The role of lipids in conception and early pregnancy in horses has been described as an unexplored frontier by researchers in Australia.
Lipids are microscopic non-soluble molecules that are important components of living cells. They are dynamic biological molecules that play key roles in metabolism, inflammation, cell signalling and structure.
They are also biologically significant in the physiology of conception and reproduction, Edwina Lawson and her fellow researchers wrote in their just-published review.
The review team, with the University of Newcastle and the University of Sydney, said many of the mechanisms surrounding equine conception and early pregnancy are yet to be understood at a biochemical level.
Recently, lipid-related technologies have advanced considerably and analytical strategies enhanced and diversified.
Consequently, in-depth lipid-related work now has the potential to reveal new lipid biomarkers and biochemical relationships to improve our understanding of the processes leading to efficient and successful reproduction.
In their review, published in the journal Reproduction and Fertility, the authors explored how lipids influence the reproductive cycle of mares, including ovulation and the detailed biological process of becoming pregnant.
They traversed how lipids are identified in a laboratory setting with a newly developing technology known as “lipodomics”.
They said it is well known that lipid metabolism represents a systematic interaction of genes, proteins, metabolites, lipids and enzymes.
“Apart from the roles of lipid-based steroid hormones in equine reproduction, not much is known about the roles of the other classes of lipids,” they concluded.
“It is established that localised lipid metabolism greatly changes during early fertilisation and pregnancy, but it is an under-investigated field of research in equine species.”
Understanding the roles of lipids during the preconception period and during early pregnancy may provide a valuable avenue to identify biomarkers of both fertility and early pregnancy, they said.
Further lipid profiling will likely provide valuable insights into the pathways and mechanisms surrounding fertilisation, they said.
“The effects of various follicular fluid lipids on oocytes, spermatozoa and oviductal epithelial cells will be pivotal in increasing our understanding of the biochemical cascade of events leading to fertilisation.”
This, they said, will potentially advance equine-assisted reproduction technology and improve pregnancy outcomes and foaling rates.
“These developments could bring the industry closer to making conventional in vitro fertilization (IVF) in horses possible, which would undoubtedly be a great scientific achievement.”
In-depth lipid-related processes are just starting to be explored, they said.
“There are always challenges that arise with the dawn of any emerging technology, which has been the case with lipidomics,” they said.
“In the field of lipidomics, there are large disparities in methodologies and technologies between studies, which have resulted in inconsistencies in published results.”
Despite standard protocols not yet being fully established, recent innovations in lipid research and revelations around some of the complex pathways involved in the synthesis of lipids has promising potential for future research.
“The study of lipids, the use of lipidomics and the upskilling of equine researchers with lipidomic technologies will undoubtedly progress the field of equine reproductive research, with the potential to solve the reproductive quandaries involved with equine fertilisation and embryo–maternal communication, and thus improve clinical practice.”
The authors observed that, remarkably, there are gaps in much of our knowledge about the finer details of pregnancy in the horse.
The review team comprised Lawson, Mark Baker, John Aitken, Aleona Swegen and Zamira Gibb, all with the University of Newcastle; and Christopher Grupen and Charley-Lea Pollard, with the University of Sydney.
Their work was funded by the Australian Research Council.
Conception and early pregnancy in the mare: lipidomics the unexplored frontier
Edwina F. Lawson, Christopher G. Grupen, Mark A. Baker, R. John Aitken, Aleona Swegen, Charley-Lea Pollard, and Zamira Gibb.
Reproduction and Fertility, March 10, 2022, https://doi.org/10.1530/RAF-21-0104