Strain-specific changes in the gut microbiota profiles of the white shrimp Litopenaeus vannamei in response to cold stress

The gut microbiota is closely related to shrimp growth and health. However, the response patterns of gut bacterial communities to environmental stresses (such as cold) in distinct shrimp strains and their association with host status are still unclear. In this study, stress tolerance and its potential association with the gut microbiota in two white shrimp Litopenaeus vannamei strains (ZT and PM) were investigated using 16S rRNA gene amplicon sequencing. The stable body weight of PM relative to the obvious weight loss of ZT after both were subjected to cold stress (at the adult life stage) suggests that PM possess stronger tolerance to cold stress. Meanwhile, the alpha-diversity indices of PM gut bacteria were significantly higher than those of ZT, and the bacterial community structure in the PM gut was more stable as well. Furthermore, cold stress led to domination of the bacterial composition in the ZT gut by the families Erysipelotrichaceae, Mycoplasmataceae, and Vibrionaceae, which have potential pathogenic members. On the other hand, the relative abundances of 18 discriminatory families, represented by Rhodobacteraceae (33.8%), in the PM gut were significantly higher than those in the ZT gut, suggesting that distinct gut bacterial assemblages may reflect the stress resistance potential of shrimp. The taxonomic signature of gut microbiota of the cold-resistant strain could be a guidance for isolation of novel probiotics from bacterial groups such as Rhodobacteraceae, which could be potentially applied to reduce the influence of cold stress in white shrimp.