Physiological state and photoperiod exposures differentially influence circadian rhythms of body temperature and prolactin and relate to changes in mammary PER1 expression in late pregnant and early lactation dairy goats

Mugagga Kalyesubula, Theresa M. Casey, Naama Reicher, Chris Sabastian, Yossi Wein, Enav Bar Shira, Nguyen Hoang, Uduak Z. George, Avi Shamay, Karen Plaut, Sameer J. Mabjeesh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Short-day photoperiod (SDPP; 8 h light:16 h dark) during the dry period increases milk production compared with long-day photoperiod (LDPP; 16 h light:8 h dark). We hypothesized that the impact of photoperiod on lactation is mediated by alterations in the circadian system. Twelve Saanen goats were blocked at dry off into SDPP (n = 6) and LDPP (n = 6) treatments and mammary biopsies were taken in the middle of light and dark phases at 3 wk prepartum and 5 wk postpartum. Total RNA was isolated, and the expression of clock genes was analyzed by qPCR. SDPP goats produced more milk than LDPP goats (3.15 ± 0.04 vs. 2.7 ± 0.05 kg/d). In the 24 h period, LDPP goats had a greater body temperature than SDPP goats at 3 wk prepartum (39.6 ± 0.06 vs. 39.3 ± 0.1 °C) and 5 wk postpartum (40.1 ± 0.15 vs. 39.7 ± 0.1 °C). Cosinor analysis revealed that physiological state affected body temperature mesor (P< 0.001), peak (P< 0.01), amplitude (P< 0.05), and phase (P< 0.001). Plasma prolactin was 20, 10, and 17-fold higher in LDPP than in SDPP goats at 3 wk prepartum, 3 wk postpartum and 5 wk postpartum, respectively. Cosinor analysis revealed that photoperiod affected prolactin mesor (P< 0.0001), peak (P< 0.0001), trough (P< 0.001), amplitude (P< 0.01), and the peak to trough ratio (P< 0.01). Mammary expression of a core clock gene, PER1, was affected by the light-dark phase and the photoperiod treatment (P< 0.05). It also exhibited a photoperiod-physiological state interaction. Changes in the circadian rhythms with the onset of lactation and photoperiod manipulation support further studies of their role in the regulation of milk yield.

Original languageAmerican English
Article number106394
JournalSmall Ruminant Research
Volume200
DOIs
StatePublished - Jul 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Circadian rhythms
  • Goat
  • Lactation
  • Mammary gland
  • Photoperiod

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