Incorporation of untreated or white-rot fungi treated cowpea stover on performance, digestibility, health and meat quality of growing rabbits

Effect of Lentinus sajor-caju on the chemical composition and antioxidant activity of highland barley straw under solid-state fermentation

Introduction

The efficient utilization of straw resources as animal feed has gained considerable attention. The objective of this study was to evaluate whether Lentinus sajor-caju treatment alters the chemical composition and antioxidant activity of highland barley straw and enhances its functional value as a ruminant feed.

Methods

The chemical composition, antioxidant capacity, and metabolomic profile of highland barley straw were determined after 21 days of solid-state fermentation with L. sajor-caju at 25°C. The differential metabolites between fermented and unfermented highland barley straw were identified by LC-MS and the relationship between the identified metabolites and antioxidant capacity was elucidated.

Results

The results showed that, compared with untreated highland barley straw, the crude protein and ether extract contents were higher (51.55 and 76.43%, respectively) in highland barley straw after 21 days of incubation with L. sajor-caju, whereas the hemicellulose, cellulose, and acid detergent lignin contents were lower (2.48, 25.08, and 45%, respectively). The total antioxidant capacity was significantly higher in L. sajor-caju-treated than in untreated highland barley straw. In total, 600 differential metabolites (301 upregulated and 299 downregulated) were identified between L. sajor-caju-fermented and unfermented highland barley straw. Correlation analysis results showed that Fe2+ scavenging and total phenolic content were strongly correlated with total antioxidant capacity. Meanwhile, the differential flavonoid metabolites between fermented and unfermented highland barley straw were primarily associated with antioxidant activity, with kaempferol 3-xylosylglucoside, isoginkgetin, and rhoifolin being the most representative.

Conclusion

Thus, this study demonstrates that L. sajor-caju could enhance the functional value of highland barley straw, showing the potential of L. sajor-caju for improving the utilization of agricultural straws in ruminants.

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.