Gaffield Katelyn N, Williams Hadley R, Becker Larissa L, DeRouchey Joel M, Woodworth Jason C, Tokach Mike D, Goodband Robert D, Gebhardt Jordan T, Faser Jill M
Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0201, USA.
Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-0201, USA.
Transl Anim Sci. 2023 Jul 31;7(1):txad090. doi: 10.1093/tas/txad090. eCollection 2023.
A total of 320 pigs (Line 241 × 600, DNA, Columbus, NE; initially 11.9 ± 0.22 kg) were used in a 21-d growth study to determine the available P () release curve for Smizyme TS G5 2,500 (Barentz, Woodbury, MN). At approximately 19 d of age, pigs were weaned, randomly allotted to pens, and fed common starter diets. Pigs were blocked by average pen body weight () and randomly allotted to one of eight dietary treatments on day 18 postweaning, considered day 0 of the study. Dietary treatments were derived from a single basal diet and ingredients including phytase, monocalcium P, limestone, and sand were added to create the treatment diets. Treatments included three diets containing increasing inorganic P from monocalcium P (0.11%, 0.20%, and 0.28% aP), or five diets with increasing phytase (500, 1,000, 1,500, 2,000, or 2,500 FTU/kg) added to the diet containing 0.11% aP. All diets were corn-soybean meal-canola meal-based and were formulated to contain 1.24% standardized ileal digestibility Lys, 0.30% phytate P, and an analyzed Ca:P ratio of 1.10:1. Prior to the beginning of the study, all pigs were fed a diet containing 0.11% aP for a 2-d period (days 16 to 18 postweaning). At the conclusion of the study, one pig, closest to the mean weight of each pen, was euthanized and the right fibula, rib, and metacarpal were collected to determine bone ash, density, and total bone P. Bones were weighed while suspended in a vessel of water and the weights used to calculate bone density (Archimedes' principle). For bone ash, bones were processed using the non-defatted method. For the overall experimental period, pigs fed increasing inorganic P had increased (quadratic, ≤ 0.033) average daily gain (), average daily feed intake (), and final BW and a tendency for increased (quadratic, ≤ 0.090) gain:feed ratio (). Pigs fed increasing phytase had increased (quadratic, ≤ 0.004) ADG, G:F, and final BW and increased (linear, = 0.019) ADFI. For fibula, rib, and metacarpal characteristics, pigs fed increasing aP from inorganic P had increased (linear, < 0.001) bone ash weight, percentage bone ash, bone density, and bone P concentration. Additionally, pigs fed increasing phytase had increased (linear or quadratic, < 0.05) bone ash weight, percentage bone ash, bone density, and bone P. TheaP release curve generated for Smizyme TS G5 2,500 for percentage bone ash using data generated from all three bones is aP = (0.228 × FTU/kg) ÷ (998.065 + FTU/kg).
总共320头猪（241品系×600品系，DNA，内布拉斯加州哥伦布市；初始体重11.9±0.22千克）用于一项为期21天的生长研究，以确定Smizyme TS G5 2500（明尼苏达州伍德伯里市巴伦茨公司）的有效磷（）释放曲线。大约在19日龄时，仔猪断奶，随机分配到栏中，并饲喂普通的起始日粮。仔猪按栏平均体重（）进行分组，并在断奶后第18天（即研究第0天）随机分配到八种日粮处理之一。日粮处理源自单一基础日粮，并添加了包括植酸酶、磷酸二氢钙、石灰石和沙子在内的成分以配制处理日粮。处理包括三种含有递增无机磷（来自磷酸二氢钙，有效磷分别为0.11%、0.20%和0.28%）的日粮，或五种在含有0.11%有效磷的日粮中添加递增植酸酶（500、1000、1500、2000或2500 FTU/kg）的日粮。所有日粮均以玉米-豆粕-油菜籽粕为基础，配制为含有1.24%的标准回肠可消化赖氨酸、0.30%的植酸磷，且分析得出的钙磷比为1.10:1。在研究开始前，所有仔猪在2天时间内（断奶后第16至18天）饲喂含有0.11%有效磷的日粮。在研究结束时，对每栏中最接近平均体重的一头猪实施安乐死，并采集右侧腓骨、肋骨和掌骨以测定骨灰、骨密度和总骨磷。将骨头悬挂在盛水容器中称重，并使用该重量计算骨密度（阿基米德原理）。对于骨灰，骨头采用非脱脂方法进行处理。在整个实验期内，饲喂递增无机磷的仔猪平均日增重（）、平均日采食量（）和末体重增加（二次曲线，≤0.033），且增重:采食量比（）有增加趋势（二次曲线，≤0.090）。饲喂递增植酸酶的仔猪平均日增重、增重:采食量比和末体重增加（二次曲线，≤0.004），且平均日采食量增加（线性，=0.019）。对于腓骨、肋骨和掌骨特性，饲喂递增无机磷有效磷的仔猪骨灰重量、骨灰百分比、骨密度和骨磷浓度增加（线性，<0.001）。此外，饲喂递增植酸酶的仔猪骨灰重量、骨灰百分比、骨密度和骨磷也增加（线性或二次曲线，<0.05）。使用来自所有三块骨头的数据生成的Smizyme TS G5 2500的骨灰百分比有效磷释放曲线为有效磷=（0.228×FTU/kg）÷（998.065+FTU/kg）。
