Comparative analysis of gut bacterial community composition during a single day cycle in Chinese mitten crab (Eriocheir sinensis)

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Feeding time is an important factor affecting the physiological activity and feeding rhythm of crustaceans. However, little is known about the factors and mechanisms contributing to variations in feeding time in aquatic species or their impacts. Moreover, the gut microbiome largely affects host physiology and is associated with diet. To investigate the effects of different feeding times on the composition of intestinal bacterial communities, high-throughput 16S rRNA sequencing was used to monitor the gut bacteria of the Chinese mitten crab Eriocheir sinensis over a 10-day period under different feeding times: 06:00 h, 12:00 h, 18:00 h, and 24:00 h. Weight gain of the day-fed groups was significantly higher than that of the night-fed groups. Two probiotics, Akkermansia muciniphila and Faecalibacterium prausnitzii, were detected in the intestines of crabs in the 12:00 group. In addition, the diversity and richness of the flora in the 12:00 group were slightly higher than those in the other treatment groups. These results collectively indicate that different feeding times change the intestinal flora composition of Chinese mitten crabs, and further identified specific feeding times associated with a more significant weight gain effect. Our findings provide important insights into improving farming strategies for Chinese mitten crabs.

Section: Discussionsupporting

confidence: 93%

Intestinal bacterial community composition of juvenile Chinese mitten crab Eriocheir sinensis under different feeding times in lab conditions

Huang

Zhang

et al. 2022

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“…Previous studies have shown that miRNA expression may be positively correlated with or contrary to corresponding gene expression trends 51 . Combining these data suggest that crab immune response could vary under daily rhythm, possibly upregulated around 18:00, which is consistent with recent studies in our laboratory where diurnal variation in the gut bacterial community of E. sinensis showed that its immune function was more robust at 18:00 52 . Furthermore, we found endopeptidase and catalytic pathways enriched with a large number of putative target genes under circadian.…”

Section: Discussionsupporting

confidence: 92%

Deep sequencing of microRNAs reveals circadian-dependent microRNA expression in the eyestalks of the Chinese mitten crab Eriocheir sinensis

Huang

et al. 2023

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MicroRNAs (miRNAs) are small endogenous non-coding RNAs. In crustaceans, miRNAs might be involved in the regulation of circadian rhythms. Many physiological functions of crustaceans including immunity and hormone secretion exhibit circadian rhythms, but it remains unclear whether specific miRNAs contribute to the alteration of crustacean physiological processes under circadian rhythms. This study investigated the mechanisms of miRNA regulation of circadian rhythms in the Chinese mitten crab (Eriocheir sinensis), one of China's most important aquaculture species. We obtained eyestalks from crab specimens at four time points (6:00; 12:00; 18:00; 24:00) during a 24-h period. We identified 725 mature miRNAs, with 23 known miRNAs differentially expressed depending on the time of day. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that the putative target genes for differentially expressed miRNAs were significantly enriched in the immune response and endocrine-related pathways. Numerous putative target genes are involved in the circadian-related pathways and enriched on circadian-control genes. These results suggest that the expression of miRNAs regulates some specific physiological functions in E. sinensis under circadian cycles. We also profiled various putative target genes enriched under the circadian-related pathway. This study performed miRNA expression in the eyestalks of E. sinensis during a 24-h daily cycle, providing insights into the molecular mechanism underlying crustacean circadian rhythms and suggesting miRNAs' role in studying crustacean physiology should not be overlooked.

“…Briefly, the V3–V4 region of the bacterial 16S ribosomal RNA gene was amplified using PCR with the primers F 5′-ACTCCTACGGGAGGCAGCA-3′ and R 5′-CGGACTACHVGGGTWTCTAAT-3′. The forward primer ITSF (5′-GGAAGTAAAAGTCGTAACAAGG-3′) and reverse primer ITSR (5′-GCTGCGTTCTTCATCGATGC-3′) were used to amplify the fungal internal transcribed spacer (ITS) V1 regions 20 . Thermal cycling consisted of initial denaturation at 98 °C for 5 min, followed by 28 cycles of denaturation at 98 °C for 30 s, annealing at 55 °C for 30 s, and extension at 72 °C for 45 s, with a final extension of 5 min at 72 °C.…”

Section: Methodsmentioning

confidence: 99%

Microbiome and transcriptome analyses reveal the influence of calcined dolomite application on Eriocheir sinensis in a rice–crab co-culture system

Li,

Miao

et al. 2023

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Co-culture systems of rice and aquatic animals can contribute to the ecological intensification of agriculture by reducing nutrient loss and the need for N fertilizer application and by enhancing nutrient-use efficiency. However, the input of high-protein diets into paddy fields, to facilitate the growth of aquatic animals, has been found to increase N pollution and acidification of the soil. Although soil amendments have been widely used to ameliorate acidic soils, reduce N2O emissions, and improve agronomic production, the relationship between soil amendments and aquatic animal remains unclear. Therefore, this study investigated the effects of calcined dolomite (hereafter referred to as dolomite) as an acidic soil amendment and Ca–Mg supplement in rice–crab co-culture using Eriocheir sinensis crabs (Chinese mitten crabs). High-throughput sequencing was used to examine crab bacterial community composition and crab hepatopancreas biology. Although the water pH was significantly increased in the dolomite group, the number, composition, and diversity of bacteria identified in crab gut microbiome did not vary significantly between the dolomite and control groups. In the dolomite group, the probiotic agents Candidatus Hepatoplasma and Lactobacillus were highly abundant in the crab gut, and immune- and retinol metabolism-related genes were significantly upregulated in the crab hepatopancreas. Overall, dolomite application increased crab health and water pH. Dolomite is a low-cost amendment, with better stability, compared to other soil amendments, thus making it ideal for sustainable and clean rice–aquatic animal co-culture.