Abstract：
There is a gap in the understanding of the relationship between dietary phytate levels and the relative efficacy of phytase to improve amino acid (AA) digestibility in pigs and chickens. Two experiments were conducted to investigate the effect of exogenous phytase on standardized ileal digestibility (SID) of AA and the apparent ileal digestibility (AID) of P in both standard- (SP) and high-phytate (HP) diets for broilers and swine. There were either 40 cages of Cobb 500 male broilers or 10 crossbred barrows (35 kg) fitted with ileal T-cannulas. Both studies were allotted to five dietary treatments (8 replicates). Treatments consisted of four corn-soybean meal-based diets arranged in a 2 × 2 factorial of standard or high phytate and exogenous phytase at 0 or 1 000 phytase units (FYT)/kg; and one N-free diet. Birds were fed a common starter diet from d 0 to 20 and fed experimental diets from d 20 to 25. Birds were euthanized on d 25 via CO2 asphyxiation, and digesta were collected from the terminal ileum. Pigs were fed for a total of four 7-d periods, where digesta were collected on d 6 and 7 of each period. Diet and digesta samples were analyzed for DM, N, Ti, AA, and P to determine AA and P digestibility. The SID of AA was determined by correcting the AID of AA for the basal endogenous losses estimated using the N-free diet. Main effects of the diet type (standard or HP) and phytase (0 or 1 000 FYT/kg), and the interaction of diet type and phytase were evaluated. For both experiments, the HP diets produced lower SID of AA compared to the SP (P < 0.001). For broilers, there was a phytase effect (P < 0.001) for the SID of all AAs evaluated regardless of the diet type. For pigs, phytase improved (P < 0.05) the SID of Met, Lys, Cys, Glu and Ser and tended to improve (P < 0.10) Arg, Leu, Thr, and Tyr. There were no significant interactions for either experiment. For both experiments, AID of P was lower for the HP diets (P < 0.01), and phytase produced greater AID of P for both diet types (P < 0.01). These data indicate that phytase greatly improves the digestibility of P for broilers and pigs and has the ability to significantly increase the digestibility of amino acids for these animals, regardless of the dietary phytate P.
摘要：
对饲粮植酸水平与植酸酶提高猪和鸡氨基酸（AA）消化率的相对功效之间的关系的理解存在差距。进行了两个实验，以研究外源植酸酶对肉仔鸡和猪的标准（SP）和高植酸（HP）日粮中AA的标准回肠消化率（SID）和P的表观回肠消化率（AID）的影响。有40只Cobb500雄性肉鸡的笼子或10只装有回肠T插管的杂交手推车（35公斤）。两项研究都被分配给5个饮食处理(8个重复)。处理包括四种以玉米-豆粕为基础的日粮，以0或1.000植酸酶单位（FYT）/kg的标准或高植酸和外源植酸酶的2×2因子排列；和一个无氮饮食。从d0到20饲喂鸟类的普通起始饮食，从d20到25饲喂实验饮食。第25天通过二氧化碳窒息对鸟类实施安乐死，从回肠末端收集消化物。猪总共喂食了四个7天，在每个时期的第6天和第7天收集消化物。对饮食和消化样本进行了DM分析，N,Ti,AA,和P来确定AA和P的消化率。AA的SID是通过校正AA的AID来确定的，该AID是使用无氮饮食估计的基础内源性损失。饮食类型（标准或HP）和植酸酶（0或1.000FYT/kg）的主要影响，并评价了膳食类型与植酸酶的相互作用。对于这两个实验，与SP相比，HP饮食产生的AASID较低（P<0.001）。对于肉鸡来说，无论饮食类型如何，所有评估的AA的SID都存在植酸酶效应（P<0.001）。对于猪来说,植酸酶改善了Met的SID（P<0.05），Lys,Cys,Glu和Ser趋于改善(P<0.10)Arg，Leu,Thr,和Tyr.对于任一实验都没有显著的相互作用。对于这两个实验，HP饮食中P的AID较低（P<0.01），和植酸酶在两种饮食类型中都产生了更高的磷AID（P<0.01）。这些数据表明，植酸酶大大提高了肉仔鸡和猪的P消化率，并具有显着提高这些动物氨基酸消化率的能力，无论饮食中的植酸盐P.
