In-depth characterization of myofibrillar muscle proteome changes in lambs fed hazelnut skin by-products

This study investigated the effect of hazelnut skin by-products supplementation on lamb myofibrillar proteome changes during post-mortem storage (0, 4, and 7 days). Gel-based proteomics and bioinformatics approaches were applied to reveal the underlying biochemical pathways and their importance in lamb meat texture development. Twenty-two Valle del Belice male lambs were randomly assigned to two dietary treatments: control (C) for lambs fed with maize-barley diet, and hazelnut skin (H) for lambs fed hazelnut skin by-product as maize partial replacer in the concentrate diet (150 g/kg DM basis). A greater myofibrillar fragmentation index (MFI) was found in meat from the C group at day 0 of storage (91.33 vs 98.38 in H and C groups, respectively). Conversely, starting from 4 days of storage, higher MFI values were observed in meat from lambs fed hazelnut skin (113.74 and 116.1 vs 99.28 and 107.26 in H and C groups at 4 and 7 days, respectively). Myofibrillar proteome changes estimated by SDS-PAGE and immunoblotting revealed a degradation of desmin (P<0.01) and troponin T (P<0.001) intact proteins, and an increase in the abundance of the appearing 30 kDa fragment (P<0.001) after 4 days of storage in meat from H than the C group. In-depth proteomics and bioinformatics revealed 44 proteoforms (26 unique proteins), mainly involved in actin filament-based process/cytoskeleton organization, energy metabolism, and heat shock proteins, as the major interconnected pathways impacted by hazelnut by-product feeding strategy on lamb meat quality. Twelve proteins were proposed in this trial as potential biomarkers of lamb meat texture as a consequence of hazelnut skin by-products supplementation.