Analysis and Comparison of Gut Microbiome in Young Detection Dogs

Abstract

The detection dogs are well-known for their excellent capabilities to sense different kinds of smells, which can play an important role in completing various searching and rescuing missions. The recent studies have demonstrated that the excellent olfactory function of detection dogs might be related with the gut microbes via the bidirectional communications between the gastrointestinal tract and the brain. In this study, the gut microbial communities of three types of breeds of detection dogs (Springer Spaniel, Labrador Retriever, and German Shepherd) were studied and compared. The results revealed that the richness and the diversity of gut microbiome German Shepherd dogs were significantly higher than the Labrador Retriever dogs and the Springer Spaniel dogs. At the phylum level, the most predominant gut microbial communities of the detection dogs were comprised of Fusobacteriota, Bacteroidetes, Firmicutes, Proteobacteria, Campilobacterota, and Actinobacteriota. At the genus level the most predominant gut microbial communities were comprised of Fusobacterium, Megamonas, Prevotella, Alloprevotella, Bacteroides, Haemophilus, Anaerobiospirillum, Helicobacter, Megasphaera, Peptoclostridium, Phascolarctobacterium, and Streptococcus. However, the gut microbial communities of the three dogs group were also obviously different. The mean relative abundance of Fusobacterium, Prevotella, Alloprevotella, Megamonas, Bacteroides, and Phascolarctobacterium presented significant differences in the three groups. According to the portraits and characteristics of the gut microbiome in young detection dogs, multiple kinds of nutritional interventions could be applied to manipulate the gut microbiota, with the aim of improving the health states and the olfactory performances.

Keywords: German Shepherd; Labrador Retriever; Springer Spaniel; detection dog; gut microbiota; olfactory function.

Figure 1

Three breed types of detection dogs recruited in this study. (A) Springer Spaniel dog (B) Labrador retriever dog (C) German Shepherd dog.

Figure 2

Venn diagram (A) and the rank–abundance curves (B). There were 244 shared OTUs among the three groups, wherein the OTUs number of German Shepherd group (2,135) was the highest, and then the OTUs number of Labrador retriever group (1,425) was much higher than that of the Springer Spaniel group (398). The vertical axis of the rank–abundance curves showed the percent of OTUs after sampling, while the horizontal axis showed the number of sequences, and the tail length of rank–abundance curves revealed the bacterial community richness.

Figure 3

Alpha diversity analysis of the dog gut microbial community. The richness and diversity estimators of observe, Chao1, ACE, Shannon, Simpson, and J indices were calculated, respectively. The observe, ACE, and Chao1 indices indicated that the bacterial richness of German Shepherd group was much higher than the other two groups, and Shannon and Simpson indices revealed that bacterial community diversity of German Shepherd was the highest.

Figure 4

Plot of PcoA of the dog gut microbial community. The three different groups were segregated into different community clusters.

Figure 5

The compositions of dog gut bacterial community at the phylum (A) and genus (B) levels. Less than 1% abundance of bacterial taxa at the phyla or genus levels was merged into others, and the microbial communities of the three groups differed obviously.

Figure 6

Comparisons of the relative abundance of dog gut microbiota at the genus level. The ordinate indicated the bacterial name at genus levels, and the abscissa indicates the abundance percentage values of the samples.

Figure 7

Heatmap of hierarchy cluster results for the abundance of genus. The genus names of the OTUs are shown on the left, and the different colors of the spots indicated the normalized and log-transformed relative abundance.

Figure 8

PICRUSt functional prediction was performed using EggNOG database, and pathways related to dog gastrointestinal diseases were identified.