337. DIETARY OMEGA-3 FATTY ACID SUPPLEMENTATION ALTERS EMBRYO DEVELOPMENT AND METABOLISM IN SOWS

The long-chain omega-3 polyunsaturated fatty acids (LCPUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have diverse biological effects, including the improvement of cardiovascular health and asthma. The aim of this study was to examine how dietary LCPUFA supplementation of sows influenced follicular dynamics, embryo development and metabolism. A total of 30 sows per treatment were fed a control diet (CD: standard commercial ration) or an omega-3 supplemented diet (O-3: diet formulated with 3 g fish oil/kg) for 6 weeks. Ovaries were collected at slaughter and weighed 3–5 days post-weaning. Oocytes were aspirated and counted from 3 different follicle size groups (1–4mm, 4–8mm and 8+ mm) and matured in vitro for 44–46 h, prior to (a) fertilization using IVF and analysis of subsequent embryo development in culture, (b) assessment of embryo respiration rate (EmbryoScope technology, UniSense, Denmark) and glucose metabolism (radiolabelled glucose technique). Granulosa cells collected at aspiration were analysed for gene expression using q-PCR. Despite no effect of O-3 supplementation on ovary weight nor the proportion of oocytes that were fertilised and cleaved, there tended to be more medium and large follicles for the O-3 fed group. Significantly more embryos from sows fed O-3 diets developed to blastocyst stage (P < 0.05) and these tended to have an increased number of cells (P = 0.06). At the zygote stage, diet didn’t influence embryo respiration rate but glucose utilisation by blastocysts was significantly lower for O-3 treatment compared to CD (P < 0.006). Gene expression of the ER2-α, FSH-receptor, or the prostaglandin receptors EP2 and EP4 did not differ, but there tended to be reduced expression of progesterone receptor (PR) and cycloxygenase-2 (COX-2) in granulosa cells from O-3 sows (P < 0.07). In summary, O-3 dietary supplementation changed follicular growth, embryo development and blastocyst metabolism. Further studies are ongoing to determine the effect of supplementation on embryo survival and litter size.