Abstract：
1. This study was conducted to determine the effects of graded levels of phytase on the performance, egg quality and gut health of white laying hens.2. Treatments consisted of a negative control (NC) diet containing 0.14% available phosphorus (avP), positive control (PC) diet containing 0.35% avP provided via dicalcium phosphate (DCP) and DCP replaced in the PC by with three graded levels of phytase derived from Komagataella phaffii at 500 (PC-500), 750 (PC-750) and 1000 (PC-1000) FTU/kg which provided 0.176%, 0.188% and 0.200% of avP, respectively.3. Egg production, feed intake, feed conversion ratio and jejunal morphometry were negatively affected in NC-fed birds (p < 0.05). Considering the whole period, birds fed a diet supplemented with graded levels of phytase shared the same egg production and feed intake levels with PC birds (p < 0.05). Feed conversion ratio was significantly lowered by 4.9%, 1.6% and 7.6% in hens fed on diets PC-500, PC-750 and PC-1000, respectively compared to those fed the PC (p < 0.05).4. Neither of the dietary treatments affected cracked eggs, dirty eggs, eggshell breaking strength and eggshell thickness. Dietary supplementation of phytase significantly increased villus surface area by 15%, 36% and 40% in PC-500, PC-750 and PC-1000 birds, respectively compared to PC (p < 0.05).5. A significant increase in lactobacillus count was observed in line with increasing the level of phytase (p < 0.05). Dietary treatments had no effect on the caecal coliform or aerobic populations. Furthermore, phytase supplementation significantly increased the concentrations of total caecal short-chain fatty acid (SCFA; p < 0.01).6. In conclusion, along with improving performance parameters, the inclusion of phytase in laying hen diets can ameliorate intestinal morphology and stimulate caecal microflora and increase SCFA concentrations.
摘要：
1.这项研究是为了确定植酸酶的分级水平对性能的影响，白蛋鸡的蛋品质和肠道健康2.治疗包括含有0.14%有效磷(avP)的阴性对照(NC)饮食,阳性对照（PC）饮食中含有0.35％的avP，通过磷酸二钙（DCP）和DCP在PC中被三个分级水平的植酸酶所替代，这些植酸酶来自于500（PC-500）的Komagataellaphafii，750（PC-750）和1000（PC-1000）FTU/kg，提供0.176%，AVP的0.188%和0.200%，分别.3.鸡蛋生产,饲料摄入量，在NC喂养的鸟类中，饲料转化率和空肠形态计量学受到负面影响（p<0.05）。考虑到整个时期，饲喂添加分级水平植酸酶的日粮的禽类与PC禽类具有相同的产蛋量和采食量(p<0.05)。饲料转化率显著降低4.9%,与饲喂PC的母鸡相比，饲喂PC-500，PC-750和PC-1000的母鸡分别为1.6％和7.6％（p<0.05）。两种饮食处理都不影响破裂的鸡蛋，脏鸡蛋,蛋壳断裂强度和蛋壳厚度。日粮补充植酸酶使绒毛表面积显著增加15%,36％和40％在PC-500，PC-750和PC-1000鸟，分别与PC相比(p<0.05)。观察到乳杆菌计数的显著增加与植酸酶水平的增加一致(p<0.05)。饮食治疗对盲肠大肠杆菌或有氧人群没有影响。此外，植酸酶显著提高了盲肠总短链脂肪酸浓度(SCFA;p<0.01)。总之,随着性能参数的改善，在蛋鸡日粮中加入植酸酶可以改善肠道形态，刺激盲肠微生物区系并增加SCFA浓度。
