As the prices of fish feed ingredients continue to soar due to economic and
environmental challenges, many fish farmers now produce practical fish diets deficient in
protein, to minimize costs and maximize profits. This study evaluated the effects of such diets
on the growth performance and carcass quality of African catfish,
Clarias gariepinus
. Five
dietary treatments used contained 25%, 30%, 35%, 40% and 45% protein, respectively. Fish
were fed for 70 days and the results showed high and improved growth performance in relation
to the increasing dietary protein levels. Carcass protein, ash and minerals correlated positively
with increasing dietary protein levels while the lipids had inverse relationship. Generally, fish
fed diets of 25-35% protein had lower performance than those fed the control diets of 40 or 45%
protein reported as the requirements for the fish. However, and in all cases, there were no
differences in the performance of fish fed 40 or 45% protein diet, indicating no significant
additional benefits from feeding the fish with 45% protein diet. The results also suggested the
protein requirement of the fish to be above 35% and about 40%. The carcass protein-ash ratio
was observed to be constant and ranged between 4.08 and 4.82.
