Department of Animal Science, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.
J Anim Sci. 2013 Jan;91(1):298-308. doi: 10.2527/jas.2012-5211. Epub 2012 Oct 16.
Three experiments were conducted to evaluate energy, AA, and P digestibility in a phytase transgenic corn (PTC) containing a phytase gene (phyA2) isolated from Aspergillus niger compared with a nontransgenic near-isoline conventional corn (CC) grown in the same environmental conditions for growing pigs. Experiment 1 was an energy balance experiment conducted to measure DE and ME in PTC and CC. Eighteen growing barrows (initial BW 25.8±0.3 kg) from 9 litters were allotted by BW and litter to 1 of 2 dietary treatments with 9 pigs per treatment in a randomized complete block design. Pigs were individually placed in metabolism cages and fed diets based on the 2 corns. The DE and ME in PTC (3,967 and 3,941 kcal/kg of DM, respectively) were greater (P<0.05) than those in CC (3,917 and 3,848 kcal/kg of DM, respectively). Experiment 2 was conducted to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of CP and AA in the 2 corns. Eighteen growing barrows (initial BW 41.8±0.7 kg) were equipped with a T-cannula in the distal ileum. Pigs were placed in metabolism cages in a completely randomized design with 3 dietary treatments of 6 pigs each. An N-free diet was used to estimate basal endogenous losses of CP and AA. The AID and SID values for CP and all AA did not differ between the 2 corns. Experiment 3 was conducted to measure apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) values of P in the 2 corns. Eighteen growing pigs (initial BW 30.5±0.5 kg) from 6 litters were placed in metabolism cages in a randomized complete block design with 3 dietary treatments of 6 pigs each based on BW and litter. Two diets were based on the 2 corns, and a P-free diet was used to measure endogenous P losses. The ATTD and STTD values of P were greater (P<0.05) in the PTC diet (71.4% and 76.9%, respectively) than those in the CC diet (27.6% and 33.4%, respectively). Pigs fed the PTC diet had a greater (P<0.05) P retention (70.7%) than those fed the CC diet (27.1%). It was concluded that PTC had a greater digestibility of energy and P than CC for growing pigs. As a consequence, if PTC replaces CC in a pig diet, the DE and ME in the diet will increase, and less inorganic P will need to be supplemented to the diet, and thus P excretion in manure will be decreased.
进行了三项实验，以评估与在相同环境条件下生长的非转基因近交系常规玉米（CC）相比，含有从黑曲霉（Aspergillus niger）中分离的植酸酶基因（phyA2）的植酸酶转基因玉米（PTC）的能量、AA 和磷消化率。实验 1 是一项能量平衡实验，用于测量 PTC 和 CC 的 DE 和 ME。18 头生长育肥猪（初始 BW 25.8±0.3 kg）来自 9 窝，按 BW 和窝分配到 2 种饲粮处理中的 1 种，每个处理 9 头猪，采用随机完全区组设计。猪单独放在代谢笼中，根据 2 种玉米进行饲喂。PTC（分别为 3,967 和 3,941 kcal/kg DM）的 DE 和 ME 高于 CC（分别为 3,917 和 3,848 kcal/kg DM）（P<0.05）。实验 2 用于测量 2 种玉米中 CP 和 AA 的表观回肠消化率（AID）和标准回肠消化率（SID）值。18 头生长育肥猪（初始 BW 41.8±0.7 kg）在回肠远端装有 T 型管。猪采用完全随机设计，在代谢笼中进行 3 种饲粮处理，每个处理 6 头。使用无氮饲粮估计 CP 和 AA 的基础内源性损失。2 种玉米的 CP 和所有 AA 的 AID 和 SID 值没有差异。实验 3 用于测量 2 种玉米中磷的表观全肠道消化率（ATTD）和标准全肠道消化率（STTD）值。18 头生长育肥猪（初始 BW 30.5±0.5 kg）来自 6 窝，采用随机完全区组设计，按 BW 和窝分配到 6 头猪的 3 种饲粮处理中。2 种饲粮基于 2 种玉米，使用无磷饲粮测量内源性磷损失。PTC 饲粮的 ATTD 和 STTD 值（分别为 71.4%和 76.9%）高于 CC 饲粮（分别为 27.6%和 33.4%）（P<0.05）。饲喂 PTC 饲粮的猪的磷保留率（P 保留率）高于饲喂 CC 饲粮的猪（P<0.05）（分别为 70.7%和 27.1%）。结果表明，PTC 对生长猪的能量和磷消化率高于 CC。因此，如果 PTC 在猪饲粮中替代 CC，饲粮的 DE 和 ME 将增加，并且需要向饲粮中补充更少的无机磷，从而减少粪便中的磷排泄。
