Patterns of plasma LH, FSH, oestradiol and corticosteroids from birth to the first oestrous cycle in Meishan gilts

Prunier, Armelle; Chopineau, M.; Mounier, Anne-Marie; Mormède, Pierre

doi:10.1530/jrf.0.0980313

Cited by 31 publications

(36 citation statements)

References 18 publications

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“…A high level of atretic follicles 1-5 mm in diameter is the indicator of follicular selection process. The stage achieved by large, selected follicles does not prevent them from atresia; however, the intensity of that process in follicles with a diameter > 6 mm is much weaker (Prunier et al, 1993).…”

Section: Folliculogenesis In Prepuberal Giltsmentioning

confidence: 95%

“…The above-mentioned pulsatile LH secretion enables further follicular development despite the low basic level of this hormone. The decreasing FSH concentration causes atretic changes in follicles that did not synthesise LH receptors (Hunter and Wiesak, 1990;Prunier et al, 1993). The indicator of follicular maturity is activation of the enzymatic aromatase complex in the granulosa cells, which enables the synthesis and secretion of oestradiol and inhibin (Yen et al, 2005).…”

Section: Acta Veterinaria Hungarica 56 2008mentioning

confidence: 99%

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Physiological mechanisms of ovarian follicular growth in pigs — A review

Schwarz

Kopyra

Nowicki

2008

Acta Veterinaria Hungarica

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Follicular growth after antrum formation is determined by folliclestimulating hormone (FSH). Only two ways are possible for recruited follicles, continuing development or atresia. In gilts, intensive ovarian follicular growth begins between 60 and 100 days of age, and fluctuations of the ovarian morphological status last about 20 days; however, at that time there are no really large follicles. Final follicular development is under luteinising hormone (LH) control; this is why the attainment of puberty is related to an increase in serum oestradiol to a level that causes a preovulatory surge of this gonadotropin. The pool of follicles at the beginning of the oestrous cycle is about 30-40, most of which are small (< 3 mm) and growing. Then, the pool of follicles increases to about 80 in the mid-luteal phase but about 50 of them are small and 30 are medium sized (3-6.9 mm). Some of these follicles are in the growing phase, but some are atretic. Between days 7 and 15 of the oestrous cycle the percentage of atretic follicles fluctuates between 12 and 73%. At that time there are no large (> 7 mm) follicles because of the suppressing effect of progesterone. The number of small follicles declines after luteolysis. From the pool of medium follicles, large follicles are selected under the influence of LH, but about 70% of the medium-sized follicles become atretic. Because of the long-lasting selection process there is a significant heterogeneity in the diameter of large follicles in oestrus. However, the number of follicles correlates with the number of corpora lutea after ovulation. Individual follicular development and the relationship between follicles are still poorly known. The use of ultrasonography may give a closer insight into these phenomena.

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Section: Folliculogenesis In Prepuberal Giltsmentioning

confidence: 95%

Section: Acta Veterinaria Hungarica 56 2008mentioning

confidence: 99%

Physiological mechanisms of ovarian follicular growth in pigs — A review

Schwarz

Kopyra

Nowicki

2008

Acta Veterinaria Hungarica

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“…Profiles of LH were analyzed as previously described [23]. Characteristics of LH secretion (mean and basal concentrations, number of pulses) were calculated and used for statistical analyses.…”

Section: Calculations and Statistical Analysesmentioning

confidence: 99%

Dietary protein restriction during lactation in primiparous sows with different live weights at farrowing: II. Consequences on reproductive performance and interactions with metabolic status

et al. 2005

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-The hypothesis that the restriction of dietary protein during lactation has different impacts on reproductive performance in light and heavy sows at farrowing was investigated, as well as the relationships between reproductive parameters and sow metabolic data. At farrowing, 38 primiparous sows were assigned to one of three groups: sows weighing 180 kg not restricted in dietary protein during lactation (180CP); sows weighing 180 or 240 kg restricted in protein (180LP and 240LP). Twenty-four sows were catheterized and serial blood samples were collected 1 d before and 1 d after weaning. The sows were inseminated at the first estrus after weaning and slaughtered at d 30 of gestation. Protein restriction reduced the proportion of sows that returned to estrus within 8 d after weaning in the 180LP sows (P < 0.03), but not in the 240LP sows. It also induced a reduction in ovulation rate in the 180LP sows (P < 0.05) and, to a lesser extent, in the 240LP sows (P = 0.12). When the sows were categorized according to return to estrus (WOI ≤ 8 or > 8 d), basal and mean concentrations of LH increased after weaning only in sows with a short WOI. Sows with a delayed estrus exhibited a higher ratio of plasma tyrosine to large neutral amino acids (AA, P < 0.01). In conclusion, large body reserves at farrowing buffer, at least in part, the detrimental effect of a strongly negative nitrogen balance on reproduction. We suggest that the alteration of AA profiles induced by dietary protein restriction and body protein loss alters LH secretion via modifications of the neurotransmitters involved in GnRH secretion.sow / rearing / lactation / protein intake / amino acid / reproductive performance

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“…As judged on the basis of body weight gain, growth is faster in European White breeds than in Meishan pigs. 2) On the other hand, puberty is earlier in Meishan pigs than in European White breeds, [3][4][5] and Meishan pigs are more prolific than European White breeds. 6,7) Another distinctive feature is that Meishan pigs have a lot of adipose tissue, as compared with European White breeds.…”

Section: Introductionmentioning

confidence: 99%

Gender-Related Differences in the Level of Serum Lipids in Meishan Pigs

Kojima

Sekimoto²,

Degawa³

2008

JOURNAL OF HEALTH SCIENCE

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Levels of serum lipids such as total cholesterol (T-CHO), free cholesterol (F-CHO), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), and phospholipids (PL) were examined in both sexes of Meishan pigs. In young adult pigs (4-to 5-monthold), levels of all above lipids mentioned were significantly higher in females than in males, while no such sex difference was observed until the age of 3 months. In young adult male pigs castrated at the age of 1 month, levels of these lipids were almost the same as levels in corresponding female pigs. In addition, no sex differences in the levels of high density lipoprotein cholesterol and non-esterified free fatty acids were observed. The present findings indicated that androgen might act as a down-regulator for the levels of serum lipids, such as T-CHO, F-CHO, LDL-C, TG and PL, in pigs.

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Patterns of plasma LH, FSH, oestradiol and corticosteroids from birth to the first oestrous cycle in Meishan gilts

Abstract: Hormonal changes associated with pubertal development in a breed of pig exhibiting early puberty were determined. In Expt 1, blood from prepubertal Meishan

Cited by 31 publications

References 18 publications

Physiological mechanisms of ovarian follicular growth in pigs — A review

Physiological mechanisms of ovarian follicular growth in pigs — A review

Dietary protein restriction during lactation in primiparous sows with different live weights at farrowing: II. Consequences on reproductive performance and interactions with metabolic status

Gender-Related Differences in the Level of Serum Lipids in Meishan Pigs

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