Social buffering is a phenomenon where the presence of conspecifics reduces an animal's stress response. Well known in mammals, social buffering was recently described in fishes exhibiting pronounced social hierarchies. Lake sturgeon (Acipenser fulvescens) are a gregarious rather than hierarchical fish. Therefore, we tested their capacity for social buffering following exposure to an acute thermal stress. Isolated or grouped (three or six similarly sized conspecifics) age-0 lake sturgeon were exposed to a critical thermal maximum (CT_max) test. We measured the endocrine and cellular response to acute thermal shock by assessing whole body cortisol concentration and mRNA expression of steroidogenic acute regulatory protein (StAR) and heat shock proteins (hsp90a, hsp90b, and hsp70) during recovery from the CT_max test. Isolation or grouping had no effect on CT_max. Whole body cortisol concentrations in isolated fish were approximately three-fold higher than in grouped fish 1 h post-CT_max and two-fold higher than grouped fish 20 h post-CT_max. Similarly, 1 h post-CT_max, mRNA expression of StAR, hsp90a, hsp90b and hsp70 were three to four-fold higher in isolated fish compared to groups of three and six fish. At 20 h post-CT_max, expression of StAR was approximately two-fold higher in isolated fish, but expression of hsp90a, hsp90b, and hsp70 was not significantly different between isolated and grouped fish. While conspecific presence had no effect on CT_max, the significant reduction of endocrine and cellular stress markers post-CT_max in grouped fish strongly suggests that lake sturgeon may use social buffering to combat potential deleterious effects of exposure to heat stress.

社会缓冲是一种现象，其中特定物种的存在降低了动物的应激反应。在哺乳动物中众所周知，最近在表现出明显社会等级的鱼类中描述了社会缓冲。st鱼（Acipenser fulvescens）是一种群居而不是等级鱼类。因此，我们测试了他们在暴露于急性热应激后的社会缓冲能力。隔离或分组（三个或六个相似大小的同种菌）的0岁湖lake鱼接受了最大热最大（CT _max）测试。我们通过评估全身皮质醇浓度和类固醇生成的急性调节蛋白（StAR）和热休克蛋白（从CT _max测试恢复期间的hsp90a，hsp90b和hsp70）。隔离或分组对CT _max无影响。在分离的鱼全身皮质醇浓度约为3倍在分组鱼1小时后CT更高_最大值和两个倍分组鱼20小时后CT更高_最大。相似地，与三只和六只鱼的组相比，CT _max 1 h后，分离出的鱼中StAR，hsp90a，hsp90b和hsp70的mRNA表达高三至四倍。CT _max后20 h ，StAR的表达在分离的鱼中大约高出两倍，但是分离的鱼和分组的鱼中hsp90a，hsp90b和hsp70的表达没有显着差异。尽管同种存在对CT _max没有影响，但是在成群鱼类中CT _max后内分泌和细胞应激标志物的显着减少强烈表明，湖st鱼可能利用社交缓冲来对抗暴露于热应激的潜在有害影响。