A large-effect locus on chromosome 4 underlies circadian feeding rhythmicity in pigs

Circadian feeding rhythmicity, or the regular pattern of food intake across the 24-hour day, is crucial for regulating metabolism and overall health in animals. However, various factors, both internal and external, can disrupt this natural rhythm. A recent study analyzed the hourly feeding behavior of over 18,000 pigs, with results published in the journal <source>source</source>.

The researchers found that genetic factors play a significant role in determining a pig's circadian feeding rhythm. Specifically, a large-effect locus on chromosome 4 was identified as the primary driver of this behavior. This genetic factor accounted for 5.3% of the phenotypic variance in Swiss Landrace pigs and 2.9% in Swiss Large White pigs.

The study also revealed that female and older pigs exhibited higher rhythmicity compared to males and younger animals. Additionally, pigs with stronger circadian feeding organization showed reduced nighttime feeding, improved feed conversion ratio, and lesser day-to-day variability in feed intake. These findings suggest that pigs with stable circadian feeding patterns are likely to have better feed efficiency and resilience.

The genome-wide analysis revealed that the identified locus overlaps with two genes, OPRK1 and NPBWR1, previously associated with feeding behavior, reward, and energy homeostasis. This discovery highlights the genetic basis of circadian feeding rhythms in pigs and opens up new avenues for further research into the genetic regulation of feeding behaviors in mammals.