Effects of gestational n-3 and n-6 fatty acid supplementation on ewe and lamb performance

This study aimed to evaluate the effects of omega (n) -3, n-6, or n-3 + 6 supplementation during gestation on ewe performance, lamb growth, and performance of ram lambs. Eighty-three Targhee ewes (initial body weight [BW] = 69.0 ± 1.5 kg; body condition score [BCS] = 3.1 ± 0.04) were selected and assigned to the experiment at the beginning of the breeding season. Ewes were ranked by age, BW, and BCS, allocated to 24 drylot pens, and received one of four treatments (as fed basis): 1) 22 g/ewe daily of Ca salts of saturated (SFA) and monosaturated fatty acids (MUFA) based on palmitic and oleic acids (CON; EnerGII, Virtus Nutrition, LLC, Corcoran, CA; n = 6); 2) 22 g/ewe daily of Ca salts of PUFA based on eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (n-3, Strata; Virtus Nutrition, LLC; n = 6); 3) 22 g/ewe daily of Ca salts of PUFA based on linoleic acid (n-6, Prequel; Virtus Nutrition LLC; n = 6); or 4) 11 g/ewe of Ca salts of PUFA EPA+DHA (Strata) and 11 g/ewe of Ca salts of PUFA linoleic acid (Prequel) daily (n-3 + 6; n = 6). Fatty acid supplementation occurred from d 0 until 88 of the study. Ewe BW and BCS were recorded at d -8, 51, 93, and 240. Twenty-four hours after birth, the lamb's sex and BW were recorded, and a blood sample was collected. Body weight, BCS, and scrotal circumference (SC) were collected on all ram lambs at d 352, 380, and 408. No differences were observed in ewe BW or BCS at d -8, 51, or 93 (P ≥ 0.26) between the treatment groups. A treatment × day interaction was observed (P = 0.02) for ewe BCS, where only on d 240, ewes fed n-6 had an increase in BCS vs. the n-3, n-3 + 6, and CON groups (P = 0.03). A treatment × day interaction was observed for circulating linoleic, EPA, and total n-6 PUFA (P ≤ 0.02). On d 51 and d 93, linoleic acid and total n-6 were greater in n-6 and intermediate in n-3 + 6 vs. CON and n-3 (P ≤ 0.02). Plasma EPA was similar at baseline (P ≥ 0.55) but increased on d 51 and d 93 in n-3 and n-3 + 6 compared with n-6 and CON (P ≤ 0.05). No differences in lamb performance were detected between treatment groups (P ≥ 0.25). No differences were detected (P ≥ 0.31) in ram lamb BW, BCS, or SC. Overall, maternal supplementation with n-3 and/or n-6 fatty acids during the gestational period evaluated herein effectively altered maternal and placental PUFA profiles but did not improve lamb growth to weaning or postweaning development of rams.