Zhai Hengxiao, Bergstrom Jon, Zhang Jingcheng, Dong Wei, Wang Zhenzhen, Stamatopoulos Kostas, Cowieson Aaron J
DSM (China) Animal Nutrition Research Center, Bazhou 065799, China.
DSM Nutritional Products, Parsippany, NJ 07054, USA.
Transl Anim Sci. 2023 Jan 9;7(1):txad006. doi: 10.1093/tas/txad006. eCollection 2023 Jan.
The objective of this study was to investigate the effects of increasing dietary total Ca/total P ratios on growth performance, digestibility of Ca and P, bone mineralization, and concentrations of Ca and P in urine and plasma in nursery pigs. There were six diets in a randomized complete block design, including one positive control and five diets corresponding to five total Ca/total P ratios: 0.55, 0.73, 0.90, 1.07, and 1.24 (analyzed as 0.58, 0.75, 0.93, 1.11, and 1.30). These five diets were deficient in P but supplemented with 1,000 phytase units/kg feed. Each diet was fed to six pens of eight pigs (four barrows and four gilts per pen). All diets contained 3 g/kg TiO, and fecal samples were collected from each pen on days 5-7 of trial. At the end, one pig per pen was sacrificed to collect the right tibia and urine in the bladder. The results showed that increasing dietary Ca/P ratio to 0.93 increased gain:feed but then gain:feed decreased as the Ca/P ratio was increased to 1.30 (linear and quadratic, < 0.05). Although average daily gain and final BW were unaffected by changing Ca/P ratio in diet, dry bone weight; weights of bone ash, Ca and P; and bone Ca/P ratio increased linearly ( < 0.001) with increasing dietary Ca/P ratio. The percent bone Ca showed a tendency to increase ( = 0.064). Increasing dietary Ca/P ratio decreased apparent total tract digestibility (ATTD) of Ca and P linearly ( < 0.05) and the concentration of digestible P linearly ( < 0.001), but increased the concentration of digestible Ca (linear and quadratic effects: < 0.01) and the digestible Ca/P ratio (linear effect: < 0.001). In plasma, the concentration of Ca increased both linearly ( < 0.01) and quadratically ( = 0.051), whereas the concentration of P tended (linear and quadratic, < 0.10) to decrease with increasing dietary Ca/P ratio. Similarly, in urine, the concentration of Ca increased both linearly and quadratically ( < 0.05), whereas the concentration of P decreased linearly ( < 0.01). In conclusion, increasing the dietary Ca/P ratio reduced feed efficiency but increased bone mass and the amounts of Ca and P deposited in bone of nursery pigs fed diets supplemented with 1,000 FYT/kg phytase. The increases in bone growth led to a reduction of urinary P excretion that exceeded the decreased digestible P supplied in diet with the widening dietary Ca/P ratios.
本研究的目的是调查提高日粮总钙/总磷比例对保育猪生长性能、钙和磷的消化率、骨矿化以及尿液和血浆中钙和磷浓度的影响。采用随机完全区组设计，有六种日粮，包括一个阳性对照和五种对应于五个总钙/总磷比例的日粮：0.55、0.73、0.90、1.07和1.24（分析值为0.58、0.75、0.93、1.11和1.30）。这五种日粮磷含量不足，但每千克饲料添加1000单位植酸酶。每种日粮饲喂六栏猪，每栏八头（每栏四头公猪和四头母猪）。所有日粮均含有3 g/kg二氧化钛，在试验第5至7天从每栏采集粪便样本。试验结束时，每栏处死一头猪以收集右胫骨和膀胱中的尿液。结果表明，将日粮钙/磷比例提高到0.93时，增重/采食量增加，但当钙/磷比例提高到1.30时，增重/采食量下降（线性和二次曲线，P<0.05）。尽管日粮中钙/磷比例的变化对平均日增重和末重没有影响，但干骨重、骨灰重、钙和磷的重量以及骨钙/磷比例随着日粮钙/磷比例的增加呈线性增加（P<0.001）。骨钙百分比呈增加趋势（P = 0.064）。提高日粮钙/磷比例使钙和磷的表观全肠道消化率（ATTD）呈线性下降（P<0.05），可消化磷浓度呈线性下降（P<0.001），但可消化钙浓度增加（线性和二次曲线效应：P<0.01）以及可消化钙/磷比例增加（线性效应：P<0.001）。在血浆中，钙浓度呈线性增加（P<0.01）和二次曲线增加（P = 0.051），而磷浓度随着日粮钙/磷比例的增加呈下降趋势（线性和二次曲线，P<0.10）。同样，在尿液中，钙浓度呈线性和二次曲线增加（P<0.05），而磷浓度呈线性下降（P<0.01）。总之，提高日粮钙/磷比例降低了饲料效率，但增加了饲喂每千克饲料添加1000单位菲汀酶日粮的保育猪的骨量以及骨中钙和磷的沉积量。随着日粮钙/磷比例的扩大，骨生长的增加导致尿磷排泄减少，超过了日粮中可消化磷供应的减少量。
