Active ingredients from oil by-products modulate spleen inflammatory and antioxidant response in pigs

Grape seed cakes (GSC) resulted from grape seed oil extraction represent a by-product rich in bioactive compounds such as polyphenols, polyunsaturated fatty acids, fibres, minerals, vitamins etc known for their beneficial anti-inflammatory, anti-microbial, anti-oxidative and immune-modulatory effects. In the present study, we have investigated the effects of dietary grape seed cakes bioactive compounds on several anti-inflammatory and antioxidative biomarkers in spleen of pigs during fattening phase. Twelve crossbred TOPIG hybrid fattening pigs were allocated to two experimental treatments: 1) commercial diet (control group) and 2) a diet including 5% grape seed cakes (GSC group) for 24 days. At the end of experimental period (day 24) pigs were sacrificed and spleen samples were collected and stored at –80°C until analysis. The results showed that GSC diet lowered the gene expression as well as the protein concentration of pro-inflammatory markers: interleukin 1 beta (IL-1β, -52.66%, p<0.05) and interferon gamma (IFN-γ, -42.13%, p<0.05) and had a tendency to decrease that of interleukin 6 (IL-6, -13.25%), tumour necrosis factor alpha (TNF-α, -9.06%) and interleukin 8 (IL-8, -11.08%) when compared to control diet confirming the anti-inflammatory properties of GSC’s active ingredients. The total splenic antioxidant capacity (TEAC) and gene expression of antioxidant enzymes (catalase-CAT and glutathione peroxidase-GPx) were higher in spleen of pigs fed GSC diet than in control group suggesting also the antioxidative potential of GSC. The results related to the molecular mechanism showed a higher expression of gene encoding for PPAR-γ and for Nrf2 in spleen of pigs receiving the GSC diet (Fc 1.81 and 1.58) suggesting that the anti-inflammatory and antioxidant effect of this diet is probably exerted by PPAR-γ and Nrf2 pathway. Further, other percent of dietary GSC inclusion need to be investigated in order to obtain a more complex response related to biomarkers which characterise the fattening/obesity process.