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.