Growth performance in Clarias gariepinus Burchell fingerlings fed blood meal–bovine rumen digesta blend diets
The nutritive value of blood meal-bovine rumen digesta (BMBRD) as a potential protein source in the diet of the African catfish Clarias gariepinus Burchell was evaluated using 144, six-weeks old C. gariepinus fingerlings
(10.32±1.96 g) with a view to producing a cheap fish feed. Five approximately iso-nitrogenous (35% crude protein) experimental diets were prepared with 0%, 25%, 50%, 75% and 100% BMBRD meal inclusion
respectively to replace the fishmeal standard component of the control commercial diets. The prepared experimental diets were fed in duplicate to C. gariepinus fingerlings in each dietary group for 86 days. A commercial feed was exclusively fed as the control diet. The fish stocked in 12 glass tanks (60 cm x 30 cm x 30 cm) at the rate of 12 fish per tank were fed at the rate of 5% of their body weight per day, in two equal instalments. The highest weight gain (68.07 ±2.70 g) was recorded in the fish fed the control diet followed by the fish fed 50% BMBRD diet (57.68±10.52 g) while the least weight gain occurred in the fish fed 100% BMBRD diet. However, the mean weight gain of the fish fed 75% and 100% BMBRD diet were significantly different (P<0.05) from the mean weight gain of fish fed other experimental diets. The fish fed 50% BMBRD diet had better protein
efficiency ratio (PER) (0.32 ±0.01%), feed conversion ratio (FCR) (0.86 ±0.12) and specific growth rate (SGR) (1.03 ±0.07%) than the fish fed the other test diets. However, there was no significant difference (P>0.05) in the mean SGR of the fish fed experimental diets and the control. The proximate composition of the carcass of the fish fed the different experimental diets showed that the protein content of the fish fingerlings fed the control feed was significantly higher (P<0.05) than in the fishes fed the experimental diets. The study concluded that fishmeal could be adequately replaced with BMBRD meal of up to 50% in C. gariepinus fingerlings diets without obvious deleterious effects on growth and survival.
Keyword: Blood meal, rumen digesta, Clarias gariepinus, diet.