Spent Mushroom Substrate from Pleurotus ostreatus Cultivation as an Alternative Litter Material for Broiler Chickens: Effects on Performance, Welfare, Behavior and Meat Quality

Disposal of by-products from the food industry, such as spent mushroom substrate (SMS) from Pleurotus ostreatus cultivation, poses environmental concerns and its use in animal production may reduce environmental degradation and costs. The aim of the present study was to evaluate SMS as a bedding material in broiler farming. A total of 104 Cobb500 chickens were randomly assigned to an SMS group and a control group, with SMS or wheat straw as bedding material, respectively, and reared for 42 days. Weekly data on performance, litter physicochemical characteristics, welfare and behavior parameters were recorded. On day 42, eight birds per treatment were slaughtered for meat quality and immune parameters evaluation. Utilization of SMS as bedding material increased final body weight by 176 g (3070 g vs. 2894 g, p < 0.05), without significantly affecting the other performance and meat quality traits evaluated (p > 0.05). Reduced footpad lesion, hock burn, cleaner plumage and improved walking ability scores were observed in the SMS group (p < 0.05). The percentage of birds engaged in substrate pecking increased, from 4.97% in the control group to 6.49% in the SMS group, whereas walking and dustbathing behaviors tended to increase (p < 0.1). Among the immunological parameters tested, a higher monocyte percentage, reduced T lymphocyte percentage and elevated heterophil-to-lymphocyte ratio were determined for SMS birds (p < 0.05). In conclusion, SMS is a bedding alternative that may support broiler performance and welfare, contributing to a potential strategy for circular-economy approaches for sustainable poultry and mushroom production systems.