Biology subjects

Gorssen, W.

Publications and source records attributed to Gorssen, W..

4 recordsLinked to original sources

bioRxiv2026

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

Circadian feeding rhythmicity reflects the distribution of feed intake across the daily 24-hour cycle. Regular feeding-fasting cycles play an important role in regulating metabolism and maintaining health, but endogenous and environmental factors can disrupt the normal circadian pattern of feed intake. Here, we quantified hourly feed intake in 3,470 Swiss Landrace and 15,181 Swiss Large White pigs using 40.5 million records from automated feeding systems. We used the proportion of days exhibiting a significant feeding rhythm after wavelet analysis to investigate variation in circadian feeding organization. Circadian feeding rhythmicity was influenced by sex and age, with higher rhythmicity observed in females and older animals. Variance components analysis revealed a strong additive genetic contribution and a high heritability (0.53-0.57). Pigs with higher circadian feeding rhythmicity had reduced nocturnal intake, improved feed conversion ratio, and lower day-to-day variability in feed intake, suggesting improved feed efficiency and resilience. Genome-wide association testing of 15.7 and 23.1 million imputed sequence variants identified a QTL on chromosome 4 explaining 5.3% and 2.9% of the phenotypic variance of circadian feeding rhythmicity in Swiss Landrace and Swiss Large White pigs, respectively. The QTL overlaps OPRK1 and NPBWR1, two genes implicated in the regulation of feeding behavior, reward and energy homeostasis. Collectively, our findings establish circadian feeding behavior as a heritable trait in pigs and provide a basis to further investigate the genetic regulation of feeding rhythms in mammals and explore its use in animal breeding programs to improve feed efficiency and resilience.

genetics↗

bioRxiv2026

Pig vocalizations contain shared acoustic structure for humans and machines, but limited evidence for presumed affective valence

Vocalizations are increasingly proposed as indicators of affective state in animal welfare research. Yet many studies assign context-derived affective valence to vocalizations and then classify these using machine learning according to those context-derived labels. This circular dependence makes it unclear whether successful classification reflects affective state itself, broader contextual or acoustic differences, or the interpretive categories imposed by the task. Therefore, we examined human organization of pig vocalizations using free-classification and forced-choice tasks, and compared these patterns with acoustic structure recovered by convolutional neural network models. In a free-classification task, 224 participants sorted 2,192 pig vocalizations into self-defined categories. Next, in two forced-choice tasks, 159 participants recruited in a second wave classified vocalizations using predefined context and valence categories. Free classification revealed reproducible but broad perceptual structure rather than recovery of discrete recording contexts. Participant-generated labels for pig vocalizations were predominantly descriptive and spontaneous valence-related labeling was limited (19.6%) yet primarily negative. Forced-choice classification of recording context was weak (8.0% exact accuracy) and showed only slight agreement with source contexts. Valence judgments were more structured (60.1% exact accuracy), but agreement with the valence categories used to characterize the recording contexts was modest and largely driven by highly aversive situations such as castration, restraint, fighting, and crushing. After excluding pig vocalizations from these contexts, agreement with context-associated valence categories disappeared. Human-derived perceptual structure closely corresponded to convolutional neural network embedding spaces, indicating that human listeners and machine-learning models recovered similar acoustic organization. These findings suggest that pig vocalizations contain robust and recoverable acoustic organization, but that this organization only partially aligns with the contextual and valence frameworks commonly used to interpret it. More broadly, the results highlight a distinction between recovering acoustic structure and establishing its biological meaning, with implications for affective research and animal welfare assessment. Significance StatementAnimal vocalizations are increasingly used to infer affective state and welfare, yet affective labels are often assigned from the recording context rather than independently validated. We show that humans and machine-learning models recover similar acoustic organization in pig vocalizations, especially for highly aversive situations, but that this organization only partially corresponds to the context-derived valence categories used to interpret the vocalizations. These findings show that successful classification of vocalizations based on context-derived presumed valence does not necessarily establish their affective or welfare meaning. Vocal indicators of welfare therefore require validation against behavioral, physiological, and other independent measures rather than reliance on contextual classifications alone.

animal behavior and cognition↗

bioRxiv2025

Genetic analysis of iris pigmentation in Swiss pig breeds identifies a missense KITLG variant as a potential causal factor for pale and heterochromatic irises

BackgroundIris pigmentation is a heritable trait with a complex genetic architecture. While the genetic basis of iris pigmentation has been extensively studied in humans, little is known about iris pigmentation in pigs. Iris pigmentation in pigs varies from different shades of brown or pale irises to heterochromia manifesting either as different colors between both irises (heterochromia iridum) or multiple colors within a single iris (heterochromia iridis). This study investigates the genetics of iris pigmentation variability in the Swiss Landrace and Swiss Large White pig breeds. ResultsIris pigmentation was phenotyped in 837 Swiss Landrace and 328 Swiss Large White pigs of which the majority also had array-derived genotypes. A high prevalence of heterochromia iridum (18.6%) was observed in the Swiss Landrace breed. Heritability estimates for iris pigmentation were high in both breeds (h{superscript 2} = 56.0-57.2%). Iris pigmentation was not genetically correlated with production traits. Genome-wide association analysis identified several loci associated with iris pigmentation, including regions near functional candidate genes such as TYR, ALX4 and DCT. The strongest association was detected near the KITLG gene, which was identified as a candidate gene for iris pigmentation in a previous study on Italian Large White pigs. Fine-mapping identified a highly significantly associated (P=3.8x10-11) missense variant in KITLG (5_94084790_G>A, rs342599807, p.R124K) as a potential causal variant for pale and heterochromatic iris pigmentation in Swiss pigs. ConclusionsOur findings provide new insights into the genetic architecture of iris pigmentation in pigs and indicate that KITLG plays a key role. The identification of a putative causal missense variant offers a foundation for further functional studies aiming to better understand pigmentation traits in pigs.

genomics↗

bioRxiv2021

High heritabilities for antibiotic usage show potential to breed for disease resistance in finishing pigs

The use of antimicrobials in animal production is under public debate, mainly due to the risk of transfer of resistance to pathogenic bacteria in humans. Therefore, measures have been taken during the last decades to reduce antibiotic usage in animals, for instance by national monitoring programmes and by improving animal health management. Although some initiatives exist in molecular genetic selection, quantitative genetic selection of animals towards decreased antibiotic usage is an underexplored area to reduce antibiotic usage. However, this strategy could yield cumulative effects. In this study we derived new phenotypes from on-farm parenteral antibiotic records from commercially grown crossbred finishing pigs used in the progeny test of Pietrain terminal sires to investigate the heritability of antibiotics usage. Parenteral antibiotic records, production parameters and pedigree records of 2238 fullsib pens from two experimental farms in Belgium between 2014 and 2020 were analysed. Heritability estimates were moderate (18-44%) for phenotypes derived from all antibiotic treatments, and low (1-15%) for phenotypes derived from treatments against respiratory diseases only. Moreover, genetic correlations between these new phenotypes and mortality were low to moderate (0.08-0.60) and no strong adverse genetic correlations with production traits were found. The high heritabilities and favourable genetic correlations suggest these new phenotypes derived from on-farm antibiotics records to be promising for inclusion in future pig breeding programs to breed for a decrease in antibiotics usage.

genetics↗