To explore the relationship between intestinal microbiomes and asthenospermia.

This was a retrospective case control study. A total of 32 men with asthenospermia and 30 normal men (named control group) were included. The subjects were recruited from Department of Andrology of Shenyang Jinghua Hospital from January 2021 to June 2021. Basic information was collected, semen quality was tested, abundance of intestinal bacteria in feces was detected using 16S rDNA full length assembly sequencing technology (16S-FAST).

In patients with asthenospermia, the total sperm count [112.22×10⁶ (79.13×10⁶, 179.76×10⁶)], forward progressive motility rate [22.93% (16.71%, 28.02%)], non-forward progressive motility rate [5.60% (3.98%, 7.62%)] were significantly lower and immobile sperm rate [72.19% (65.27%,78.92%)] was significantly higher than those of control group [166.76×10⁶ (110.17×10⁶, 262.79×10⁶), P=0.022; 42.37% (35.21%, 57.88%), P<0.001; 8.82% (6.18%,11.14%), P=0.001; 50.88% (33.33%, 56.24%), P<0.001], and there were no significant differences in age and body mass index between the two groups (all P>0.05). The participating population can be divided into enterotype 1 (Bacteroide enterotype) and enterotype 2 (Prevotella enterotype). There was no significant difference in α diversity between asthenospermia group and control group in two enterotypes (all P>0.05). In the population with enterotype 2, β diversity analysis clearly separated the microbiome of men with asthenospermia and healthy controls, and the abundance of Proteobacteria phylum, Clostridium sp., Ruminococcus bromii, Phocea massiensis, C. disporicum, Tyzzerella sp. Marseille_P3062, Howardella ureilytica, C. perfringens, and C. sp. BG-C151 species were more abundant in men with asthenospermia compared with control group [linear discriminant analysis (LDA)>2]; while in the population with enterotype 1, β diversity analysis could not separate the microbiome of men with asthenospermia and non-asthenospermia men (P>0.05). In addition, KEGG analysis showed that in the population with enterotype 2, thiamine metabolism PATH ko00730 pathway, which was closely related to differential bacteria, was significantly less abundant in asthenospermia group than in control group (LDA>2).

The intestinal microbiome and KEGG functional pathways differed significantly between asthenospermia and normozoospermia in population with enterotype 2, while there was no difference in the enterotype 1 population. Changes in intestinal microbiome may have an impact on sperm motility in specific populations.

Asthenospermia; Intestinal microbiome; Infertility