213 MATURATION OF OOCYTES WITH FOLLICULAR FLUID FROM GILTS CONSUMING HIGH FAT AND FRUCTOSE AFFECTS SUBSEQUENT EMBRYO DEVELOPMENT

Abstract

Infertility among women has become a growing issue in the world requiring a significant number to seek treatment by means of assisted reproductive technologies. One suggested reason for the fertility issue, which is known to specifically affect oocyte quality, is the modern diet. Previously, we have demonstrated that feeding a high-fructose diet to gilts led to poor reproductive tract characteristics and infertility. In this study, pre-pubescent gilts were fed either a high-fructose; high-fat diet (HFHF), with 15% beef tallow and 35% fructose; or an industry control diet (IND). Porcine follicular fluid (pFF) collected from these gilts was introduced into in vitro maturation systems to determine whether characteristics of the follicular fluid affect oocyte competence and embryo development. Follicles from ovaries, collected at a local abattoir, were aspirated by an 18 G needle attached to a 10-mL sterile syringe. Then selected cumulus‐oocyte complexes were maturated in vitro in a TCM-199 maturation media with cysteine, glucose, sodium pyruvate, epidermal growth factor (EGF), FSH, LH, and 20% pFF from treatment groups. Additionally, another group of oocytes, labelled follicle fluid free (FFF), were maturated in TCM-199 media without pFF. Three replicate experiments were conducted using a total of 365 oocytes, 124 FFF, 121 IND, and 120 HFHF. Oocytes were denuded by exposure to 0.1% hyaluronidase and oocytes that reached metaphase II (MII) were selected for in vitro fertilisation. After 5 h of co-incubation in modified Tween medium B with milk powder (mTBM)-based IVF media, presumable zygotes were transferred to porcine zygote medium-3 (PZM-3). Blastocyst frequency was recorded on Days 5 and 6. Day 6 blastocysts were stained with Hoechst for total cell number evaluation. The frequencies of blastocyst formation among the treatment groups were compared by a chi-squared test, and total cell numbers were compared by Student's t-test. Statistical significance was defined by P < 0.05. The frequency of oocytes reaching metaphase II (MII) were observed as 77.4% FFF, 72.7% IND, and 71.7% HFHF (P > 0.05), indicating the supplementation of pFF did not affect maturation. Day 5 blastocysts were observed at frequencies of 8.3% FFF, 6.8% IND, and 4.7% HFHF and did not differ. However, frequency of Day 6 blastocysts from HFHF group was tended to be lower compared with that of other groups; 12.5% FFF, 11.4% IND, and 4.7% HFHF (P = 0.06 and P = 0.1). Average total cell number of Day 6 blastocysts observed were 41.0 ± 9.1 FFF, 36.0 ± 8.9 IND, and 48.3 ± 10.6 HFHF. The total cell number from HFHF group tended to be higher than only that of IND group (P = 0.07). Based on these results, we concluded that the follicular fluid of females consuming HFHF diets did not have impact on nuclear maturation of oocytes but might affect oocyte competency, thus resulting in detrimental effects on subsequent development of embryos, especially blastocyst formation. Further studies will help us identify more specific effects of nutrition on oogenesis and subsequent embryo development.