Exploring the Genetic Background of the Differences in Nest-Building Behavior in European Rabbit

Abstract

Once a day, nursing and absentee mothering make the wild rabbit (Oryctolagus cuniculus) an ideal model animal for measuring differences in maternal behavior. Behavioral events and their hormonal regulation leading to parturition are well documented; however, the genetic background behind individual differences in this complex process is unknown. Decreased progesterone hormone level and the reduction of progesterone receptor activity are crucial to initiating the collection of nest material. The progesterone receptor gene is a likely candidate affecting nest-building behavior. In addition to several known point mutations in the progesterone receptor gene of the European wild rabbit, we have found a new mutation in the promoter region of the gene at 2682 T > C. Although this new single nucleotide polymorphism (SNP) was not involved in the formation of the nest-building behavior, an SNP (2464G > A) already described in the promoter region showed an association with individual differences in the initiation of hay carrying. The distribution of this SNP delivered an opposite result compared to domestic rabbits. Genotype (GG) with high uterine capacity was most frequent; the hereditary value of the trait was h2 = 0.10. Thus, progesterone receptor gene polymorphism may manifest in individual differences affecting breeding success in this species.

Composition of the Wild Rabbit Nest and Its Implication for Domestic Rabbit Breeding

“…The even larger proportion of dry grass found in the final nests and occasional observations of the does in the nest chamber suggest a modification of the nest composition after the collection phase by eating some of the green grass (see Experiment 2 and 3), and thus the final composition of the nests was strikingly uniform and similar to the composition of the nests found in the field and made by the wild ancestors. It is important to emphasize that we tested naïve primiparous domestic does without any previous experience with the nest materials, and our observation focussed on the very first efforts in the nest construction, which is not affected by the does learning processes in handling or eating grasses Even though there has been some changes in the genetic background in the nest building behaviour due to domestication [63][64][65], the basic features of choosing the appropriate nest material seem to remain rather conservative. Thus, we recommend providing uncut hay as a nest material in the rabbit production as it seems to fulfil the basic needs of this domesticated animal.…”

Neurobiology of Maternal Behavior in Nonhuman Mammals: Acceptance, Recognition, Motivation, and Rejection

“…Some behaviors that start before parturition might be considered indirect maternal behaviors. For example, nest-building (e.g., digging, shredding paper, straw carrying, and hair pulling) and isolation from the pack or herd [ 10 , 11 , 12 , 13 ]. Other early behaviors, such as those observed in pregnant dogs, including restlessness, reduced appetite, lack of attention, drowsiness, aggression, anxiety, fickleness, capriciousness, irritation, and increase in attention request, may only reflect an imminent parturition [ 14 , 15 ].…”

Candidate genes associated with reproductive traits in rabbits

“…The product of this gene interacts with the progesterone hormone to play a vital role in fetus maintenance. It has also an indirect effect on reproduction by altering maternal behavior (Benedek et al, 2020 ). There are two isoforms of progesterone receptors (PR-A and PR-B).…”