208 SUPEROVULATORY RESPONSE AND EMBRYO PRODUCTION IN HOLSTEIN COWS FED DIETS ENRICHED IN OLEIC, LINOLEIC, OR α-LINOLENIC ACID

Abstract

Early embryonic development is enhanced in Holstein cows fed diets enriched in linoleic and α-linolenic acids compared to those fed a diet enriched in stearic fatty acid (Thangavelu et al. 2007; Theriogenology 68, 949–957). A positive effect of oleic acid on oocyte competence in vitro has been reported (Aardema et al. 2011; Biol. Reprod. 85, 62–69), but the influence of oleic acid on early embryonic development has not been investigated. Therefore, our objective was to evaluate the effects of diets enriched in oleic, linoleic, or α-linolenic acid on superovulatory response and embryo production. Non-lactating Holstein cows were blocked by parity and bodyweight, and assigned to one of three diets supplemented with canola (CAN, n = 8; 62% oleic acid), sunflower (SUN, n = 7; 73% linoleic acid), or flax (FLX, n = 8; 57% α-linolenic acid). Cows were individually offered hay (9.4 kg) and concentrate mixture (4.1 kg) supplemented with one of the three rolled oilseeds (~8% of dietary dry matter). After a minimum of 21 days of diet adaptation, cows were given FSH (300 mg total dose, eight 12-hourly injections), artificially inseminated twice, 12 h apart, with semen of the same sire and ova/embryos recovered non-surgically 7.5 days post-insemination. Once started on a diet, cows continued to receive the same diet until the end of the experiment. Thirty-five collections (flushing) were performed (CAN: 12, SUN: 11 and FLX: 12) and data were analysed using the GENMOD procedure of SAS (SAS Institute Inc., Cary, NC, USA); results are presented as mean ± s.e. Number of corpora lutea (12.8 ± 2.6, 14.5 ± 1.2 and 13.1 ± 1.5), anovulated follicles (3.0 ± 1.4, 2.0 ± 1.1 and 2.6 ± 0.9), and total ova/embryos (7.5 ± 2.0, 8.6 ± 1.7 and 7.3 ± 1.2) did not differ (P > 0.05) for CAN, SUN, and FLX treatment, respectively. Cows fed SUN tended (P = 0.06) to produce more transferable embryos (6.1 ± 1.7) than those fed CAN (4.3 ± 1.5), but did not differ from those fed FLX (4.8 ± 1.3). There were fewer (P < 0.05) unfertilized ova in cows fed SUN (0.6 ± 0.5) than in those fed either CAN (1.3 ± 0.6) or FLX (1.8 ± 0.9). Conversely, cows fed FLX had fewer (P < 0.05) degenerated embryos (0.7 ± 0.4) compared to those fed either CAN (1.9 ± 0.6) or SUN (1.9 ± 0.5). The number of expanded blastocysts was greater (P < 0.05) in cows fed CAN (1.08 ± 0.57) than in those fed FLX (0.25 ± 0.25), but it was not different from those fed SUN (0.90 ± 0.36). In summary, the type of dietary fatty acid did not affect superovulatory response, but a diet enriched in oleic acid resulted in more expanded blastocysts, whereas a diet enriched in linoleic acid significantly reduced the number of unfertilized ova and numerically increased transferable embryos. The diet enriched in α-linolenic acid resulted in fewer degenerated embryos. This study was supported by Alberta Meat and Livestock Agency, Alberta Milk, and Alberta Innovates-BioSolutions.