Evaluation of gaseous concentrations, bacterial diversity and microbial quantity in different layers of deep litter system

OBJECTIVE: An experiment was conducted to investigate the environment of the deep litter system and provided theoretical basis for production. METHODS: The bedding samples were obtained from a pig breeding farm and series measurements associated with gases concentrations and the bacterial diversity as well as the quantity of Escherichia coli, Lactobacilli, Methanogens were performed in this paper. RESULTS: The concentrations of CO(2), CH(4), and NH(3) in the deep litter system increased with the increasing of depth while the N(2)O concentrations increased fiercely from the 0 cm to the −10 cm depth but then decreased beneath the −10 cm depth. Meanwhile, the Shannon index, the dominance index as well as the evenness index at the −20 cm layer was significantly different from the other layers (p<0.05). On the other hand, the quantity of Escherichia coli reached the highest value at the surface beddings and there was a significant drop at the −20 cm layer with the increasing depth. The Lactobacilli numbers increased with the depth from 0 cm to −15 cm and then decreased significantly under the −20 cm depth. The expression of Methanogens reached its largest value at the depth of −35 cm. CONCLUSION: The upper layers (0 cm to −5 cm) of this system were aerobic, the middle layers (−10 cm to −20 cm) were micro-aerobic, while that the bottom layers (below −20 cm depth) were anaerobic. In addition, from a standpoint of increasing the nitrification pathway and inhibiting the denitrification pathway, it should be advised that the deep litter system should be kept aerobic.