrod@audi.itz.uni-bonn.de
authors.forename: M
authors.initials: M
authors.lastname: Rodehutscord
authors.forename: R
authors.initials: R
authors.lastname: Haverkamp
authors.forename: E
authors.initials: E
authors.lastname: Pfeffer
mesh_terms: D000821:Animal Feed; D000818:Animals; D004063:Digestion / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D008297:Male; D009919:Orchiectomy; D010758:Phosphorus / Q000032:analysis / Q000172:deficiency* / Q000378:metabolism*; D012044:Regression Analysis; D013552:Swine
chemical_list: D010758:Phosphorus