Profile of gonadotropic hormone secretion in sheep with disturbed rhythm of seasonality E., Błasiak M., Misztal T., Romanowicz K., Zięba D.A. (2017): Profile of gonadotropic hormone secretion in sheep with disturbed rhythm of seasonality. Czech J. Anim. Sci., 62: 242-248.
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The effect of artificial conditions of a short daylight period (16 h darkness (D): 8 h light (L)) and exogenous melatonin on milk yield parameters of sheep during spring and summer was examined to determine the impact of using sheep for milk on the secretion level of gonadotrophic hormones. The research was conducted on 60 sheep lambed in February. After raising the lambs, the sheep were divided into 3 groups and assigned for dairy use (May–September). The mothers in the control Group 1 (G1) were maintained under natural daylight conditions. The sheep in Group 2 (G2) were maintained under conditions of an artificial photoperiod (16 h D : 8 h L). Meanwhile, the mothers in Group 3 (G3) were given melatonin implants. A 6-hour collection of blood from 6 sheep of each group was performed every 4 weeks. The concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in plasma were measured using radioimmunoassay. The average LH concentration in G1 gradually increased since May (5.32 ± 0.2 ng/ml), reaching the highest value in August (6.70 ± 0.2 ng/ml). In G2, the increase in LH occurred 4 weeks after the introduction of the 16 h D : 8 h L condition (6.26 ± 0.2 ng/ml). The maximum LH concentration in G3 was noted in August (7.31 ± 0.2 ng/ml). The average FSH concentration in G1 gradually increased since May (6.59 ± 0.2 ng/ml), reaching the highest value in August (10.50 ± 2.6 ng/ml). In G2, there was a significant increase in the FSH concentration in June (9.00 ± 0.3 ng/ml). In the final period during lactation, the FSH concentrations in G2 (13.51 ± 1.3 ng/ml) and G3 (13.60 ± 1.9 ng/ml) were higher than in G1. The results indicate that using sheep for milk does not inhibit the secretion of gonadotropic hormones induced by the simulation of short daylight conditions and exogenous melatonin.
Amstalden M. (2003): Leptin Acts at the Bovine Adenohypophysis to Enhance Basal and Gonadotropin-Releasing Hormone-Mediated Release of Luteinizing Hormone: Differential Effects Are Dependent upon Nutritional History. Biology of Reproduction, 69, 1539-1544
Christian H. C., Imirtziadis L., Tortonese D. (2015): Ultrastructural Changes in Lactotrophs and Folliculo-Stellate Cells in the Ovine Pituitary during the Annual Reproductive Cycle. Journal of Neuroendocrinology, 27, 277-284
Ciechanowska M.O., Łapot M., Mateusiak K., Paruszewska E., Malewski T., Przekop F. (2017): Biosynthesis of gonadotropin-releasing hormone (GnRH) and GnRH receptor (GnRHR) in hypothalamic–pituitary unit of anoestrous and cyclic ewes. Canadian Journal of Physiology and Pharmacology, 95, 178-184
Clarke I.J., Arbabi L. (2016): New concepts of the central control of reproduction, integrating influence of stress, metabolic state, and season. Domestic Animal Endocrinology, 56, S165-S179
Goodman R. L., Jansen H.T., Billings H. J., Coolen L.M., Lehman M. N. (2010): Neural Systems Mediating Seasonal Breeding in the Ewe. Journal of Neuroendocrinology, , no-no
Kovacs M., Seprodi J., Koppan M., Horvath J. E., Vincze B., Teplan I., Flerko B. (2002): Lamprey Gonadotropin Hormone-Releasing Hormone-III has No Selective Follicle-Stimulating Hormone-Releasing Effect In Rats. Journal of Neuroendocrinology, 14, 647-655
Knobil E. (1980): The neuroendocrine control of the menstrual cycle. Recent Progress in Hormone Research, 36, 53–88.
Lincoln G.A. (1992): Administration of melatonin into the mediobasal hypothalamus as a continuous or intermittent signal affects the secretion of follicle stimulating hormone and prolactin in the ram. Journal of Pineal Research, 12, 135-144
Malpaux B. (1993): Short-day effects of melatonin on luteinizing hormone secretion in the ewe: evidence for central sites of action in the mediobasal hypothalamus. Biology of Reproduction, 48, 752-760
Marubayashi U., Yu W. H., McCann S. M. (1999): Median Eminence Lesions Reveal Separate Hypothalamic Control of Pulsatile Follicle-Stimulating Hormone and Luteinizing Hormone Release. Experimental Biology and Medicine, 220, 139-146
Misztal Tomasz, Romanowicz Katarzyna, Barcikowski Bernard (2002): Effect of melatonin on daily LH secretion in intact and ovariectomized ewes during the breeding season. Animal Reproduction Science, 69, 187-198
Misztal Tomasz, Romanowicz Katarzyna, Barcikowski Bernard (2004): Effects of melatonin on luteinizing hormone secretion in anestrous ewes following dopamine and opiate receptor blockade. Animal Reproduction Science, 81, 245-259
Molik Edyta, Misztal Tomasz, Romanowicz Katarzyna, Wierzchoś Edward (2007): Dependence of the lactation duration and efficiency on the season of lambing in relation to the prolactin and melatonin secretion in ewes. Livestock Science, 107, 220-226
Molik E., Misztal T., Romanowicz K., Zieba D., Wierzchos E. (2009): Changes in growth hormone and prolactin secretion in ewes used for milk under different photoperiodic conditions. Bulletin of the Veterinary Institute in Pulawy, 53, 389–393.
Molik E., Pasternak M., Blasiak M., Misztal T., Romano-wicz K., Zieba D. (2013): The effect of the diversified signal of melatonin on milk yields in seasonally breeding sheep. Archiv Tierzucht, 56, 924–932.
Norms (1993): Nutrient Requirements for Cattle and Sheep in the Traditional System. IZ Krakow, Poland. (in Polish)
Padmanabhan Vasantha, Evans Neil P., Dahl Geoffrey E., McFadden Kristin L., Mauger David T., Karsch Fred J. (1995): Evidence for Short or Ultrashort Loop Negative Feedback of Gonadotropin-Releasing Hormone Secretion. Neuroendocrinology, 62, 248-258
Russel A. J. F., Doney J. M., Gunn R. G. (1969): Subjective assessment of body fat in live sheep. The Journal of Agricultural Science, 72, 451-
Stupnicki R., Madej A. (1976): Radioimmunoassay of LH in blood plasma of farm animals. Endokrinologie, 68, 6–13.
Thiéry J.C, Chemineau P, Hernandez X, Migaud M, Malpaux B (2002): Neuroendocrine interactions and seasonality. Domestic Animal Endocrinology, 23, 87-100
Tortonese D.J. (2016): Intrapituitary mechanisms underlying the control of fertility: key players in seasonal breeding. Domestic Animal Endocrinology, 56, S191-S203
Tricoire Hélène, Locatelli Alain, Chemineau Philippe, Malpaux Benoît (2002): Melatonin Enters the Cerebrospinal Fluid through the Pineal Recess. Endocrinology, 143, 84-90
Woodfill C. J. (1994): Photoperiodic synchronization of a circannual reproductive rhythm in sheep: identification of season-specific time cues. Biology of Reproduction, 50, 965-976
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