Toxic effects of ammonia on intestinal health and microbiota in red-eared slider (Trachemys scripta elegans)

Gut Microbial Composition and Liver Metabolite Changes Induced by Ammonia Stress in Juveniles of an Invasive Freshwater Turtle

“…Decreased intestinal microbial community diversity in ammonia-exposed T. scripta elegans was shown in a previous study [ 18 ], but was not found in the present study. Discrepant findings might partially result from the differences in ammonia exposure level, the age stage of experimental animals, and the rearing environmental condition in the two studies (e.g., a relatively higher ammonia level: approximately 32 mg/L total ammonia-N, and older individuals were used in the previous study [ 18 ]). In fact, between-species comparison also displayed inconsistent ammonia impacts on intestinal microbial diversity.…”

“…Specifically, some pathogenic bacterial genera belonging to Proteobacteria, such as Aeromonas and Pseudomonas , were significantly increased in ammonia-exposed turtles, potentially indicating an unhealthy intestinal state. Other metabolism- or immunity-related bacterial genera, such as Romboutsia and Clostridium_sensu_stricto , were shown to decrease in ammonia-exposed T. scripta elegans in the previous study [ 18 ]. However, among-group differences in the abundances of these genera were not statistically significant, which might be due to relatively lower ammonia levels used here.…”

“…As important aquaculture species, some freshwater turtles have been widely cultured in some countries. However, studies considering the impacts of aquaculture environmental pollutants, including ammonia-N, remain limited to only a few turtle species [ 10 , 17 , 18 , 19 , 20 , 21 ]. Specifically, the physiological responses and defense mechanisms to ammonia stress are relatively better understood only in the aquatic Chinese soft-shelled turtle, Pelodiscus sinensis [ 17 , 22 , 23 , 24 , 25 ], but not in other semi-aquatic turtle species.…”

“…As one of the most successful invasive species worldwide, it could be expected that T. scripta elegans might have a great resistance to ammonia stress relative to other species. Nevertheless, a previous study showed that exposure to high concentrations of ammonia would cause marked toxic effects on various tissues in T. scripta elegans , such as damaging intestinal structure and altering its microbial community [ 18 ]. Investigating other physiological responses, such as metabolome responses in various tissues, may contribute to unraveling more mechanisms behind the toxic actions of ammonia, and the physiological adaptations to ammonia in this species.…”

Ammonia nitrogen stress damages the intestinal mucosal barrier of yellow catfish (Pelteobagrus fulvidraco) and induces intestinal inflammation

“…Khan et al (Khan et al, 2021) reported that ammonia nitrogen exposure caused significant downregulation of claudin and occludin in Mauremys sinensis. Similarly, Ding et al (Ding et al, 2021) found that ammonia nitrogen stress resulted in sparse and shortened intestinal villi, downregulation of tight junction genes, and increased cell permeability in Trachemys scripta elegans. In this study, compared with the control group, the intestinal villi of yellow catfish in the ammonia nitrogen exposure group were sparse and shorter, the cavities between the microvilli were obvious and the tight junctions were blurred.…”