title: Evaluation of gaseous concentrations, bacterial diversity and microbial quantity in different layers of deep litter system.
abstract: 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 ofEscherichia coli,Lactobacilli,Methanogenswere performed in this paper.
  
  
  RESULTS
  The concentrations of CO2, CH4, and NH3in the deep litter system increased with the increasing of depth while the N2O 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 ofEscherichia colireached the highest value at the surface beddings and there was a significant drop at the -20 cm layer with the increasing depth. TheLactobacillinumbers increased with the depth from 0 cm to -15 cm and then decreased significantly under the -20 cm depth. The expression ofMethanogensreached its largest value at the depth of -35 cm.
  
  
  CONCLUSIONS
  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.
authors.affiliation: College of Animal Science & Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory Animal Center, Dalian Medical University, Dalian 116000, China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Wang
authors.affiliation: Laboratory Animal Center, Dalian Medical University, Dalian 116000, China.
authors.forename: Fujin
authors.initials: F
authors.lastname: Wang
authors.affiliation: Laboratory Animal Center, Dalian Medical University, Dalian 116000, China.
authors.forename: Aiguo
authors.initials: A
authors.lastname: Wang
authors.affiliation: College of Animal Science & Technology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Peishi
authors.initials: P
authors.lastname: Yan
keywords: Bacterial Diversity; Deep Litter System; Environment; Gases Concentrations; Microbial Quantity