The effect of calving in the summer on the hepatic transcriptome of Holstein cows during the peripartal period
Author(s)
Date Issued
2015
Type
article
Volume
98
Issue
98
Start Page
5401
End Page
5413
ISSN
15253198
220302
Journal
Abstract
The liver is the main metabolic organ coordinating
the adaptations that take place during the peripartal
period of dairy cows. A successful transition into lactation, rather than management practices alone, depends
on environmental factors such as temperature, season
of parturition, and photoperiod. Therefore, we analyzed
the effect of calving season on the hepatic transcriptome of dairy cows during the transition period. A total
of 12 Holstein dairy cows were assigned into 2 groups
based on calving season (6 cows March–April, spring; 6
cows June–July, summer, SU). The RNA was extracted
from liver samples obtained at −30, 3, and 35 DIM
via percutaneous biopsy and hybridized to the Agilent
44K Bovine (V2) Gene Expression Microarray (Agilent
Technologies Inc., Santa Clara, CA). A quantitative
PCR on 22 target genes was performed to verify and
expand the analyses. A total of 4,307 differentially
expressed genes were detected (false discovery rate
≤0.05) in SU compared with spring. Furthermore, 73
unique differentially expressed genes were detected in
SU compared with spring cows after applying a foldchange threshold ≥3 and ≤−3. For Kyoto Encyclopedia
of Genes and Genomes pathways analysis of differentially expressed genes, we used the dynamic impact
approach. Ingenuity Pathway Analysis software was
used to analyze upstream transcription regulators and
perform gene network analysis. Among metabolic pathways, energy metabolism from lipids, carbohydrates,
and amino acids was strongly affected by calving in SU,
with a reduced level of fatty acid synthesis, oxidation,
re-esterification, and synthesis of lipoproteins, leading
to hepatic lipidosis. Glycan-synthesis was downregulated in SU cows probably as a mechanism to counteract the progression of this lipidosis. In contrast, calving in
the SU resulted in upregulation of gluconeogenesis but
also greater use of glucose as an energy source. Among
nonmetabolic pathways, the heat-shock response was
obviously activated in SU cows but was also associated
with inflammatory and intracellular stress response.
Furthermore, data support a recent finding that cows
experience endoplasmic reticulum stress around parturition. Transcription regulator analysis revealed how
metabolic changes are related to important regulatory
mechanisms, including epigenetic modification. The
holistic analyses of the liver transcriptome response to
calving in the summer at high environmental temperatures underscore how transition cows should be carefully managed during this period, as they experience
alterations in liver energy metabolism and inflammatory state increasing susceptibility to health disorders
in early postpartum.
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JDS - For peer review.pdf
Description
Accepted version
Size
1.48 MB
Format
Adobe PDF
Checksum (MD5)
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Conference(s)
JOURNAL OF DAIRY SCIENCE