Effect of Feed Protein : Lipid Ratio on Growth Parameters of African Catfish Clarias gariepinus after Fish Meal Substitution in the Diet with Bambaranut (Voandzeia subterranea) Meal and Soybean (Glycine max) Meal

摘要

Fishmeal (FM) was substituted with soybean meal (Glycine max) (SBM) and bambaranutmeal (Voandzeia subterranea) (BNM) in 10 experimental African catfish, Clarias gariepinus, diets. Feedformulation was designed using mixture model. The inclusion level of the three protein ingredientsvaried between 0% and 60%. Remaining 40% comprised of basal ingredients kept constant for all 10feeds. African catfish of average initial weight 35.2 ± 0.9 g were fed with one of the treatment dietsfor 28 days. The protein:lipid ratios of the diets (range 1.5–3.4:1) were used in evaluating the feedutilization and growth of the fish. We found that catfish performances were mainly depending oningredients and not the ratio itself. The protein:lipid ratios in the diets made of plant ingredientswere high but SGR was low. Specific growth rate (SGR) increased with the increase of feed FMcontent, being ca. 5% day−1 with 60% FM diet but ca. 2% day−1 at both 60% BNM and 60% SBMdiets. SGR was similar (3.5% day−1) with diets of 30% BNM or SBM inclusion with 30% FM. Feedconversion ratio increased from below 0.6 of the 60% FM diet up to 1.5 (60% SBM) and 1.7 (60%BNM). Protein efficiency ratio decreased linearly with increasing FM substitution, but proteinproductive value (PPV) was similar for catfish fed 60% FM diet and its 50% substitution with BNMor SBM. These results suggest that protein:lipid ratio cannot be used in assessing nutritionalperformance if the source of feed ingredient vary widely. However, these results suggest that BNMcan partly substitute FM and completely replace SBM in the diets of African catfish.