Effect of hazelnut skin by-product supplementation in lambs' diets: Implications on plasma and muscle proteomes and first insights on the underlying mechanisms

This study aimed to evaluate the effect of hazelnut skin by-product supplementation on lamb meat quality characteristics and plasma and muscle proteomes. Twenty-two Valle del Belice male lambs were divided into two experimental groups: control (C), fed a maize-barley diet and hazelnut (H), fed hazelnut skin by-product as maize partial replacer in the concentrate diet. The meat of lambs fed hazelnut skin showed greater values of lightness, redness, yellowness, and chroma color parameters together with the highest myofibril fragmentation index. Two-dimensional electrophoresis and mass spectrometry applied on plasma proteome identified 20 protein spots corresponding to 18 unique gene names to be differently expressed due to hazelnut skin by-product substitution. For the early post-mortem muscle, 23 protein spots (42 unique gene names) were significantly up-regulated due to hazelnut skin by-product supplementation. Four proteins these being APOA1, PHB, ACTG1 and ALB, were found to be common to the two proteomes suggesting that these proteins could be candidate biomarkers to monitor in vita and post-mortem lamb meat quality traits. This study evidenced the main mechanisms involved in the supplementation of hazelnut skin by-product in lambs' diet and confirmed the possibility of using plasma proteome as a non-invasive way to predict lamb meat quality.