0.857
IF5
0.900
IF
Q3
JCR
0.92
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SJR
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SJR
20
MNiSW
165.24
ICV
ORIGINAL PAPER
 
CC-BY 4.0
 
 

Seasonal changes of melatonin secretion in relation to the reproductive cycle in sheep

T. Misztal 1,  
K. Romanowicz 1,  
 
1
The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jabłonna, Poland
J. Anim. Feed Sci. 1996;5(1):35–48
Publish date: 1996-01-12
KEYWORDS
ABSTRACT
The seasonal changes in circulating melatonin were determined in ewes and rams exposed to the natural photoperiod at 52°N during first year and in rams under the artificial daylength conditions (16D:8L), during the second year of the experiment. The changes in the luteotropin (LH) and testosterone (T) concentrations in blood plasma of rams were also monitored. The mean daily concentrations of plasma melatonin in the ewes varied through a year from 41 ± 7 to 112 ± 13 pg/ml and a significant increase above the daily values occured during the first hour after sunset. The duration of nightly melatonin secretion was longer during the period of short day (10-12h), than under the long day conditions (8-10h). The mean nightly concentrations of circulating melatonin were highest from August to February: 171 ± 73 to 329 ± 187 pg/ml for individual ewes. The mean concentrations of LH and testosterone in blood plasma of rams, under the natural photoperiod, were low during the period of sexual quiescence and the significantly high levels occured in August: 6.2 ± 0.4 ng/ml and in October: 4.6 ± 0.7 ng/ml, respectively. Shortening of daylength from 16 to 8 h in May evoked in rams an increase in duration of melatonin secretion from 6 to 14 h. This advanced reproductive function by 6 to 9 weeks, with the peak of LH and testosterone secretion noted at the beginning of July: 8.2 ± 0.9 ng/ml and in August: 5.2 ± 0.9 ng/ml, respectively. Nevertheless the duration of reproductive activity of rams during the second year of the experiment was shorter than under the natural photoperiodic conditions.
 
CITATIONS (12):
1. In vitro evidence that leptin suppresses melatonin secretion during long days and stimulates its secretion during short days in seasonal breeding ewes
Dorota A. Zieba, Beata Klocek, Gary L. Williams, Katarzyna Romanowicz, Lukasz Boliglowa, Malgorzata Wozniak
Domestic Animal Endocrinology
2. Short-day and melatonin effects on milking parameters, prolactin profiles and growth-hormone secretion in lactating sheep
Edyta Molik, Tomasz Misztal, Katarzyna Romanowicz, Dorota Zieba
Small Ruminant Research
3. Effects of orexigenic peptides and leptin on melatonin secretion during different photoperiods in seasonal breeding ewes: An in vitro study
D.A. Zieba, K. Kirsz, E. Molik, K. Romanowicz, A.K. Wojtowicz
Domestic Animal Endocrinology
4. Dependence of the lactation duration and efficiency on the season of lambing in relation to the prolactin and melatonin secretion in ewes
Edyta Molik, Tomasz Misztal, Katarzyna Romanowicz, Edward Wierzchoś
Livestock Science
5. Plasma and cerebrospinal fluid interleukin-1β during lipopolysaccharide-induced systemic inflammation in ewes implanted or not with slow-release melatonin
Janina Skipor, Marta Kowalewska, Aleksandra Szczepkowska, Anna Majewska, Tomasz Misztal, Marek Jalynski, Andrzej P. Herman, Katarzyna Zabek
Journal of Animal Science and Biotechnology
6. Melatonin from slow-release implants did not influence the gene expression of the lipopolysaccharide receptor complex in the choroid plexus of seasonally anoestrous adult ewes subjected or not to a systemic inflammatory stimulus
M. Kowalewska, A. Szczepkowska, A.P. Herman, M.T. Pellicer-Rubio, M. Jałyński, J. Skipor
Small Ruminant Research
7. The effects of melatonin on prolactin and growth hormone secretion in ewes under different photoperiods, during the early post partum period
E. Molik, T. Misztal, K. Romanowicz, D.A. Zieba
Small Ruminant Research
8. Effect of melatonin on daily LH secretion in intact and ovariectomized ewes during the breeding season
Tomasz Misztal, Katarzyna Romanowicz, Bernard Barcikowski
Animal Reproduction Science
9. Effects of ghrelin on nocturnal melatonin secretion in sheep: An in vitro and in vivo approach1
K. Kirsz, M. Szczesna, E. Molik, D. A. Zieba
Journal of Animal Science
10. Seasonal changes in the interactions among leptin, ghrelin, and orexin in sheep1
K. Kirsz, M. Szczesna, E. Molik, T. Misztal, A. K. Wojtowicz, D. A. Zieba
Journal of Animal Science
11. The effects of leptin on plasma concentrations of prolactin, growth hormone, and melatonin vary depending on the stage of pregnancy in sheep1
Malgorzata Szczesna, Katarzyna Kirsz, Tomasz Misztal, Edyta Molik, Dorota A Zieba
Journal of Animal Science
12. Milk yield, lactation parameters and prolactin secretion characteristics in sheep treated with melatonin implants during pregnancy and lactation in long-day conditions
Tomasz Misztal, Edyta Molik, Michał Nowakowski, Elżbieta Marciniak
Livestock Science
ISSN:1230-1388