La aplicación de la resonancia magnética nuclear de protones (H-NMR) en ovejas con depresión de la grasa láctea: ¿Puede el perfil metabolómico de la sangre explicar la variación individual?

Abstract

This study was conducted in dairy sheep to test the hypothesis that differences in the blood metabolomic profile would explain individual variations in terms of milk fat depression (MFD) when marine lipids were added to the diet. Assaf ewes (n=15) received a total mixed ration supplemented with 0 (control; n=5) or 20 g of fish-oil/kg DM [n=10; with animals divided in those showing a strong (RESPO+, n=5) or slight (RESPO-) MFD]. H-NMR was evaluated in blood samples collected on days 0 and 36. Supplementation with fish oil reduced the concentrations of proline, valine, isoleucine, keratin, lactate and β-glucose in blood. The reductions in amino acid concentrations are in accordance with lower mammary protein synthesis in supplemented ewes. On the other hand, some fatty acids (FA) increased, including some potentially antilipogenic FA that are supposed to be able to induce MFD. However, there was no clear separation between RESPO+ and RESPO-. At the systemic level, blood metabolomic profile was not successful to explain the individual variation in MFD.