Regulation Effect of Toxocara canis and Anthelmintics on Intestinal Microbiota Diversity and Composition in Dog

Abstract

Toxocara canis is an intestinal roundworm that can cause serious zoonotic parasitic diseases. Drontal Plus^® Tasty (Dog) is a kind of commercial drug used to treat T. canis infection. Febantel, Praziquantel, and Pyrantel pamoate (PP) are its main component. However, there are few studies investigating the impact of Drontal Plus^® Tasty (Dog) and its primary ingredients on the intestinal microbiota of dogs. In this study, we first collected the intestinal content samples of the dogs which administrated with anthelmintics or saline by sterile catheters, then used 16S rRNA high-throughput sequencing technology combined with a variety of bioinformatic analysis methods to analyze the effect of anthelmintics on intestinal microbiota. First, the results of the α and β diversity analysis showed that the abundance and diversity of intestinal microbiota decreased with T. canis infection, and increased after anthelmintic treatment. Then, we found the dominant species (the value of relative abundance > 0.05) was both 28 on phylum and genus levels, besides the most dominant species was Bacillota on phylum level and Segatella and Clostridium_sensu_stricto were most dominant on genus level. Futher analyzing the differences in microbiotal composition on phylum level, we found that Drontal Plus^® Tasty treatment could significantly increase the proportion of Bacillota, while Febantel, Praziquantel, or PP could induce the significantly changes of Bacillota and Bacteroidota. In addition, by analyzing the differences in microbiotal composition on genus level, we found that anthelmintic could significantly decreased the relative abundance of Clostridium_sensu_stricto and significantly increased the abundance of Segatella. However, Drontal Plus^® Tasty had no regulatory effect on the abundance of Segatella. In short, these finding showed that various anthelmintics all have significant effects for changing the abundance and diversity of host intestinal microbiota.

Keywords: Toxocara canis; anthelmintics; intestinal microbiota.

Figure 1

OUT statistical analysis. (A–D) Venn diagram and core-pan OUT map of the unique and shared OTUs among the six groups. (E) Rank-Abundance curves. (F) Rarefaction Curve Analysis. (G) Species accumulation curve. The horizontal coordinate represents the number of sequencing samples, and the vertical coordinate represents the number of OTUs. CI, intestine samples of dogs in the control group; II, intestine samples of dogs in T. canis infected group; TI, intestine samples of dogs infected with T. canis after Drontal Plus^® Tasty treatment group; Febantel, intestine samples of dogs infected with T. canis treated with Febantel; Praziquantel, intestine samples of dogs infected with T. canis treated with Praziquantel; PP, intestine samples of dogs infected with T. canis treated with Pyrantel pamoate.

Figure 2

Comparison of Alpha and Beta diversity index of intestinal microbiota among the six groups. (A) Coverage index. (B) Simpson index. (C) Weighted unifrac. (D) Partial Least−Squares Discriminant Analysis (PLS−DA).

Figure 3

Difference in species composition of microbiota of the six groups on Phylum and genus levels. The horizontal coordinate is the sample name and the vertical coordinate is the relative abundance of the species annotated. Species not annotated at this taxonomic level and whose abundance was less than 0.5% of the sample were combined as “Others” (A,C). The top ten species on phylum level in the six groups were showed in (B). And the top ten species on genus level in the six groups were showed in (D). The significance of the test of difference were marked with * at the top of the bar graph if available, or not marked if not. * indicated the p value ≤ 0.05; ** indicated the p value ≤ 0.01; *** indicated the p value ≤ 0.001.

Figure 4

Correlation between microbiota. Correlation networks of microbiome on phylum showed in (A), each node in the graph represents a species, the larger the area of the point, it means that the average relative abundance of the species is higher; the species are connected to the species using straight lines, the pink color indicates a positive correlation, the blue color indicates a negative correlation, and the thickness of the lines indicate the correlation magnitude (the figure only shows the correlation coefficient between the species is more than 0.2). Heat map of correlation coefficient of microbiome on species was showed in (B). Darker colors indicating stronger correlation between species.