Fish gill is very sensitive to physical and chemical
alterations of the aquatic medium and to any change in the
composition of the environment which is an important
indicator of water borne toxicants (Ogundiran et al.,
2009). Fish gill also play a vital role, as they are the main
sites of gaseous exchanges, which involved
osmoregulation, acid-base balance, excretion of
nitrogenous compounds (Pereira and Caetano, 2009) and
harbors many microbes. This is because they are directly
in contact with the aquatic habitat. From a morphological
and physiological point of view, the gill is very complex
organ, involved not only in gas exchange, ion exchange
and acid-base balance, but also in nitrogenous waste
excretion, such as ammonia and urea