Abstract
This study aimed to investigate the effects of different levels of the protease DE200 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 d were randomly divided into three treatment groups and fed diets containing 0, 100, or 200 g/t DE200. The experimental period was 8 wk, including 2 wk of prefeeding and 6 wk 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.