A broader look at ammonia production excretion a

Authors: Carol Bucking

Publish Date: 2016/08/13

Volume: 187, Issue: 1, Pages: 1-18

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Abstract

For nearly a century researchers have studied ammonia production and excretion in teleost fish Stemming from past investigations a body of knowledge now exists on various aspects including biochemical mechanisms of ammonia formation and specific routes and tissues used for ammonia transport culminating in a current detailed theoretical model of branchial transport including the molecular identities of the moieties involved However typical studies examining ammonia balance use routine laboratory conditions and fasted fish While avoiding additional variables that influence nitrogen balance these studies are arguably idealistic and do not reflect the natural variety of conditions that fish encounter Further studies have revealed the impacts of extrinsic factors eg salinity pH temperature on ammonia handling in fasted fish whereas others have explored intrinsic factors such as life history and developmental impacts One routine challenge for ammonia balance that fish encounter is feeding and digestion Fortunately many new studies have revealed the impact of feeding and digestion on several aspects of ammonia balance from production to excretion and to transport and several have done so incorporating supplemental extrinsic and/or intrinsic factors Together these complex studies reveal realistic responses to multifactorial challenges encountered by animals in the wild and begin to provide a holistic view of ammonia balance in freshwater teleost fish

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