http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Dietary fat intake, metabolic hormone secretion, and ovarian physiological function in cows
The hypothesis that the type of dietary fatty acid consumed by the cow differentially affects both luteal and follicular function through altered synthesis of lipoprotein-cholesterol and secretion of metabolic hormones was tested in 2 experiments. In experiment 1, estrous cycling cows were randomly assigned to either a control or a fat-supplemented diet consisting of animal tallow, soybean oil, or fish oil. After 20 days of consumption, estrus was induced and ovarian follicular populations were monitored via transrectal ultrasound. Fluid from a large follicle was aspirated between days 10 and 14 of the cycle. Cows were ovariectomized between days 11-13 of the subsequent cycle. After 20 days of consumption in experiment 2, ovarian follicular populations were monitored for 4 days followed by aspiration of the dominant follicle. Heifers were then superovulated with FSH-P$ sp circler.$ All fat-supplemented diets increased (P $<$ 0.07) serum and follicular fluid concentration of cholesterol and progesterone, and serum concentration of growth hormone in both experiments. In experiment 1, animal tallow and fish oil diets tended to produce an increase (P $<$ 0.10) in concentrations of serum insulin and follicular fluid IGF-I, and in the number of medium-sized follicles at ovariectomy (day 50). However, the soybean oil diet maximized (P $<$ 0.05) these effects, and produced an abrupt $( approx$ day 20) increase (P $<$ 0.07) in serum concentration of insulin and the number of medium-sized follicles in both experiments. Increased (P $<$ 0.04) follicular fluid concentration of androstenedione in large estrogen inactive follicles paralleled hyperinsulinism in the Soybean Oil group in experiment 1. Conversely, the animal tallow diet produced an increase (P $<$ 0.02) in concentrations of estradiol in these follicles relative to the Soybean Oil and Control groups. Concentration of inhibin in medium-sized follicles was increased (P $<$ 0.05) in the Animal Tallow and Fish Oil groups at ovariectomy in experiment 1. All supplemental fats were cholesterologenic and capable of increasing serum concentrations of progesterone and growth hormone. They were also insulinogenic and folliculogenic over the long-term. However, soybean oil (rich in C18:2) maximized these effects within 20 days. Dietary fats differentially enhance ovarian follicular recruitment and steroidogenesis through differences in their fatty acid constituents and metabolic sequelae.
"Major subject: Physiology of Reproduction."