Nutraceutical Potential of Lentinula edodes' Spent Mushroom Substrate: A Comprehensive Study on Phenolic Composition, Antioxidant Activity, and Antibacterial Effects.

Lentinula edodes, commonly known as shiitake mushroom, is renowned for its potential health advantages. This research delves into the often-overlooked by-product of shiitake cultivation, namely spent mushroom substrate (SMS), to explore its nutraceutical properties. The SMS samples were collected and subjected to different extraction methods, namely short or long agitation, and ultrasound-assisted extractions using different temperatures and distilled water or a 50% (v/v) ethanol as solvents. The extracts were tested for phenolic content (total phenols, ortho-diphenols, and flavonoids), antioxidant capacity (DPPH, 2,2-diphenyl-1 picrylhydrazyl; ABTS, 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid; and FRAP, ferric reducing antioxidant power), and antibacterial activity. The different extraction methods revealed substantial variations (p < 0.05) in phenolic composition and antioxidant capacity. The highest phenolic content and antioxidant capacity were achieved using 24 h extraction, agitation, 50 °C, and ethanol as the solvent. Furthermore, the extracted compounds displayed antibacterial activity in specific tested bacterial strains. This study highlights the nutraceutical potential of L. edodes' SMS, positioning it as a valuable dietary supplement for animal nutrition, with emphasis on its prebiotic properties. Hence, this research unveils the promising health benefits of SMS in both human and animal nutrition.

Effects of Dietary Incorporation of Grape Stalks Untreated and Fungi-Treated in Growing Rabbits: A Preliminary Study.

This study aimed to evaluate the effect of the incorporation of untreated grape stalks (UGS) and fungi-treated grape stalks (Lentinula edodes, TGS) in rabbits' diets. The control group was fed with a control diet without grape stalks (C), two experimental groups were fed on diets with 5% and 10% incorporation of UGS (5UGS and 10UGS), and two with 5% and 10% incorporation of TGS (5TGS and 10TGS). Rabbits fed with TGS diets showed higher daily weight gain (p = 0.034), feed conversion rate (p = 0.002), carcass weight (p = 0.038), and reference carcass weight (p = 0.03) when compared to the control diet. Moreover, animals fed with TGS diets showed an increase in the caecum (p = 0.015) and small intestine (p = 0.021) lengths and in the total volatile fatty acid content (p = 0.005) compared to animals fed UGS diets. Blood triglyceride levels were lower in animals fed with TGS diets compared to UGS (p = 0.005) and C (p ≤ 0.001) diets (12% and 19% lower, respectively), and a trend to lower cholesterol levels was observed (p = 0.071). Meat from rabbits fed with TGS diets had higher levels of linoleic acid, γ-linolenic, ∑ω-6, ∑PUFA, and ∑PUFA/∑SFA ratio compared to rabbits fed with the C diet. Results indicated that grape stalks (UGS and TGS) could be effectively used as an alternative raw material in rabbits' diets without compromising animal performance.