Optimizing the use of dietary emulsifiers and prebiotics in relation to fat source may enhance nutrientutilization efficiency in broiler production. This 42-d study evaluated the effects of an emulsifier (lysophospholipid; LPL) and inulin supplementation in diets with two fat sources on growth performance, nutrient digestibility, muscle fatty acid composition, digestive enzyme activity, and intestinal histomorphology. Eight hundred 1-d-old male broiler chickens were assigned to eight treatments in a 2 × 2 × 2 factorial design with two fat sources (soybean oil or beef tallow), two LPL levels (0 or 1 g/kg), and two inulin levels (0 or 1 g/kg). Interactive effects were detected for fat source × inulin on average daily gain (ADG), mortality, and the European Production Index (EPI), with inulin addition to soybean-oil–based diets yielding superior growth and survival rates (P < 0.05). The LPL × inulin interaction increased feed intake and improved gain-to-feed ratio (P < 0.05). The fat source × LPL interaction significantly influenced lipid-metabolism–related traits (P < 0.05); in tallow-based diets, LPL supplementation increased fat digestibility and AMEn, reduced breast fat deposition, and improved the fatty acid profile of thigh muscle by elevating n-3 PUFA and lowering the n-6/n-3 ratio, whereas no significant effects occurred in soybeanoil–based diets. When interaction terms were not significant, LPL increased protease and lipase activities and improved duodenal villus height and surface area, whereas inulin increased protease activity, improved protein digestibility, and enhanced jejunal villus architecture (P < 0.05). In conclusion, LPL is particularly beneficial in tallow-based diets by enhancing lipid digestibility, energy utilization, and the thigh-muscle fatty acid profile, while inulin improves growth performance, especially in soybean-oil–based diets— offering a practical strategy to optimize broiler production.
