Ketaren P P, Batterham E S, Dettmann E B, Farrell D J
NSW Agriculture, Wollongbar Agricultural Institute, Australia.
Br J Nutr. 1993 Jul;70(1):269-88. doi: 10.1079/bjn19930122.
Experiments were conducted with pigs and rats to determine the availability of P in feeds. Initially, the availability of P in a soya-bean meal and field peas (Pisum sativum cultivar Early Dun) was assessed using a slope-ratio assay for grower pigs. Three different levels of either monosodium phosphate (MSP), soya-bean meal or field peas were added to a basal sucrose-soya-bean meal diet (2.5 g/kg P) to give three levels of P (3.0, 3.5 and 4 g/kg) for each source. The diets were offered for 35 d at three times maintenance energy requirements to female pigs initially weighing 20 kg live weight. Several bone variables and the ash and P concentration and retention levels in the empty body were used as criteria of availability. The responses to MSP were linear for all variables. However, responses to P in the test proteins, particularly soya-bean meal, were mostly non-linear, except for ash and P concentrations and retentions in the empty body. The estimates of P availability in the soya-bean meal and in the field peas were dependent on the criteria used to assess availability. Using bone variables as the criterion, the availabilities of P in soya-bean meal and field peas were approximately 0.17 and 0.38 respectively. Using ash or P concentrations or retentions in the empty body as the response criterion, the availabilities of P in soya-bean meal and field peas were 0.61 and 0.38 respectively. The mean retention values for P from MSP, soya-bean meal and field peas were 0.74, 0.33 and 0.21 respectively. Experiments were then conducted to define the conditions necessary for a slope-ratio assay for P availability with growing rats to determine if they could be used as a model to assess P availability for pigs. These experiments examined level of P in the diet, the effect of Ca:P ratio and criteria for assessing response (growth rate, feed intake, feed conversion ratio, bone ash and bone bending moment). The results indicated that a suitable range of dietary P for a slope-ratio assay in rats was 1.8-3.5 g/kg, with Ca:P ratio of between 1.3 and 6.2, and that ash content or bone bending moment of the femur bone were suitable criteria of response. However, using bone bending moment as the criterion of response, the availability of P in soya-bean meal was 0.81, which was considerably higher than the estimate with pigs.(ABSTRACT TRUNCATED AT 400 WORDS)
以猪和大鼠进行实验来测定饲料中磷的可利用率。最初，采用斜率比分析法对生长猪评估豆粕和豌豆（豌豆品种Early Dun）中磷的可利用率。向基础蔗糖 - 豆粕日粮（2.5 g/kg磷）中添加三种不同水平的磷酸二氢钠（MSP）、豆粕或豌豆，以使每种来源的磷达到三个水平（3.0、3.5和4 g/kg）。以维持能量需求的三倍向初始体重20 kg的母猪提供这些日粮35天。将几个骨骼变量以及空体中的灰分、磷浓度和保留水平用作可利用率的标准。所有变量对MSP的反应呈线性。然而，除了空体中的灰分、磷浓度和保留量外，试验蛋白质中磷的反应大多是非线性的，特别是豆粕。豆粕和豌豆中磷可利用率的估计值取决于用于评估可利用率的标准。以骨骼变量为标准，豆粕和豌豆中磷的可利用率分别约为0.17和0.38。以空体中的灰分或磷浓度或保留量作为反应标准，豆粕和豌豆中磷的可利用率分别为0.61和0.38。来自MSP、豆粕和豌豆的磷的平均保留值分别为0.74、0.33和0.21。随后进行实验以确定用生长大鼠进行磷可利用率斜率比分析所需的条件，以确定它们是否可作为评估猪磷可利用率的模型。这些实验研究了日粮中磷的水平、钙磷比的影响以及评估反应的标准（生长速率、采食量、饲料转化率、骨灰和骨弯曲力矩）。结果表明，大鼠斜率比分析中合适的日粮磷范围为1.8 - 3.5 g/kg，钙磷比在1.3至6.2之间，并表明股骨的灰分含量或骨弯曲力矩是合适的反应标准。然而，以骨弯曲力矩作为反应标准时，豆粕中磷的可利用率为0.81，这比用猪得出的估计值高得多。（摘要截短至400字）
