Influence of formaldehyde on the intestinal microflora of redclaw crayfish

The redclaw crayfish ( Cherax quadricarinatus ), a highly valued freshwater aquaculture species, is renowned for its rapid growth, environmental adaptability, and nutritional quality. However, the intensification of aquaculture practices has led to increased disease outbreaks, prompting the widespread use of disinfectants such as formaldehyde. While formaldehyde is effective against bacterial, parasitic, and fungal infections, its impact on the gut microbiota of redclaw crayfish remains poorly understood. This study employed metagenomic sequencing to investigate the effects of formaldehyde exposure on the gut microbial community of redclaw crayfish. Results revealed significant alterations in microbial diversity and structure, with a marked decrease in beneficial bacteria and an increase in potential pathogens. Fungal and archaeal communities were also affected, with shifts in dominant taxa such as Zygotorulaspora and Haloarcula . Functional analysis indicated disruptions in metabolic pathways related to amino acid metabolism, carbohydrate metabolism, and immune response. These results indicate the regulatory mechanism of formaldehyde exposure on the structure and functional characteristics of the intestinal microbial community of red claw crayfish, revealing the multiple effects of formaldehyde on the host body by changing the composition of gut microbial, interfering with metabolic pathways, and destroying the balance of microecology.