Coated crystalline essential amino acid supplementation supports high soybean meal inclusion in diets for Nile tilapia (Oreochromis niloticus) with improved protein retention and nutrient assimilation
The aquaculture industry has previously relied on high-quality fishmeal (FM) to produce diets of excellent standards. However, plant-based proteins such as soybean are more cost-effective for low-value fish species, for example, tilapia and carp, and fishmeal use has been significantly diminished. Previous studies have mainly addressed standard soybean meal (SBM) sources in aquafeeds. A 55-day feeding trial was conducted to investigate the replacement of fish meal with soybean meal concentrate in Nile tilapia ( Oreochromis niloticus ) using a semi-purified diet approach against a Low Temperature (LT) fishmeal as a primary reference protein. Four diets with different levels of soybean meal were evaluated and compared to a control diet of 100 % fish meal. Three diets containing 20, 40, and 80 % soybean protein concentrate (SBPC) were examined. The fourth diet consisted of 80 % SBPC and two essential amino acids: lysine and methionine (80SBPCAA) in a coated form. The average daily growth