The influence of sex on the intestinal flora of Procypris mera

Abstract

Sex plays a significant role in the formation of gut microbiota in most fish species. Procypris mera, a freshwater fish of considerable economic value, has been the subject of limited research regarding sex differences in gut microbiota. This study employed 16S rRNA technology to analyze the gut microbiota of P. mera under identical breeding conditions. The analysis revealed that, despite no significant differences in overall diversity between different sexes in the same intestinal segment, there were significant sex-related differences in specific microbial phyla and genera. Specifically, Fusobacteriota showed significant differences in relative abundance in the hindgut of females and males. Similarly, Cetobacterium exhibited significant differences in relative abundance in the hindgut of females and males. Additionally, there were significant differences in the Shannon index between the foregut and hindgut in males, as well as significant differences in beta diversity among the foregut, midgut, and hindgut in males. These findings indicate that there are local differences in gut microbiota between different sexes in the same intestinal segment and between different intestinal segments in the same sex. This discovery not only helps to reveal the mechanisms by which sex affects the formation of gut microbiota in fish but also provides new insights and theoretical support for optimizing breeding conditions and improving fish health.