title: Effects of dietary unsaturated fatty acids on oocyte quality and follicular development in lactating dairy cows in summer.
abstract: Dietary sources of fatty acids were evaluated for their influence on oocyte quality and follicular development using 54 lactating cows in summer. Fat supplements were 1) sunflower oil (80% cis 18:1), 2) Ca salt of transoctadecenoic acids (57% trans 18:1), 3) Ca salt of vegetable oils (30% 18:2), and 4) linseed oil (56% 18:3 and 16% 18:2). Fats were fed at 1.35% of dietary dry matter beginning at 5 wk prior to expected calving date and at 1.5% (oils) and 1.75% (Ca salts) of dietary dry matter for 15 wk after parturition. Four days following a programmed induced ovulation, 5 transvaginal oocyte aspirations were performed 3 or 4 d apart. Three days after the last aspiration, PGF2alpha was injected, followed 3 d later by a GnRH injection and a timed artificial insemination (d 0) 16 to 20 h later. For the first 4 aspirations, oocytes grading 1 or 2 were used for in vitro embryo production. Total cell number and the proportion of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive blastomeres were analyzed at d 8. At the fifth aspiration, the occurrence of metaphase II, group II caspase activity, and TUNEL labeling were determined after oocyte maturation. A total of 1,011 oocytes were collected. The proportion of oocytes with high caspase activity was greater for grade 3 compared with grades 1 and 2 (37.5 vs. 1.54 and 1.61%). Feeding polyunsaturated fatty acids, as compared with monosaturated fatty acids, failed to affect oocyte quality, as demonstrated by subsequent embryo development. Cows fed 18:2- or 18:3-enriched diets had a larger preovulatory follicle at insemination and subsequent volume of the corpus luteum compared with those fed cis 18:1 or trans 18:1 diets (16.8, 16.2 vs. 15.0, 14.9 +/- 0.7 mm; 7,323, 8,208 vs. 6,033, 5,495 +/- 644 mm3, respectively). The previously documented benefits of polyunsaturated fatty acids on reproductive performance appear to reflect actions at alternative biological windows in lactating dairy cows.
authors.affiliation: Department of Animal Sciences, University of Florida, Gainesville, Florida 32611-0910, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Bilby
authors.forename: J
authors.initials: J
authors.lastname: Block
authors.forename: B C
authors.initials: BC
authors.lastname: do Amaral
authors.forename: O
authors.initials: O
authors.lastname: Sa Filho
authors.forename: F T
authors.initials: FT
authors.lastname: Silvestre
authors.forename: P J
authors.initials: PJ
authors.lastname: Hansen
authors.forename: C R
authors.initials: CR
authors.lastname: Staples
authors.forename: W W
authors.initials: WW
authors.lastname: Thatcher
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002417:Cattle / Q000196:embryology / Q000502:physiology*; D003612:Dairying; D004041:Dietary Fats / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D004622:Embryo, Mammalian / Q000187:drug effects; D004971:Estrus / Q000502:physiology; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D006728:Hormones / Q000097:blood; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007774:Lactation; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D006080:Ovarian Follicle / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D012621:Seasons
chemical_list: D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D006728:Hormones; D007334:Insulin-Like Growth Factor I; D020169:Caspases