FEED INTAKE AND DIGESTIBILITY OF NUTRIENTS IN RATIONS, WITH SEVERAL FEED COMBINATIONS, BY TILAPIA FISH (0.niloticus)

The digestion coefficient of several different combinations were determined in this study by tilapia (O.niloticus) fish in order to extract the proximate figures for the digestibility of different nutrients (organic matter, protein, fat, fibre, nitrogen-free extract and energy). Fourteen digestion experiments were performed using 14 experimental rations which formulated from different feedingstuffs (fish, meat, poultry by-products, earthworm, soybean, cottonseed and poultry manure meals, corn, wheat bran, middlings and berseem hay). Fish were fed twice daily to satiation and the experiments were lasted for one month. Faecal samples were collected by syphoning and
tion of the faecal matter from the aquarium. The amount of feed consumption for fish satiation depends on the quality of diets according to fibre percentage or imbibition ability of water. The digestibility of crude protein over a range of 80-91% (x =86%) by tilapia which depends on the source of protein, and the rations with high percentages of fish meal and soybean meal had the highest digestion coefficients. The digestion coefficient for fat ranged from 83 to 85% (X=84%), and the diets containing high levels of fat gave high values for digestibility of fat. For carbohydrates, the digestion coefficient of nitrogen-free extract ranged from 73% to 87% ( =78%), while for fibre from 71 to 85% (X=79%), and diets which contained cottonseed meal, wheat middlings and berseem hay had the lower carbohydrates digestibility. The digestion coefficient for energy ranged from 61 to 71% (x =66%) and the ration contained fish oil gave high values. It could be concluded that, these average figures can be used as a guide in the formulating diets to satisfy tilapia fish needs.