University of Illinois, Urbana-Champaign, USA.
J Anim Sci. 2011 Jul;89(7):2139-44. doi: 10.2527/jas.2010-3522. Epub 2011 Feb 18.
A regional experiment was conducted to test the hypothesis that the concentration of dietary Ca does not affect the digestibility of Ca or P in diets fed to growing pigs. Six diets based on corn, potato protein isolate, cornstarch, and soybean oil were formulated. All diets also contained monosodium phosphate, crystalline AA, salt, and a vitamin-micromineral premix. The only difference among the diets was that varying concentrations of calcium carbonate were used to create diets containing 0.33, 0.46, 0.51, 0.67, 0.92, and 1.04% Ca. All diets contained between 0.40 and 0.43% P. Six universities participated in the experiment and each university contributed 2 replicates to the experiment for a total of 12 replicates (initial BW: 23.1 ± 4.4 kg). Pigs were placed in metabolism cages that allowed total, but separate, collection of feces and urine from the pigs. Pigs within each replicate were randomly allotted to the 6 diets and fed experimental diets for 14 d with urine and feces being collected over a 5-d period. Diets, feces, and urine samples were analyzed for Ca and P, and the daily balance, the apparent total tract digestibility (ATTD), and the retention of Ca and P were calculated. Results indicated that intake, fecal excretion, and urinary excretion of Ca increased (linear, P<0.05) as dietary Ca concentration increased. The daily intake of P was not affected by the dietary concentration of Ca, but fecal excretion of P increased (linear, P<0.05) as dietary Ca concentrations increased. In contrast, urinary P output was decreased (linear, P<0.05) as dietary Ca increased. The retention of Ca increased (linear, P<0.05) from 1.73 to 4.60 g/d, whereas the retention of P decreased (linear, P<0.05) from 1.98 to 1.77 g/d as dietary Ca concentrations increased. However, if calculated as a percentage of intake, both Ca and P retention were decreased (linear, P<0.05) as dietary Ca concentration increased (from 55.4 to 46.1% and from 48.4 to 43.5%, respectively). The ATTD of Ca was not affected by the dietary concentration of Ca, but the ATTD of P was decreased (linear, P<0.05) from 56.9 to 46.2% as dietary Ca concentration increased. It is concluded that the dietary concentration of Ca does not affect the ATTD of Ca in calcium carbonate, but increased concentrations of dietary Ca may decrease the ATTD of P in diets based on corn, potato protein isolate, and monosodium phosphate.
进行了一项区域性试验，以检验以下假设：日粮中钙的浓度不会影响生长猪饲粮中钙和磷的消化率。基于玉米、马铃薯蛋白分离物、玉米淀粉和大豆油配制了 6 种饲粮。所有饲粮均含有磷酸一氢钠、结晶型蛋氨酸、盐和维生素-矿物质预混料。这些饲粮唯一的区别是使用不同浓度的碳酸钙来配制含 0.33%、0.46%、0.51%、0.67%、0.92%和 1.04%钙的饲粮。所有饲粮的磷含量均在 0.40%至 0.43%之间。6 所大学参与了该试验，每所大学为该试验提供 2 个重复，共 12 个重复（初始 BW：23.1±4.4kg）。猪被安置在代谢笼中，这些代谢笼可以完全且分别收集猪的粪便和尿液。每个重复内的猪被随机分配到 6 种饲粮中，并连续 14d 饲喂试验饲粮，在此期间收集 5d 的尿液和粪便。对饲粮、粪便和尿液样品进行钙和磷分析，并计算钙和磷的日平衡、表观全肠道消化率（ATTD）和钙磷的存留率。结果表明，随着饲粮钙浓度的增加，钙的摄入量、粪便排泄量和尿排泄量呈线性增加（P<0.05）。饲粮钙浓度对磷的日摄入量没有影响，但随着饲粮钙浓度的增加，磷的粪便排泄量呈线性增加（P<0.05）。相反，随着饲粮钙浓度的增加，尿磷排泄量呈线性减少（P<0.05）。钙的存留量呈线性增加（P<0.05），从 1.73g/d 增加到 4.60g/d，而磷的存留量呈线性减少（P<0.05），从 1.98g/d 减少到 1.77g/d，随着饲粮钙浓度的增加。然而，如果以摄入量的百分比计算，则钙和磷的存留率均随饲粮钙浓度的增加而线性下降（P<0.05）（分别从 55.4%降至 46.1%和从 48.4%降至 43.5%）。钙的 ATTD 不受饲粮钙浓度的影响，但随着饲粮钙浓度的增加，磷的 ATTD 呈线性下降（P<0.05），从 56.9%降至 46.2%。因此，饲粮钙浓度不会影响碳酸钙中钙的 ATTD，但饲粮钙浓度的增加可能会降低基于玉米、马铃薯蛋白分离物和磷酸一氢钠的饲粮中磷的 ATTD。
