C. Hybrid tilapia is a relatively inexpensive seafood source for common households in Taiwan. To maintain low production cost, the protein content of a typical local commercial tilapia diet is approximately 250 g kg-1. Furthermore, it is common practice to totally substitute the plant protein source, mainly soybean meal, for fish meal to reduce the cost of tilapia feed. Therefore, the anti-nutrients in soybean meal may influence the digestibility of the diet to tilapia. (25%)