Abstract:
Two diets containing 40% protein, P/E ratio 1.30 g/kcal (high protein) and 34% protein, P/E 1.07 g/kcal (low protein), which
produced the best growth at our previous experiment, were fed to Mystus catfish to determine their carcass quality. The fish
ranging from 40.14 g to 42.64 g in size was grown in commercial fish cages (4x4x1.5 m) at a density of 50 fish per m3 for 90
days. The fish were fed the experimental diets at libitum twice daily, at 9.00 and 16.00. The harvested fish was evaluated for
carcass quality characteristics and growth performance. Edible flash, dressing percentage and water holding capacity of
harvested fish were higher for the fish fed higher protein diet than that for lower protein diet (P<0.05); but carcass waste was
higher for the fish fed lower protein diet than that for higher protein diet (P<0.05). There was no significant different in
hematosomatic index between the two fish groups (P>0.05). Proximate composition of the harvested fish was significantly
different between fish fed higher and lower protein diet, except moisture. Protein and ash composition was higher for fish
fed higher protein diet than that fed lower protein diet (P<0.05), however, fat composition was higher for the fish fed lower
protein diet than for that fed higher protein diet (P<0.05). The fish fed higher protein diet consumed less feed but more
protein (P<0.05); however, feed and protein efficiency as well as protein retention were not different between the two fish
groups (P>0.05). Weight gain was higher for fish fed lower protein diet but protein gain was higher for fish fed higher protein
diet (P>0.05).
