Lamb Performance and Meat Quality: The Impact of Chromium in High-Concentrate Diets and Its Molecular Effects on Skeletal Muscle During Finishing Phase

Chromium is an essential trace mineral in insulin-mediated glucose metabolism, potentially affecting protein synthesis and improving performance and meat quality. This study aimed to assess the impact of chromium on performance, carcass characteristics, meat quality, and the gene expression in the skeletal muscle of lambs fed a high-concentrate diet. Sixteen just just-weaned Dorper × Santa Inês crossbred lambs, weighing 24.95 ± 1.97 kg, were allocated into a control group, a basal diet without chromium in the diet supplementation (CTL) or chromium supplementation (Cr3.0), with the addition of 3.0 mg of chromium per kg of dry matter (Cr3.0DM). The animals were housed in individual pens and fed a diet comprising 6% forage and 94% concentrate for 60 days. We evaluated average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE), carcass characteristics, meat quality, and muscle transcriptome. Chromium supplementation increased ADG (P = 0.048) and tended to improve FE (P = 0.08). Further, chromium supplementation increased kidney, pelvic, and heart fat (P ≤ 0.05). In meat, a reduction in cooking losses and an increase in shear force were observed in the meat of lambs treated with chromium-treated lambs (P ≤ 0.05). Transcriptome analysis revealed 21 differentially expressed genes, with 9 downregulated genes, including COX6C, TMED5, ODC1, HNRNPA1, and 12 upregulated genes, such as RPL39, RPL35A, RPS25, NSA2, RRM2, GCNT1, associated with pathways of ribosome biogenesis, protein synthesis, collagen remodeling, and fat metabolism. In conclusion, dietary chromium supplementation at 3.0 mg/kg DM can improve performance and efficiency without affecting carcass characteristics. In meat, chromium reduced cooking losses, potentially increasing its juiciness, but reduced its juiciness-related tenderness, negatively impacting the tenderness of the meat.