The Composition and Diversity of Intestinal Microbes at Different Growth Stages of Giant Freshwater Prawns (Macrobrachium rosenbergii)

Abstract

Intestinal bacterial communities play an important role in the growth and health of aquatic animal hosts and have drawn increasing attention. However, the role of the intestinal microbiota in the growth of freshwater prawns remains unclear. Here, the intestinal microbiota of freshwater prawns (Macrobrachium rosenbergii) at different life stages (one, two, and three months old) were investigated using 16S rRNA sequencing. The results showed that community richness and diversity increased with growth, which might be one of the reasons that the prawns maintained a fast growth rate before sexual maturation. Three core phyla were identified in the one-month-old group, namely, Firmicutes (79.24%), Proteobacteria (17.09%) and Actinobacteriota (2.01%). Five core phyla were identified in the two-month-old group, including Firmicutes (47.84%), Proteobacteria (44.22%), Actinobacteriota (1.83%), Acidobacteriota (1.66%) and Bacteroidota (1.24%), and the core phyla in the three-month-old group were similar, except for Acidobacterota, which was not identified. A total of 12 core genera were identified in all samples, and significant differences were observed in the relative abundance of gut microbiota between the three groups (p < 0.05). Exiguobacterium, Lactococcus and Shewanella were the three most significantly differentially abundant genera between stages. In addition, Candidatus Hepatoplasma was detected only in the two- and three-month-old prawn groups. This study provides information on the differences in the intestinal microbiota in different developmental stages, which contribute to adaptation to salinity in the early developmental stage and digestive ability to meet the growth needs of Macrobrachium rosenbergii.