Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS.
Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS.
J Anim Sci. 2019 Oct 3;97(10):4023-4031. doi: 10.1093/jas/skz256.
A study was conducted to determine the standardized total tract digestible phosphorus (STTD P) requirement for 24- to 130-kg finishing pigs housed under commercial conditions. A total of 1,130 barrows and gilts (PIC 359 × 1050, Hendersonville, TN; initially 24.2 kg) were used, with 26 to 27 pigs per pen with 7 replicates per treatment. Pens of pigs were allotted to treatments in a randomized complete block design with body weight (BW) as the blocking factor. The dietary treatments were fed in 4 phases and were formulated to contain 80%, 90%, 100%, 115%, 130%, and 150% of the National Research Council (NRC) requirement estimate for finishing pigs within each phase. Weight ranges for each phase were: 27 to 49, 49 to 76, 76 to 90, and 90 to 130 kg. Treatments were achieved by increasing the amount of monocalcium phosphate at the expense of corn in the diet with no added phytase. All diets were formulated to contain a similar 1.14:1 to 1.16:1 total Ca:P ratio across treatments in all phases. Increasing STTD P resulted in a quadratic response (P < 0.05) in average daily gain (ADG), gain-to-feed ratio (G:F), and final BW. The greatest improvement was observed with STTD P at 130% of NRC for ADG and final BW and at 115% STTD P for G:F. Average daily feed intake increased linearly (linear, P < 0.05) with the inclusion of STTD P. Increasing STTD P resulted in an increase (quadratic, P < 0.05) in hot carcass weight (HCW) and carcass ADG with the greatest response observed with STTD P at 130% of NRC. There was a marginally significant response (quadratic, P < 0.10) in carcass G:F, with the greatest improvement with STTD P at 115% of NRC. Carcass yield decreased (linear, P < 0.05) with increasing STTD P, while there was a marginally significant (linear, P < 0.10) decrease in backfat and increase in fat-free lean. At the end of the study, a metacarpal was collected and analyzed for bone ash. Increasing STTD P resulted in an increase (linear, P < 0.05) in bone ash weight and percentage ash. For ADG and G:F, the quadratic model demonstrated the best fit. The maximum response in ADG and G:F was estimated at 122% and 116% of NRC STTD P, respectively. The broken-line linear model best fit the data for percentage bone ash, with a plateau achieved at 131% of the NRC STTD P. In conclusion, the estimated STTD P requirement of 24 to 130 kg ranged from 116% to 131% of the NRC publication (2012) requirement estimate.
一项研究旨在确定在商业条件下饲养的 24-130 公斤育肥猪的标准化总肠道可消化磷（STTD P）的需求。共有 1130 头阉公猪和母猪（PIC 359 × 1050，亨德森维尔，田纳西州；初始体重 24.2 公斤）被用于试验，每个栏舍有 26-27 头猪，每个处理有 7 个重复。猪栏根据体重（BW）作为分组因素，按随机完全区组设计分配到处理中。日粮处理分为 4 个阶段，每个阶段的配方均含有 80%、90%、100%、115%、130%和 150%的 NRC 育肥猪估计需求。每个阶段的体重范围分别为：27-49 公斤、49-76 公斤、76-90 公斤和 90-130 公斤。通过增加日粮中磷酸一钙的用量，同时减少玉米的用量来实现处理效果，而不添加植酸酶。所有日粮的配方均含有相似的 1.14:1 至 1.16:1 的总钙：磷比，各处理均相同。STTD P 增加导致平均日增重（ADG）、增重与采食量比（G:F）和最终 BW 呈二次反应（P<0.05）。在 ADG 和最终 BW 方面，STTD P 达到 NRC 的 130%时，以及在 G:F 方面达到 STTD P 115%时，观察到最大的改善。平均日采食量随 STTD P 的增加呈线性增加（线性，P<0.05）。STTD P 增加导致热胴体重（HCW）和胴体 ADG 增加（二次，P<0.05），在 STTD P 达到 NRC 的 130%时观察到最大的反应。胴体 G:F 呈边际显著（二次，P<0.10）增加，在 STTD P 达到 NRC 的 115%时改善最大。胴体产肉率随 STTD P 的增加而下降（线性，P<0.05），而背脂减少，无脂瘦肉增加。在研究结束时，收集并分析了掌骨进行灰分分析。STTD P 的增加导致灰分重量和灰分百分比增加（线性，P<0.05）。对于 ADG 和 G:F，二次模型表现出最佳拟合。ADG 和 G:F 的最大反应估计分别为 NRC STTD P 的 122%和 116%。折线线性模型最适合骨灰分数据，在 NRC STTD P 的 131%时达到平台。总之，24-130 公斤育肥猪的 STTD P 估计需求在 NRC 出版物（2012 年）需求估计的 116%-131%之间。
