Effects of fermented feed on the ammonia emission and microbial community of layer manure compost
The aim of this study is to explore the effects of feeding fermented feed on ammonia emission and bacterial community composition of layer manure compost.The experiment included four groups:a control group(T1)fed the basic diet,and three treatment groups fed the basic diet with 2.5%(T2),5.0%(T3),and 10.0%(T4)fermented feed respectively.The manure of the four groups were collected for aerobic composting trial.The results showed that during the compost process,the temperature of compost initially increased and then decreased.pH values rose from 7.0 to 9.1 at the thermophilic stage.At the end of composting,the seed germination index of T3 and T4 groups was 99.4%and 87.1%,which was higher than that of the T1 group(57.7%)and met the standard of organic fertilizer.The daily ammonia emission of the four groups reached a peak value in the thermophilic stage and decreased gradually at the cooling stage.The total ammonia emission amount of the T3 group was 14.43 mg·kg-1 and was 0.76 mg·kg-1 lower than that of the T1 group.Bioinformatics analysis of bacterial communities showed that the addition of fermentation feed reduced the diversity of layer manure bacteria while increasing the relative abundance of Lactobacillus by 20.61%,6.62%,and 8.13%more than that of the control group,respectively.The main bacteria phyla were the Firmicutes,Bacteroidota,Actinobacteriota,and Proteobacteria.The abundance of the Firmicutes decreased during the composting process while the abundance of other bacteria phyla increased.In conclusion,the application of 5.0%fermented feed in the layer ration raised the relative abundance of the genus Lactobacillus,promoted the layer manure composting maturation,and reduced the total ammonia emission during the process of compost.