Performance, environmental and economic outcomes of stepwise hybrid rye in broiler diets

This study evaluated the performance, technological, environmental, and economic outcomes of stepwise inclusion of KWS Tayo hybrid rye grain in enzyme-free broiler diets. The experiment was conducted using Ross 308 broiler chickens, which were allocated to five groups at 10 days of age. The control group received diets without rye, whereas the experimental groups received rye according to stepwise inclusion schemes of 2/4/10 %, 3/6/15 %, 4/8/20 %, and 5/10/25 % during days 11–20, 21–30, and 31–42, respectively. Body weight gain, feed intake, feed conversion ratio, water-to-feed ratio, survival rate, the carbon footprint of diets and feed production, and economic return were assessed. The groups were also ranked using an integral efficiency index that combined the key performance, technological, environmental, and economic criteria. The 3/6/15 % scheme provided the best balance between growth performance and environmental impact. This group had the highest body weight gain (2552.32 g), the numerically best feed conversion ratio, the lowest water-to-feed ratio, the lowest carbon footprint per kilogram of gain (0.808 kg CO₂-eq.), and the highest integral efficiency index. The 2/4/10 % scheme was the most advantageous in terms of economic return, whereas the maximum 5/10/25 % scheme, despite high survival and a potential reduction in feed-related emissions, did not provide an overall advantage because of lower gain, poorer feed conversion, and an increased water-to-feed ratio. These results indicate that moderate rather than maximum stepwise rye inclusion levels are preferable in enzyme-free broiler diets. The 3/6/15 % scheme is recommended when the priority is to combine growth performance, feed efficiency, and environmental efficiency, whereas the 2/4/10 % scheme may be more suitable when economic return is the main criterion.