Partial replacement of soybean meal with brown mushroom stem powder: Effects on laying performance, egg quality, and serum biochemical indices of lohmann LSL lite hens.

A total of 120 Lohmann LSL Lite laying hens (34 weeks of age) were used to evaluate the effects of brown mushroom stem (BMS) powder as a partial replacement for soybean meal (SBM) on laying performance, egg quality, egg composition, and serum biochemical parameters. After a 7-d adaptation period, hens were randomly assigned at 35 weeks of age to 1 of 3 dietary treatments: a control diet (0% BMS) and diets in which 10% or 20% of SBM was replaced with BMS. Each treatment had 8 replicates of 5 hens, and the experiment lasted 6 weeks. Data were analyzed using one-way ANOVA with orthogonal polynomial contrasts. Dietary BMS inclusion improved laying performance in an age-dependent manner. Hens fed 20% BMS showed higher egg production (linear P = 0.019) and egg mass (linear P = 0.006) during later stages, with increased egg weight at specific time points. Feed intake increased linearly (P < 0.05), whereas feed conversion ratio was not affected. Egg quality was enhanced by BMS inclusion, primarily through a consistent, dose-dependent linear increase in yolk color across most of the production period (P < 0.05); other egg-quality effects were sporadic and largely confined to single weeks, with albumen proportion increased and yolk proportion decreased at 36 weeks only (linear P = 0.002 and 0.004, respectively). Haugh unit showed a transient increase in 36 weeks only. Eggshell breaking force was unchanged, while shell thickness and shell proportion increased only at isolated later time points (38 and 40 weeks, respectively). Serum biochemical parameters remained within normal physiological ranges, indicating no adverse effects on metabolic health. A linear decrease in aspartate aminotransferase and increase in gamma-glutamyl transferase suggest adaptive metabolic responses rather than hepatic dysfunction. Other indicators of renal function, protein metabolism, electrolyte balance, and energy status were unaffected. In conclusion, replacing up to 20% of SBM with BMS supports performance, improves egg quality traits, and maintains physiological stability, indicating its potential as a sustainable feed ingredient for laying hens.