Physicochemical composition, fatty acid profile and sensory attributes of the meat of young Nellore bulls fed sunflower cake from the biodiesel industry

The use of agroindustrial waste to feed ruminants can change the microbial ecology of the animal, affect the fatty acid biohydrogenation extent and improve the profile of fatty acid of tissues. This study was conducted to determine the amount of sunflower cake in the diet of bulls that had the best effects on the physicochemical characteristics, fatty acid composition and sensory attributes of meat. To do so thirty-two intact Nellore bulls with an initial average body weight of 374 +/- 42.5 kg that were used 24 months of age in a design completely randomized (four treatments). Animals were fed 400 g/kg Tifton 85 hay and 600 g/kg concentrate. The inclusion levels of sunflower cake (0, 9, 18, and 27% in DM basis) were the experimental treatments. Sunflower cake inclusion in the diet linearly increased the following characters (P <0.05): total lipid, protein, and cholesterol contents of meat; water-holding capacity; concentration of C18:0, C18:2n-6, Sigma PUPA, Sigma n-6, and Sigma n-6:Sigma n-3 ratios; the h:H index; and the elongase enzymatic activity in the longissimus muscle of the bulls. However, the Warner-Bratzler shear force (WBSF), ash content, Sigma UFA, Sigma MUFA, Sigma UFA:Sigma SFA ratio and Delta 9-desaturaseC16 enzymatic activity in the longissimus muscle of bulls showed a linear reduction (P < 0.05) due to sunflower cake inclusion. A positive quadratic effect was observed for C18:2cis-9trans-11 (CLA) fatty acid, and a negative quadratic effect was observed for in the C18:3n-3. The level of inclusion of sunflower cake reduced the taster evaluation scores of the sensorial attributes regarding flavor, tenderness and overall acceptance compared to the control treatment (0%). Sunflower cake up to 21% of total DM could be fed to decrease feed costs without a major change in the fatty acid profile. However, the slight reduction in the sensory attributes and the increase in the most desirable fatty acids for health should be considered.