Fatty Acid Profile, Oxidative Stability, and Quality Traits of Meat from Broilers Fed Raw or Fermented Rapeseed Cake

Raw rapeseed cake represents a viable alternative protein source for broiler diets, and its fermentation may reduce anti-nutritional factors while improving its feeding value. This 35-day study involved 300 one-day-old ROSS 308 chicks (three groups, four replicates/group, with 25 broilers/replicate) raised on wood shavings (16 broilers/m²). Broilers received either a control diet (corn-soybean meal) or diets supplemented with 200 g/kg of RRCs (raw rapeseed cakes) or fermented rapeseed cakes (FRCs). At the end of the trial, eight broilers per group were slaughtered, and breast and thigh samples were collected. The nutritional quality of the meat was assessed by proximate composition, fatty acid profile, and health-related lipid indices. In addition, oxidative status during shelf-life storage was evaluated based on myoglobin content (Mb), metmyoglobin concentration (metMb), total antioxidant capacity (TAC), and lipid peroxidation, determined as thiobarbituric acid reactive substances (TBARS). The omega-3 fatty acid content in fresh breast and thigh samples was significantly higher in RRC and FRC groups compared to C (p = 0.014; p = 0.0001), which significantly decreased the omega-6/omega-3 ratio for both samples (p = 0.0001). The TBARS values exhibited a significant decrease (p < 0.0001) between groups for breast and thigh samples. The TAC values showed significantly higher antioxidant capacity in RRC and FRC breasts and thigh samples compared to C, considering both group differences (p < 0.0001) and shelf-life evaluation (p = 0.001). In thigh samples, the RRC group showed lower metMB values compared to the control group (p = 0.042), whereas differences in breast samples were not statistically significant (p = 0.054). Healthy lipid indexes registered significantly lower values for experimental groups, both for breast and thigh, and for linoleic/α-linolenic acid ratio (p = 0.0001), but for atherogenicity index (AI) (p = 0.0001) and thrombogenic index (TI) (p = 0.0001) only for the RRC group, while nutritive value index (NVI) significantly increased (p = 0.0001) on both groups. In conclusion, RRC and FRC may represent sustainable alternatives to soybean meal in broiler nutrition, supporting improvements in meat lipid profile and oxidative stability. Overall, the RRC group showed more significant effects on n-3 fatty acid enrichment and lipid quality indices, whereas the FRC mainly influenced proximate composition and selected color parameters.