Effects of Enterococcus faecalis on egg production, egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with Enterococcus faecalis (EF) on egg production, egg quality and caecal microbiota. A total of 360 Hy-Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 3.75 · 10⁸ cfu EF/kg (Group I) or the basal diet + 7.5 · 10⁸ cfu EF/kg (Group II). The experiment lasted for 45 d. Eggs and caecal samples were collected at the end of the experiment. Results showed that dietary supplementation with EF did not affect the average daily egg weight, cracked egg rate, mortality and egg quality. However, EF supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p < 0.05). The differences in caecal microbiota between Group II and the Control were significant. The relative abundance of Verrucomicrobia and Cyanobacteria at the phylum level, Rikenellaceae, Christensenellaceae and Veillonellaceae at the family level, and the Faecalibacterium, Christensenellaceae R-7 group and Eubacterium coprostanoligenes group at the genus level changed significantly in Group II compared with the Control (p < 0.05). In conclusion, the tested dietary supplementations with EF improved product performance and affected the caecal microbial community structure of laying hens during the late laying period.