Dietary omega-3 and -6 polyunsaturated fatty acids affect the composition and development of sheep granulosa cells, oocytes and embryos.
The evidence that omega-3 (n-3) and -6 (n-6) polyunsaturated fatty acids (PUFAs) have differential effects on ovarian function, oocytes and embryo quality is inconsistent. We report on the effects of n-3 versus n-6 PUFA-enriched diets fed to 36 ewes over a 6-week period, prior to ovarian stimulation and follicular aspiration, on ovarian steroidogenic parameters and embryo quality. Follicle number and size were unaltered by diet, but follicular-fluid progesterone concentrations were greater in n-3 PUFA-fed ewes than in n-6 PUFA-fed ewes. The percentage of saturated FAs (mostly stearic acid) was greater in oocytes than in either granulosa cells or plasma, indicating selective uptake and/or de novo synthesis of saturated FAs at the expense of PUFAs by oocytes. High-density lipoproteins (HDLs) fractionated from sera of these ewes increased granulosa cell proliferation and steroidogenesis relative to the FA-free BSA control during culture, but there was no differential effect of n-3 and n-6 PUFAs on either oestradiol or progesterone production. HDL was ineffective in delivering FAs to embryos during culture, although n-6 PUFA HDL reduced embryo development. All blastocysts, irrespective of the treatment, contained high levels of unsaturated FAs, in particular linoleic acid. Transcripts for HDL and low-density lipoprotein (LDL) receptors (SCARB1 and LDLR) and stearoyl-CoA desaturase (SCD) are reported in sheep embryos. HDL reduced the expression of transcripts for LDLR and SCD relative to the BSA control. The data support a differential effect of n-3 and n-6 PUFAs on ovarian steroidogenesis and pre-implantation development, the latter in the absence of a net uptake of FAs.
School of Biosciences School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, UK.
K E
KE
Wonnacott
W Y
WY
Kwong
J
J
Hughes
A M
AM
Salter
R G
RG
Lea
P C
PC
Garnsworthy
K D
KD
Sinclair
D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000378:metabolism; D004622:Embryo, Mammalian / Q000378:metabolism*; D047108:Embryonic Development; D005227:Fatty Acids / Q000097:blood / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism / Q000502:physiology; D043371:Fatty Acids, Omega-6 / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism / Q000502:physiology; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000737:chemistry; D015571:Follicular Fluid / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D012739:Gonadal Steroid Hormones / Q000097:blood / Q000378:metabolism / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008074:Lipoproteins / Q000008:administration & dosage / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism / Q000502:physiology*; D010053:Ovary / Q000033:anatomy & histology / Q000187:drug effects; D010062:Ovulation Induction; D010938:Plant Oils / Q000008:administration & dosage / Q000737:chemistry; D011897:Random Allocation; D034561:Sheep, Domestic; D000074242:Sunflower Oil
D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005395:Fish Oils; D012739:Gonadal Steroid Hormones; D008074:Lipoproteins; D010938:Plant Oils; D000074242:Sunflower Oil; C030341:salmon oil; D002784:Cholesterol