Feed samples
were collected and pooled at regular intervals during the
experimental period and ground using a 1-mm screen
before analyses. Feed and fish body were analysed for
dry matter through drying samples for 24 h at 103°C until
constant weight [22]. Ash content was determined by
incineration in a muffle furnace for 4 h at 550°C [23]. Crude
protein (N×6.25) was measured by the Kjeldahl method
after acid digestion according to [20]. Lipid was extracted
by petroleum ether extraction in a Soxhlet apparatus.
Carbohydrate fraction was determined as dry matter minus
fat, protein and ash in the feed.