This study was conducted in dairy sheep to test the hypothesis that the milk concentration of antilipogenic fatty acids (FA) may account for individual variations in marine lipid-induced milk fat depression (MFD). We used fifteen ewes receiving 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]. Milk production and composition, and milk FA profile were recorded for 3 consecutive days before and after (i.e., days 31, 32 and 33) treatments. Milk production was not affected by the diets (P>0.10) but milk fat concentration was decreased up to 25.4% in RESPO+ and 7.6% in RESPO- (P<0.0001). Consumption of the fish oil diet enhanced (P<0.01) milk content of both potentially healthy FA (e.g., cis-9 trans-11 CLA, α-linolenic acid, very long chain n-3 FA and total PUFA) and antilipogenic FA (e.g., cis-9 16:1, trans-10 and cis-11 18:1, trans-10 cis-15 18:2, trans-9 cis-11 and trans-10 cis-12 CLA, and 10-oxo-18:0). However, differences were hardly detected between RESPO- and RESPO+, which obliges to reject the hypothesis.

Este trabajo forma parte del Proy. AGL2014-54587; L. Rodríguez-López disfruta de una beca predoctoral FPI y P.G. Toral de un contrato Ramón y Cajal, todos ellos del MINECO y con cofinanciación del FSE.

3 páginas, 2 tablas.-- Trabajo presentado a las XVII Jornadas sobre Producción Animal AIDA (Zaragoza, 30 y 31 de mayo, 2017).

Peer reviewed