Comparative analysis of cutaneous bacterial communities of farmed Rana dybowskii after gentamycin bath.

Qing Tong,Xiaoning Liu,Hongbin Wang,Jia Bie,Xianhao Zhang

doi:10.7717/peerj.8430

Abstract

IntroductionPathogenic bacteria limit the success of Rana dybowskii breeding. Gentamicin is used to treat R. dybowskii disease. To understand the effects of gentamicin on the composition and structure of the cutaneous bacterial community of R. dybowskii, three groups (control, gentamicin and recovery) were established in this study.Materials & MethodsThe V3–V4 hypervariable region of the 16S rRNA gene was analyzed in samples by high-throughput sequencing. Alpha diversity and beta diversity were evaluated to compare the cutaneous bacterial community diversity.ResultsA total of 1,159,668 valid sequences and 3,132 operational taxonomic units (OTUs) were obtained from these three experimental groups. The number of OTUs obtained in the control group, gentamicin group and recovery group were 2,194, 2,288, and 2,047, respectively, and the number of shared OTUs was 1,313. The alpha diversity of the cutaneous bacterial community was not significantly affected by gentamicin, while beta diversity was significantly affected.Discussion & ConclusionsThe effect of a gentamicin bath on relative species abundance was greater than the effect on the species composition. The changes in Proteobacteria, Acinetobacter, and Chryseobacterium were significant, and reductions were observed after the recovery period. Six potentially pathogenic genera were detected, including Aeromonas, Citrobacter, Chryseobacterium, Pseudomonas, Staphylococcus, and Streptococcus. Among them, Aeromonas and Chryseobacterium were significantly inhibited by the gentamicin bath. The results of this study provide a theoretical basis for the application of gentamicin in R. dybowskii breeding.

Highlights

Pathogenic bacteria limit the success of Rana dybowskii breeding
The rarefaction curve tended to be flat, indicating that the samples were sequenced in a reasonable quantity and that the obtained community reflected the vast majority of the actual species (Fig. S1)
Sobs, which represents the actual number of observed operational taxonomic units (OTUs) in each sample, confirmed that the species richness was higher in the gentamicin group than in the other groups (Table 1)

Summary

Introduction

Pathogenic bacteria limit the success of Rana dybowskii breeding. Gentamicin is used to treat R. dybowskii disease. To understand the effects of gentamicin on the composition and structure of the cutaneous bacterial community of R. dybowskii, three groups (control, gentamicin and recovery) were established in this study. The pathogenic bacteria causing these diseases are mostly opportunistic, with an onset season from June to September, which is closely related to the health of the host and the cleanliness of the environment (Xu et al, 2017). Only insects, such as yellow mealworm (Tenebrio molitor), can be used as feed in artificial breeding because R. dybowskii only prey on active food. Further research on the efficacy of using a gentamicin bath may help with this problem

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Results

Conclusion