This study aimed to investigate the effects of different levels of the protease DE200TM on the performance, egg quality, organ index and cecum microflora of Hy-line W36 laying hens. In this experiment, a total of 180 laying hens aged 300 days were randomly divided into three treatment groups and fed diets containing 0, 100 or 200 g/t DE200. The experimental period was eight weeks, including two weeks of prefeeding and six weeks of the formal experiment. Regular feeding was performed thrice a day and eggs were collected twice daily, and the feed intake and the egg quality were recorded. The results showed that in terms of production performance, dietary supplementation with different levels of DE200 significantly increased egg production (EP) (P < 0.05) and significantly decreased the feed conversion ratio (FCR) (P < 0.05) and average daily feed intake (ADFI) (P < 0.05) without affecting egg weight (EW). In addition, the addition of DE200 significantly reduced the egg breakage rate (P < 0.05) and tended to increase the Haugh unit and decrease the water content of the yolk (P > 0.05). In the cecal microflora, the addition of DE200 increased the proportions of Bacteroidetes and Firmicutes at the phylum level while reducing the proportion of Fusobacteria. Furthermore, at the genus level, the addition of DE200 increased the proportions of Bacteroides and Faecalibacterium and reduced the proportion of Megamonas. This study suggested that the protease DE200 can be used as a feed supplement to improve the production performance of laying hens.

中文翻译：

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不同添加水平蛋白酶DE200对蛋鸡生产性能、蛋品质及盲肠微生物的影响

本研究旨在探讨不同水平的蛋白酶DE200TM对海兰W36蛋鸡生产性能、蛋品质、器官指数和盲肠微生物群的影响。本试验将180只300日龄蛋鸡随机分为3个处理组，饲喂含0、100、200 g/t DE200的日粮。实验周期为八周，其中预喂两周，正式实验六周。每日3次常规饲喂，每日2次采蛋，记录采食量和蛋品质。结果表明，在生产性能方面，日粮中添加不同水平的DE200显着提高了产蛋量（EP）（P < 0.05），显着降低了饲料转化率（FCR）（P < 0.05）和平均日采食量。摄入量（ADFI）（P＜0.05）而不影响蛋重（EW）。此外，DE200的添加显着降低了鸡蛋的破损率（P＜0.05），并有增加哈夫单位和降低蛋黄含水量的趋势（P＞0.05）。在盲肠微生物区系中，DE200的添加增加了门水平上拟杆菌门和厚壁菌门的比例，同时降低了梭杆菌门的比例。此外，在属水平上，DE200的添加增加了拟杆菌属和粪杆菌属的比例，并降低了巨单胞菌属的比例。本研究表明蛋白酶DE200可以作为饲料补充剂来提高蛋鸡的生产性能。