Integrated Transcriptome and 16S rDNA Analyses Reveal That Transport Stress Induces Oxidative Stress and Immune and Metabolic Disorders in the Intestine of Hybrid Yellow Catfish (Tachysurus fulvidraco♀ × Pseudobagrus vachellii♂)

Abstract

Live fish are often transported in aquaculture. To explore the effects of transport stress, hybrid yellow catfish (Tachysurus fulvidraco♀ × Pseudobagrus vachellii♂) were subjected to simulated transport treatments (0–16 h) with 96 h of recovery after the 16-h transport treatment, and intestinal biochemical parameters, the transcriptome, and gut microbiota were analyzed. Transportation affected the number of mucus cells and led to oxidative stress in the intestine, which activated immune responses. Changes in lipid metabolism reflected metabolic adaptation to oxidative stress. Toll-like receptor signaling, peroxisome proliferator-activated receptor signaling, and steroid biosynthesis pathways were involved in the transport stress response. Gene expression analyses indicated that transport-induced local immune damage was reversible, whereas disordered metabolism recovered more slowly. A 16S rDNA analysis revealed that transport stress decreased the alpha diversity of the gut microbiota and disrupted its homeostasis. The dominant phyla (Fusobacteria, Bacteroidetes) and genera (Cetobacterium, Barnesiellaceae) were involved in the antioxidant, immune, and metabolic responses of the host to transportation stress. Correlation analyses suggested that gut microbes participate in the transport stress response and the host–microbiota interaction may trigger multiple events in antioxidant, immune, and metabolic pathways. Our results will be useful for optimizing transport processes.

Transcriptome and 16S rRNA Analyses Reveal That Hypoxic Stress Affects the Antioxidant Capacity of Largemouth Bass (Micropterus salmoides), Resulting in Intestinal Tissue Damage and Structural Changes in Microflora

“…Intestinal microbes and hosts can interact with each other [20,21]. We have confirmed this in hybrid yellow catfish (Tachysurus fulvidraco ♀ × Pseudobagrus vachellii ♂) [22]. To determine whether a similar phenomenon would occur under hypoxic conditions, it is necessary to study the correlation between the gut microbiota and the transcriptome.…”

“…Mycoplasma and Enterobacterales are common pathogens in humans and animals [71], and they can strongly induce an inflammatory response in the intestine [72,73]. The increased abundance of these taxa in the Hyp and Rec groups suggests an increased risk of intestinal disease in largemouth bass under hypoxic stress, although there is usually a lag time before such disease outbreaks occur under stress conditions [22]. Cetobacterium is classified as a Fusobacterium.…”

“…To detect correlations between intestinal bacteria and the MAPK signaling pathway, Pearson's correlation analysis was carried out using OmicStudio tool (https://www.omicstudio.cn (accessed on 15 August 2022)) [22]. The P value was corrected for multiple comparisons using R (version 3.6.1); p < 0.05 was considered to be statistically significant, p < 0.01 was very significant, and p < 0.001 was extremely significant.…”