Heat-treated bean (Phaseolus vulgaris) residue meal as an alternative protein source in pelleted diets for Nile tilapia fingerlings: growth, body composition, and physical characteristics of diets

The study aimed to evaluate heat-treated bean residue meal ( Phaseolus vulgaris )—BRM—as an alternative protein source in diets for Nile tilapia fish. A completely randomized design was used, totaling four ( n = 4) dietary treatments: diet without BRM (CON), raw BRM (RBRM) and heat-treated BRM at 100 °C for 15 min (BRM15), and 30 min (BRM30) before inclusion in diets. Nile tilapia fingerlings (1.3 g initial weight) were hand-fed the experimental diets for 66 days, divided equally into three meals per day. Performance parameters, body composition, nutrient retention, and physical characteristics of diets were evaluated. Growth and feed conversion were lower ( P < 0.05) in fish fed BRM. Protein productive value was higher ( P < 0.05) in fish fed CON diet than in fish receiving BRM. However, 30 min heat treatment of BRM increased ( P < 0.05) protein retention in fish. Fish fed BRM30 also had higher protein content ( P < 0.05) and reduced body lipid content ( P < 0.05) than those fed CON diet. The physical characteristics (durability, dry matter leaching, waterproof time, and water stability time) were significantly improved ( P < 0.05) in the BRM30 diet compared with other dietary treatments. The dietary inclusion of BRM at the level of 15% is not recommended for tilapia due to low growth performance and feed efficiency, regardless of preheating treatment. However, research on longer heat treatment time is needed due to the improvements observed in nutrient retention and physical characteristics of diets.