The Effects of Supplementing Increasing Doses of EPA and DHA Fatty Acids to Ewes in Late Gestation on Ewe Performance and Milk Production and Offspring Performance and Plasma Metabolites

Multiple studies have shown improvements in performance of livestock due to supplementation of polyunsaturated fatty acids (PUFA). Other studies have shown an effect of fetal programming on offspring in livestock, though little work in this area has been done with ruminants. This research was conducted to evaluate the performance effect of ewes and their lambs when the ewes were supplemented with increasing concentrations of the PUFA docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) as Ca salts during the last 50 d of gestation. The PUFA were supplemented at concentrations of 0%, 1% and 2% to the gestating ewes. Ewes (n=24 per treatment) started receiving the supplements 50 d prior (d -50) to expected lambing (d 1). Supplementation finished on lambing day and all ewes received the same diet after lambing. Ewes were weighed and BCS at d -50, d -20, d 15 and d 60 (weaning). On d 15 milk production and composition was evaluated after 3 hours of separation of the lamb from the ewe. Lambs were bled (to measure plasma concentration of glucose, and NEFA) and weighed on d 1 d 15 and d 60. Data was analyzed using a mixed model of SAS, using a linear and quadratic polynomial contrast for mean separation. There was a quadratic linear effect (P=0.01) for BW. Ewes supplemented with 1% PUFA were heavier than ewes supplemented with 0 or 2% (94.8 vs 91.0 and 89.8 ± 1.06, respectively). There were no difference in BCS, milk production, fat or protein concentration, but there was a trend for increased (linear P=0.06) lactose concentration. There was no difference in lamb BW, or plasma glucose and NEFA concentrations (P>0.1). However, there was a time by treatment interaction on ADG (P <0.05). Lambs of ewes supplemented with PUFA at 1% showed a higher ADG (0.36 kg/d) than the 0% (0.31 kg/d) or 2% (0.33 kg/d) supplementation from birth to d 15. The ADG from d 15 to d 60 was similar for the three treatments. This suggests that the supplementation of EPA and DHA during gestation affects ewe and lamb growth, and these effects may be dose dependent. The fact that the 1% EPA and DHA supplement showed a heavier BW for the ewes and the highest ADG for the lambs without affecting in the same manner MY or composition arises more questions to be answered on the biological effects of PUFA.