The role of genetic regulators in boosting sow fertility
Chinese researchers recently discovered a genetic mutation and a long non-coding RNA linked to sow fertility, publishing their findings in Advanced Science.
Sow fertility is a key factor in swine farming, directly impacting production and profitability. While researchers have identified many genes that influence fertility, non-coding RNAs—molecules that do not directly make proteins but play crucial roles in gene regulation—are often overlooked. Scientists recently discovered one of these hidden players, called NORSF, which affects ovarian health and fertility in sows. Their study, published in Advanced Science, highlights how this long non-coding RNA contributes to cell death in ovarian follicles, impacting sow reproductive performance.
Data collection
The researchers randomly selected 679 sows for this trial. They collected ovary, heart, liver, spleen, lung, kidney, colon, small intestine, and muscle samples from a slaughterhouse. They isolated sow granulosa cells from follicles in ovaries, inoculated them into culture plates, and artificially introduced RNAs into them. Then, they determined the rate of granulosa cell death. In the next step, they conducted total RNA isolation and quantification and analysed tissue expression profiles. Finally, they performed a polymerase chain reaction to detect DNA fragments of NORSF transcripts, a nuclear long non-coding RNA that contributes to the follicular atresia and restrains oestradiol release by granulosa cells.
Potential candidate non-coding RNA for sow fertility traits
The researchers found 943 genetic regions (quantitative trait loci) linked to 28 fertility traits spread across 19 pig chromosomes. Most were located on chromosome 1, while chromosome X had the fewest. Among the traits, teat number had the most genetic links, followed by ovulation rate. In contrast, traits like anovulation, litter size, and uterine capacity had the fewest, indicating that traits with more genetic links are generally more significant.
One key RNA, strongly linked to ovarian function, was found to play a major role in follicular atresia
NORSF affects sow fertility traits
Every genetic region linked to sow fertility traits contained at least one possible non-coding RNA. One key RNA, strongly linked to ovarian function, was found to play a major role in follicular atresia. Mutations in this RNA alter protein-binding sites, affecting fertility. Its levels were higher in unhealthy follicles than in healthy ones, showing it contributes to cell death in ovarian follicles.
The authors concluded that NORSF was the first causal long non-coding RNA in the quantitative trait loci for sow fertility traits affecting granulosa cell death and follicular atresia.
