Stein H H, Kadzere C T, Kim S W, Miller P S
North Central Coordinating Committee on Swine Nutrition (NCCC-42) and Southern Regional Committee on Nutritional Systems for Swine to Increase Reproductive Efficiency (S-1012), South Dakota State University, USA.
J Anim Sci. 2008 Aug;86(8):1861-7. doi: 10.2527/jas.2008-0867. Epub 2008 Apr 25.
An experiment was conducted to test the hypothesis that the dietary inclusion rate of P does not influence the digestibility of P. The experiment was conducted at 4 experiment stations where the same protocol was followed. A total of 60 growing pigs (initial BW: 22.22 +/- 2.13 kg) were allotted to 6 dietary treatments with 10 replications per treatment. All pigs were placed in metabolism cages that allowed for the total, but separate, collection of urine and fecal materials. Six diets were formulated. The basal diet was based on corn (54.2%), soybean meal (20%), and cornstarch. No inorganic P was used, and the total concentration of P in the basal diet was calculated to be 0.29%. Five additional diets were formulated by adding monocalcium phosphate (MCP) in increments of 0.34% to the basal diet and thereby creating diets that were calculated to contain 0.36, 0.43, 0.50, 0.57, and 0.64% total P, respectively. Ground limestone was also added to these diets to maintain a calculated Ca:P ratio of 1.2:1. The balances of Ca and P and the apparent total tract digestibility (ATTD) of Ca and P were calculated for each diet. The contribution of P from the basal diet was then subtracted from the MCP-containing diets to calculate the balance and ATTD for P in MCP. Results of the experiment showed that the absorption and retention of both Ca and P increased (linear, P < 0.001) with increasing concentrations of Ca and P in the diet. The ATTD for Ca ranged from 62.3 to 66.8% and was not influenced by the dietary concentration of Ca. However, the ATTD for P increased from 38.4 to 65.2% as increasing levels of MCP were added to the diet (linear, P < 0.001). Increasing P intake from MCP increased (linear, P < 0.001) the excretion of P in the feces, but the quantity of P that was absorbed and retained also increased (linear, P < 0.001) as more P from MCP was added to the diet. When measured as a percentage of P intake, P retention was not influenced by the dietary P concentration. The ATTD for P in MCP ranged from 79.5 to 88.5% and was not affected by the concentration of P in the diet. Results of this experiment demonstrated that the digestibility and absorption of P from MCP are not influenced by the dietary concentration of P.
进行了一项实验以检验磷的日粮添加率不影响磷消化率这一假设。该实验在4个实验站进行，所有站点均遵循相同的方案。总共60头生长猪（初始体重：22.22±2.13千克）被分配到6种日粮处理组，每组处理10个重复。所有猪均被安置在代谢笼中，以便分别收集尿液和粪便。配制了6种日粮。基础日粮以玉米（54.2%）、豆粕（20%）和玉米淀粉为基础。未使用无机磷，基础日粮中磷的总浓度经计算为0.29%。通过向基础日粮中以0.34%的增量添加磷酸二氢钙（MCP）来配制另外5种日粮，从而配制出经计算分别含有0.36%、0.43%、0.50%、0.57%和0.64%总磷的日粮。还向这些日粮中添加了石灰石粉，以使钙磷比维持在1.2:1。计算每种日粮的钙磷平衡以及钙和磷的表观全肠道消化率（ATTD）。然后从含MCP的日粮中减去基础日粮中磷的贡献量，以计算MCP中磷的平衡和ATTD。实验结果表明，随着日粮中钙和磷浓度的增加，钙和磷的吸收与保留量均增加（呈线性关系，P<0.001）。钙的ATTD范围为62.3%至66.8%，不受日粮钙浓度的影响。然而，随着日粮中MCP添加量的增加，磷的ATTD从38.4%增加至65.2%（呈线性关系，P<0.001）。从MCP中增加磷摄入量会增加（呈线性关系，P<0.001）粪便中磷的排泄量，但随着日粮中添加更多来自MCP的磷，吸收和保留的磷量也会增加（呈线性关系，P<0.001）。以磷摄入量的百分比衡量时磷的保留量不受日粮磷浓度的影响。MCP中磷的ATTD范围为79.5%至88.5%，不受日粮中磷浓度的影响。本实验结果表明，日粮中磷的浓度不影响MCP中磷的消化率和吸收。
