Utilizing white mushroom stem powder as a sustainable substitute for soybean meal in layer chick diets

The search for sustainable and cost-effective protein alternatives to soybean meals in poultry diets is a growing priority. White mushroom stems (WMS), a nutrient-dense byproduct of mushroom cultivation, may offer a viable solution due to their content of protein, fiber, and bioactive compounds. This study evaluated the effects of dietary WMS powder on growth, organ development, blood biochemistry, and gas emissions in layer pullets. A total of 160 three-week-old Lohmann LSL Lite pullets were randomly allocated to four dietary treatments containing 0% (control), 2%, 4%, or 6% WMS powder with five replicates of eight birds each. Body weight was recorded weekly, while gas emissions (CO₂, CH₄, and NH₃) were measured using a sensor-based detection system. At the end of a 5-week-long trial, blood and internal organs were collected for further analysis. The inclusion of WMS at levels up to 6% had no significant effect (linear and quadratic P > 0.10) on body weight, weight gain, feed intake, feed conversion ratio, or relative organ weights. Serum biochemical markers, including liver and kidney function indicators, were unaffected by WMS supplementation (linear and quadratic P > 0.10). However, WMS influenced serum mineral profiles, with significant linear or quadratic effects observed for calcium (linear P = 0.019; quadratic P = 0.047), phosphorus (quadratic P = 0.005), sodium (linear P = 0.033; quadratic P = 0.023), potassium (linear P = 0.017), and chloride (linear P = 0.015; quadratic P = 0.026) concentrations. Gas emissions exhibited dose-dependent responses, with CO₂ decreasing linearly (P < 0.001), and NH₃ and CH₄ showing both linear (P < 0.001) and quadratic (P < 0.046) trends. In conclusion, adding WMS up to 6% had no negative impact on bird performance and may help reduce gas emissions, emphasizing its potential as a sustainable alternative to soybean meal in poultry diets.