|ADELOA, OLAYIWOLA - Purdue University|
|AZAIN, MICHAEL - University Of Georgia|
|CARTER, SCOTT - Oklahoma State University|
|CRENSHAW, THOMAS - University Of Wisconsin|
|ESTIENNE, MICHAEL - Virginia Polytechnic Institution & State University|
|LINDEMANN, MERLIN - University Of Kentucky|
|MAXWELL, CHARLES - University Of Nebraska|
|MILLER, PHILLIP - University Of Nebraska|
|SHANNON, MARCHIA - University Of Missouri|
|VAN HEUGTEN, ERIC - North Carolina State University|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2015
Publication Date: 12/1/2015
Citation: Adeloa, O., Azain, M., Carter, S., Crenshaw, T., Estienne, M., Kerr, B.J., Lindemann, M., Maxwell, C., Miller, P., Shannon, M., van Heugten, E. 2015. A cooperative study on the standardized total-tract digestible phosphorus requirement of twenty-kilogram pigs. Journal of Animal Science. 93(12):5743-5753. doi: 10.2527/jas.2015-9509.
Interpretive Summary: Phosphorus is the second most abundant mineral element in the body following Ca. Routine empirical experiments provide estimates of requirements reflective of the changes over time in swine genetics, feedstuffs, and environment. In spite of the available literature evaluating phosphorus in growing pigs, there continues to be a need for more empirical studies on the standardized total-tract digestible phosphorus requirements of pigs to improve the modeling of phosphorus needs to optimize pig performance and minimize phosphorus excretion into the environment. Results in this study estimated that the standardized total-tract digestible phosphorus requirement in 20 to 40kg pigs ranged from 0.387% for average daily gain, 0.408% for feed efficiency, and an average of 0.430% for bone mineralization. Research results described in this report provides scientists and swine producers information on the standardized total-tract digestible phosphorus requirement of growing pigs in an effort to optimize pig performance and minimize potential phosphorus excretion.
Technical Abstract: Cooperative studies comprising growth performance, bone mineralization, and nutrient balance experiments were conducted at 11 stations to determine the standardized total-tract digestible (STTD) P requirement of 20-kg pigs using broken-line regression analysis. Monocalcium phosphate and limestone were added to a corn-soybean meal-based diet at the expense of cornstarch to establish 6 concentrations of STTD P from 1.54 to 5.15 g/kg in increments of 0.62 g/kg at a constant Ca:total P of 1.52:1.0. Diets were fed to 936 pigs (average initial BW of 19 kg) in 240 pens for 20 replicate pens of barrows and 20 replicate pens of gilts per diet. As STTD P increased from 1.54 to 5.15 g/kg of the diet for d 0 to 14, 14 to 28, and 0 to 28, the ADG, ADFI, and G:F increased (P < 0.01). Barrows gained and ate more (P < 0.05) than gilts during d 14 to 28 and d 0 to 28. There was no interaction between gender and STTD P concentration for any of the growth performance response criteria. There were both linear and quadratic increases (P < 0.05) in mineral density and content of the femur and for ash, Ca, and P expressed as a percentage of dry, fat-free metacarpal as dietary STTD P increased. Furthermore, maximum load of the femur and mineral density and content, and maximum load, as well as the Ca and P expressed as a percentage of metacarpal ash linearly increased (P < 0.01) with increasing dietary concentrations of STTD P. There were both linear and quadratic increases (P < 0.01) in apparent digestibility and retention of P with increasing concentrations of STTD P in the diets. Digestibility and retention of Ca linearly (P < 0.01) increased with increasing dietary concentrations of STTD P. Breakpoints determined from nonlinear broken-line regression analyses revealed estimates of 4.20 ± 0.102, 3.20 ± 0.036, or 3.87 ± 0.090 g/kg for ADG during d 0 to 14, 14 to 28, or 0 to 28, respectively. Corresponding estimates using G:F as the response criterion were 4.34 ± 0.146, 3.38 ± 0.139, or 4.08 ± 0.195 g/kg. When mineralization of the femur was used as criteria of response, estimates of STTD P requirement were 4.28, 4.28, or 4.34 for mineral density, mineral content, or maximum load, respectively. Using mineralization of metacarpal as criteria of response, estimates of STTD P requirement ranged from 3.5 to 5.0 g/kg depending on the metacarpal response criteria. The study provided empirical estimates of STTD P requirements of 20- to 40-kg pigs.