Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
J Anim Sci. 2010 Dec;88(12):3964-76. doi: 10.2527/jas.2010-3011. Epub 2010 Aug 20.
The application of phytase in conventional dry swine diets has been shown to improve P availability and utilization. The effectiveness of phytase may be further improved by steeping feedstuffs with phytase before feeding. A study was conducted to determine the value of steeping high-moisture corn (HMC) with phytase in P-deficient liquid diets for starter pigs. A total of 384 pigs were weaned at 19 to 23 d of age and 6.7 ± 0.1 kg of BW. Pigs were randomly assigned to pens, with 8 barrows and 8 gilts per pen and 5 pens per dietary treatment (only 4 pens for the control treatment). The 5 dietary treatments (all HMC-based 3-phase feeding programs) were 1) negative control with no added phytase, 2 and 3) negative control with phytase added to the HMC to achieve 62.5 or 125 phytase units (FTU)/kg of HMC (DM basis) of phytase added to the HMC and allowed to steep for 24 h before feeding, and 4 and 5) negative control with the same amount of phytase added to the base mix without steeping before feeding. Total P content (88% DM basis) averaged 0.49% in phase I and 0.37% in phase II and III diets. Individual pig BW and per pen ADFI were measured on a weekly basis. Apparent total tract digestibility of DM, OM, CP, P, and Ca were measured using titanium dioxide as an indigestible marker in phase III diets. At the end of the study (7 wk postweaning), 4 pigs from each pen were killed for assessment of body composition, breaking strength and mineral content of metacarpals, total and soluble P content in duodenal digesta, and urinary P content. There was no effect of added phytase on ADG, ADFI, or G:F. The soluble P:total P ratio in duodenal digesta was increased with the addition of phytase (P < 0.05). Steeping HMC with phytase resulted in greater digestibility of DM and CP (P < 0.01). A trend toward increased digestibility of Ca with added phytase was observed (P = 0.07), but there was no effect of dietary treatment on P digestibility. Urinary P content was considerably greater in pigs fed diets with exogenous phytase (P < 0.05). Additional phytase resulted in increased P and Ca content in the empty body (P < 0.05). Metacarpal content of P (P < 0.05) and Ca (P = 0.07) and breaking strength (P < 0.05) were improved with added phytase. Despite a lack of effect on P digestibility, added phytase improved retention of Ca and P in starter pigs fed P-deficient HMC-based liquid diets. There was little benefit from steeping HMC with phytase before feeding.
植酸酶在常规干猪饲料中的应用已被证明可以提高磷的利用率。在喂养前用植酸酶浸泡饲料可以进一步提高植酸酶的效果。进行了一项研究，以确定在磷缺乏的液体饲料中用植酸酶浸泡高水分玉米（HMC）对仔猪的价值。共有 384 头仔猪在 19-23 日龄断奶，体重为 6.7±0.1kg。仔猪随机分配到猪舍，每个猪舍 8 头公猪和 8 头母猪，每个饲料处理 5 个猪舍（仅控制处理 4 个猪舍）。5 种饲料处理（均基于 HMC 的 3 阶段饲养计划）为：1）无添加植酸酶的负对照，2 和 3）在 HMC 中添加植酸酶以达到 62.5 或 125 植酸酶单位（FTU）/kg HMC（DM 基础）的负对照，并在喂养前浸泡 24 小时，和 4 和 5）在喂养前没有浸泡的基础混合物中添加相同量的植酸酶的负对照。I 期和 III 期饲料中总磷含量（以 88%DM 为基础）平均为 0.49%和 0.37%。每周测量每头猪的 BW 和每头猪的 ADFI。在 III 期饲料中使用二氧化钛作为不消化标记物测量 DM、OM、CP、P 和 Ca 的全肠道消化率。在研究结束时（断奶后 7 周），每个猪舍从每头猪中取出 4 头进行评估，以评估身体成分、掌骨的断裂强度和矿物质含量、十二指肠食糜中的总磷和可溶性磷含量以及尿磷含量。添加植酸酶对 ADG、ADFI 或 G:F 没有影响。十二指肠食糜中可溶性磷与总磷的比值随着植酸酶的添加而增加（P<0.05）。用植酸酶浸泡 HMC 可提高 DM 和 CP 的消化率（P<0.01）。观察到添加植酸酶可提高 Ca 的消化率呈上升趋势（P=0.07），但饲料处理对 P 消化率没有影响。饲喂添加外源植酸酶的日粮的猪尿磷含量明显更高（P<0.05）。添加植酸酶可增加空体的 P 和 Ca 含量（P<0.05）。添加植酸酶可提高掌骨的 P（P<0.05）和 Ca（P=0.07）含量以及断裂强度（P<0.05）。尽管对 P 消化率没有影响，但在磷缺乏的基于 HMC 的液体饲料中添加植酸酶可提高仔猪对 Ca 和 P 的保留。在喂养前用植酸酶浸泡 HMC 几乎没有好处。
