The market price of
mustard oil cake is cheaper and contains higher percentage of protein (26.68%) than maize and
red wheat flour. The percentage of mustard oil
cake was increased with rice polish in FM30
and FM25, while maize was greatly replaced by
rice polish and mustard oil cake to maintain the
total protein level (35%) in the experimental
diets. Vitamin and mineral premix (0.2%) were
used in all experimental diet as a supplement of
vitamin and minerals and to make it balanced.
To prepare the diets, ingredients were ground
into small particle sizes and mixed thoroughly.
Water was added to obtain a 25% moisture
level. Diets were then passed through a mincer
with a die and made into 0.4 mm diameter
strands and air dried (24° C) for 24 h. Dry diets
were broken up and sieved to an appropriate
pellet size for the fish (Luquet, 1991). The dry
pellets were stored in frozen (-20 °C) condition
until use. Duplicate samples of each diet were
analyzed for crude protein, lipid, dietary fibre,
ash and moisture contents.