Ammonia Exposure Elevated 5-HT Expression, Reprogrammed Transcriptome and Microbiota Community in Yellow Catfish (Pelteobagrus fulvidraco) Gill During Early Ontogeny

-which were renowned for exceptional stress resistance capacity-decreased after ammonia exposure. Thus ammonia exposure disrupts the transcriptomic and microecological balance within gill mucosa, which may elevate the risk of pathogenic infection. Overall, our study provided the first evidence of serotonergic regulation on early fish respiration during ammonia exposure, and also offered new theoretical insights into the involvement of microorganisms in ammonia toxicity.