Digestibility Characteristics of Selected Feed Ingredients for Developing Bespoke Diets for Nile Tilapia Culture in Europe and North America

The apparent digestibility coefficients of dry matter (ADC DM), protein (ADCp), essential amino acids (ADC EAA), and energy (ADCe) for Nile tilapia of a selected range of animal and plant feed ingredients found in Western European and North American markets were determined. The investigation was able to provide useful data and information as a prelude for effective diet formulation for this fish species. A reference diet was used for the basis of assessing hydrolyzed fish protein concentrate (CPSP), full‐fat soybean meal (FFSBM), solvent‐extracted soybean meal (SESBM), maize gluten meal (MGM), poultry meat meal (PMM), hydrolyzed feather meal (HFM), and spray‐dried hemoglobin meal (SDHM) by substitution. For each major commercial test ingredient, the ADC were as follows: for plant proteins – FFSBM (ADCp 86.99% and ADCe 74.84%), SESBM (ADCp 93.46% and ADCe 82.16), and MGM which was also utilized well by Nile tilapia (ADCp 83.03% and ADCe 82.36%); for animal proteins – PMM (ADCp 69.30% and ADCe 73.47%), HFM (ADCp 45.53% and ADCe 49.11%), and SDHM was highly digested (ADCp 85.79% and ADCe 75.96%). The ADC EAA reflected the same trends as ADCp, and these varied from >87% on average for the EEA in fish meal, >88% for CPSP, >84% for FFSBM, >63% for SESBM, >83% for MGM, and only 61% for PMM, >63% for HFM, and >77% for SDHM. Highest ADC were obtained with SDHM and SESBM among the animal and plant by‐products tested, respectively. These are discussed in the context of practical diets for tilapia.