Temperature-driven alterations in skin microbiota and biochemistry parameters of sturgeons

Abstract

Water temperature constitutes a critical environmental factor that influences the physiological and biochemical processes in fish. Heat stress resulting from global warming negatively impacts the health of fish. Fish skin serves as a crucial defensive barrier for fish. However, limited information exists concerning the impact of heat stress on the skin health of cold-water fish. In this study we analyzed the influence of heat stress on multiple biochemical parameters and microbiota associated with the skin in the hybrid sturgeon (Acipenser baerii ♀ × Acipenser schrencki ♂). Sturgeons were exposed to low (16 °C), normal (22 °C), and high (28 °C) temperatures. The concentrations of total protein (TP), alanine aminotransferase (ALT), creatine kinase (CK), superoxide dismutase (SOD), GST (glutathione S-transferase), and glutathione peroxidase (GSH-Px) in skin mucus did not demonstrate significant alterations across all three groups (p > 0.05). The concentrations of aspartate aminotransferase (AST), alkaline phosphatase (ALP), acid phosphatase (ACP), lactate dehydrogenase (LDH), catalase (CAT), malondialdehyde (MDA), and reduced glutathione (GSH) in mucus on day 5 were significantly elevated in the 28 °C group compared to the 16 °C group (p < 0.05). The concentrations of lysozyme (LZM) in the 28 °C group demonstrated an upward trend, with a significant increase on day 14 (p < 0.05). The concentrations of cortisol, AST, ALP, LDH, CAT, MDA, and GSH in the 28 °C group demonstrated an upward trend, with a significant increase on day 5 (p < 0.05). Moreover, the sequencing of 16S rRNA revealed that heat stress exerts a significant influence on the diversity and community composition of the microbiota present in sturgeon skin mucus. The relative abundance of Actinobacteriota, Bacteroidota, Firmicutes, Pseudochrobactrum, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, and Mesorhizobium in the mucus decreased after heat stress, while the abundance of Fusobacteriota, Enhydrobacter, and Cetobacterium increased. This study revealed the potential ecophysiological responses of sturgeon fish under heat stress conditions, providing guidelines and a roadmap for conservation and aquaculture of sturgeons.