The aim of the study was to test if feeding 15% U. lactuca to broilers, alone or combined with carbohydrases, enhanced meat nutritional quality, without compromising growth performance. One hundred and twenty 22-day-old broilers were allocated to the following diets and replicated 10 times for 14 days: (1) maize and soy-based diet (control); (2) control with 15% U. lactuca (UL); (3) UL diet with 0.005% commercial carbohydrase mixture (ULC); and (4) UL diet with 0.01% ulvan lyase (ULE). Final body weight and average daily gain decreased (p < 0.050) with the ULE diet compared with the control, but no significant differences were found for the other diets. The intestinal viscosity increased (p < 0.001) with all alga diets but was lowered (p < 0.050) in the ileum with the ULE diet, relative to UL and ULC diets. Meat lightness and redness values, off-flavours, and total carotenoids increased (p < 0.001), while yellow values, tenderness, juiciness, overall acceptability, α- and γ-tocopherol, and total lipids decreased (p < 0.001) with alga diets. The n-3 polyunsaturated fatty acids (PUFA) increased (p < 0.050), and the n-6/n-3 PUFA ratio decreased (p < 0.001) with the ULE diet. Total minerals in meat increased (p < 0.001) with alga diets, conversely to sodium and zinc (p < 0.001). Feeding 15% of U. lactuca to broilers did not impair growth but increased meat nutritional value through the accumulation of health-promoting antioxidant carotenoids, n-3 PUFA and total minerals, although reducing overall meat acceptability.
Keywords: Ulva lactuca; broiler; carbohydrase; meat quality; poultry growth.