030 Effects of Dietary Omega-3 Fatty Acids on Growth and Reproduction in Gilts Farrowed By Sows Fed Diets Rich in Omega-3 Fatty Acids.

The objective of this experiment was to determine the effects of menhaden oil (MO), a rich source of omega-3 fatty acids, on growth and puberty onset in gilts farrowed by sows fed diets also containing MO. Yorkshire × Landrace sows (n = 44) received: 1) control gestation and lactation diets, or 2) diets that included 4% MO (Virginia prime; Omega Protein, Inc., Houston, TX). Control and MO diets were isocaloric and isolysinic. At weaning, 84 gilts farrowed by control or MO sows were placed in pens of three gilts each and provided ad libitum nursery and then grow-finish control or 4% MO diets. After grow-finish, gilts received daily boar exposure and were sacrificed 8 to 11 d after puberty onset for reproductive tract evaluation. Nursery, grow-finish and overall ADG, ADFI and Feed:Gain (F:G) were similar (P > 0.21) for gilts farrowed by control or MO sows. Nursery, grow-finish, and overall ADG were also similar (P > 0.24) for gilts fed control or MO diets. Compared to controls, however, gilts fed MO diets tended to consume less feed in the nursery (1.18 ± 0.08 vs. 0.98 ± 0.08 kg; P = 0.09) and overall (1.83 ± 0.04 vs. 1.72 ± 0.04 kg; P = 0.06). Thus, overall F:G was greater (2.52 ± 0.03 vs. 2.33 ± 0.03; P < 0.01), and nursery (2.12 ± 0.04 vs. 1.80 ± 0.14; P = 0.10) and grow-finish (3.07 ± 0.19 vs. 2.58 ± 0.19; P = 0.08) F:G tended to be greater, for control compared with MO gilts. Age at puberty was greater (P = 0.02) for gilts farrowed by MO sows (205.1 ± 3.2 d) compared to gilts farrowed by controls (193.9 ± 3.2 d). Age at puberty tended to be greater (P = 0.09), however, for control gilts (203.5 ± 3.2 d) compared to gilts fed MO (195.5 ± 3.2 d). Ovulation rate was greater (P = 0.03) for gilts farrowed by controls (14.9 ± 0.7) compared to gilts farrowed by MO sows (12.6 ± 0.7). In summary, feeding gilts MO diets enhanced feed conversion efficiency and hastened puberty onset. In contrast, puberty was delayed and ovulation rate decreased in gilts farrowed by sows that consumed MO during gestation and lactation.