Experimental animals
One hundred and eighty samples of
Oreochromis niloticus were brought to the
laboratory from the University of Ibadan
Department of Wildlife and Fisheries
Management Farm and acclimatized for 14
days in de-chlorinated water, under the
following conditions; water temperature 23
– 25 0C, 12-h light-dark cycle; pH 7.0 – 7.2
. Fishes were fed twice a day with
commercial floating feed containing 30 %
of protein and fed at 3 % of their body
weight as maintenance ration. Faeces and
food debris were siphoned out on a daily
basis and water replaced every 24 hours to
avoid contamination of the fishes before the
beginning of the experiment.