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

Simple Summary

The use of winery by-products as an animal feed ingredient in rabbit production can enhance the sustainability of this livestock sector by reducing feeding costs and simultaneously diminishing environmental problems related to the management of those by-products. White-rot fungi have been studied for the delignification of lignocellulosic materials due to their potential to decrease the content of lignin. In fact, white-rot fungi also improve the nutritional value due to the deposition of bioactive compounds, acting as a possible biological treatment to enhance the nutritive value of grape stalks. The objective of this work was to evaluate the incorporation of untreated grape stalks and fungi-treated grape stalks in rabbits’ diets.

Abstract

This study aimed to evaluate the effect of the incorporation of untreated grape stalks (U_GS) and fungi-treated grape stalks (Lentinula edodes, T_GS) 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 U_GS (5U_GS and 10U_GS), and two with 5% and 10% incorporation of T_GS (5T_GS and 10T_GS). Rabbits fed with T_GS 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 T_GS 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 U_GS diets. Blood triglyceride levels were lower in animals fed with T_GS diets compared to U_GS (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 T_GS 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 (U_GS and T_GS) could be effectively used as an alternative raw material in rabbits’ diets without compromising animal performance.

Optimized Pitfall Trap Design for Collecting Terrestrial Insects (Arthropoda: Insecta) in Biodiversity Studies

Pitfall traps are commonly used for the collection of terrestrial insects in ecology and biology studies; they are relatively straightforward to manufacture and there is a large variety of models described in the literature. However, they present a few drawbacks: (i) the removal and transport of the collected material are not practical; (ii) they have low resistance and durability; (iii) they fail to correctly protect the attractive bait against adverse weather conditions and scavengers, and (iv) evaporation of the liquid used inside the trap. We proposed an optimized pitfall trap design for terrestrial insect collection made from cheap and easily accessible materials. The new design allows the transfer of the collected material to the lab by removing only that part of the trap where the insects have been captured; the other part remains in its original place. Thus, the proposed trap allows easier operation since there is no need to transport water to replenish the traps after each transfer; in addition, there is less volume and weight to be carried. The trap can remain in the field for months because of the durability of its material. Furthermore, the collected material is better protected against adverse weather conditions and scavengers. Currently, an efficient and rapid sampling strategy in the field is of global interest to understand mechanisms that can contribute to the monitor changes in phenology, succession, and biodiversity.