Ammonia induced toxico‐physiological responses in fish and management interventions

Abstract Intensification of aquaculture practices resulted in increased ammonia production in the culture systems. Lack of proper management of the culture system will result in elevated ammonia, which adversely affects the culture species. Moreover, with the ongoing global warming, fish metabolism and ammonia excretion are expected to increase. This, coupled with the hypoxic condition, exacerbates the severity of ammonia toxicity. Ammonia toxicity can alter the growth and the biochemical, physiological and immunological responses of fish. Several factors such as pH, temperature, salinity, dissolved oxygen, species and life stages of fish, physical activity, feeding and stress influence the toxicity of ammonia in fish. A proper understanding of these factors is a prerequisite for successful aquaculture. The physiological changes caused by the elevated ammonia hinder homeostasis that eventually increases their susceptibility to diseases. This review discusses ammonia toxicity in fish, factors affecting the toxicity and various physiological, haematological, histological and immunological responses induced by the elevated ammonia. Furthermore, the review summarizes various management and dietary interventions to mitigate ammonia and ammonia induced stress in aquaculture.