title: Novel procedure for estimating endogenous losses and measurement of apparent and true digestibility of phosphorus by growing pigs.
abstract: An experiment was conducted to evaluate a novel procedure for estimating endogenous losses of P and for measuring the apparent total tract digestibility (ATTD) and true total tract digestibility (TTTD) of P in 5 inorganic P sources fed to growing pigs. The P sources were dicalcium phosphate (DCP), monocalcium phosphate (MCP) with 50% purity (MCP50), MCP with 70% purity (MCP70), MCP with 100% purity (MCP100), and monosodium phosphate (MSP). A gelatin-based, P-free basal diet was formulated and used to estimate endogenous losses of P. Five P-containing diets were formulated by adding 0.20% total P from each of the inorganic P sources to the basal diet. A seventh diet was formulated by adding 0.16% P from MCP70 to the basal diet. All diets were fed to 7 growing pigs in a 7 x 7 Latin square design, and urine and feces were collected during 5 d of each period. The endogenous loss of P was estimated as 139 +/- 18 mg/kg of DMI. The ATTD of P in MSP was greater (P < 0.05) than in DCP, MCP50, and MCP70 (91.9 vs. 81.5, 82.6, and 81.7%, respectively). In MSP, the TTTD of P was 98.2%. This value was greater (P < 0.05) than the TTTD of P in DCP, MCP50, and MCP70 (88.4, 89.5, and 88.6%, respectively). The ATTD and the TTTD for MCP70 were similar in diets formulated to contain 0.16 and 0.20% total P. Results from the current experiment demonstrate that a P-free diet may be used to measure endogenous losses of P in pigs. By adding inorganic P sources to this diet, the ATTD of P can be directly measured and the TTTD of P may be calculated for each source of P.
authors.affiliation: Department of Animal and Range Sciences, South Dakota State University, Brookings 57007, USA.
authors.forename: G I
authors.initials: GI
authors.lastname: Petersen
authors.forename: H H
authors.initials: HH
authors.lastname: Stein
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000502:physiology*; D008297:Male; D010758:Phosphorus / Q000737:chemistry / Q000502:physiology*; D016226:Phosphorus, Dietary / Q000032:analysis / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*
chemical_list: D016226:Phosphorus, Dietary; D010758:Phosphorus