Abstract
Heat is a common source of stress in aquatic environments and can alter the physiological and metabolic functions of aquatic animals, especially their intestinal function. Here, the effects of heat stress on the structure and function of the intestine and the characteristics of the intestinal microbiota were studied in sturgeon (Acipenser baerii ♀ × Acipenser schrenckii ♂ hybrid F1). Sturgeons were exposed to sub-extreme (24°C) and extreme (28°C) high water temperatures for 12 days. The heat stress caused systemic damage to the intestine of sturgeons, which displayed severe enteritis in the valve intestine. The microbial diversity analysis showed that heat stress led to the disorder in intestinal microbiota, manifesting as an explosive increase in the abundance of thermophilic intestinal pathogens such as Plesiomonas, Cetobacterium, and Aeromonas and causing physiological dysfunction in the sturgeons. The disorder was followed by significant inhibition of intestinal digestion with reduced chymotrypsin, α-amylase, and lipase activities in the valve intestine and of antioxidant function with reduced peroxidase (POD) and catalase (CAT) activities. Simultaneously, heat stress reduced the thermal tolerance of sturgeons by reducing Grp75 expression and damaged the valve intestine’s repair ability with increased Tgf-β expression. The results confirmed that heat stress damaged the sturgeon intestines obviously and disturbed the intestinal microbiota, resulting in serious physiological dysfunction. The present study investigated the mechanism of the effect of heat stress on the sturgeon intestine and will help develop strategies to improve the resistance to thermal stress for wild and cultured sturgeons.
Highlights
Heat stress in local waters is likely to worsen due to global warming, threatening aquatic animals and potentially altering their behavior, growth, development, reproduction, and digestion (HuiHuang et al, 2012; Miller et al, 2015; Aidos et al, 2020)
Heat stress threatens the survival of cold-water fishes, Sturgeon Intestinal Microbiota Disorder especially for sturgeons whose wellbeing closely relates to the environmental temperature
The number of species and abundance of thermophilic bacteria and fungi were elevated in sturgeons exposed to high water temperatures, which was consistent with the results of the study by Soriano et al on Yellowtail Kingfish in 2018, which showed that increases in ambient temperature increased the diversity of intestinal microbiota
Summary
Heat stress in local waters is likely to worsen due to global warming, threatening aquatic animals and potentially altering their behavior, growth, development, reproduction, and digestion (HuiHuang et al, 2012; Miller et al, 2015; Aidos et al, 2020). Heat stress threatens the survival of cold-water fishes, Sturgeon Intestinal Microbiota Disorder especially for sturgeons whose wellbeing closely relates to the environmental temperature. The abnormally high water temperatures from July to September present an especially difficult challenge for this cold-water fish; and numerous studies have associated immune decline, illness, and death with rising river temperatures (Shen et al, 2014; Castellano et al, 2017; Zhang H. et al, 2019). The present study investigated the potential mechanisms by which heat stress influences the yields of commercial sturgeons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
