Sunflower Protein Concentrate as an Alternative to Soybean Meal in Broiler Diets: Effects on Growth Performance, Ileal Amino Acid Digestibility, and Intestinal Fermentation

Soybean meal (SBM) is the predominant protein source in broiler diets, but increasing interest in alternative protein ingredients has encouraged the evaluation of processed sunflower products with improved nutritional characteristics. This study investigated the effects of replacing SBM with sunflower concentrate (SFC) on growth performance, apparent ileal amino acid (AA) digestibility, intestinal fermentation metabolites, and economic outcomes in broiler chickens. 576 one-day-old male Ross 308 broiler chickens were assigned to 48 floor pens with four dietary treatments: a control diet containing SBM and diets in which approximately one-third (SFC 1/3), two-thirds (SFC 2/3), or all (SFC 3/3) of the SBM protein was replaced with SFC. Increasing SBM replacement with SFC improved growth performance, with significant linear responses for body weight (BW), BW gain (BWG), and feed conversion ratio (FCR) over the 35-day experimental period (p < 0.01). Apparent ileal digestibility increased linearly with SFC inclusion for indispensable AA and several dispensable AA, as well as total AA (p < 0.05). In the caecum, concentrations of isobutyric acid, isovaleric acid, and total branched-chain fatty acids decreased with increasing SFC inclusion (p < 0.05), indicating reduced proteolytic fermentation. Despite higher feed costs with increasing SFC inclusion, SFC 2/3 provided the most favorable balance between performance and economic return. Overall, SFC effectively replaced a substantial proportion of SBM protein without impairing broiler performance or AA utilization. The combined biological and economic responses indicate that partial replacement, particularly around two-thirds of SBM protein, may provide a more favorable balance than complete replacement under the price conditions evaluated.