The neuropeptide oxytocin is an important regulator of mammalian social behaviour; playing a crucial role in the onset and maintenance of maternal behaviour. Studies in the chicken and turkey have demonstrated that the avian orthologue of oxytocin, mesotocin, is necessary for the rearing of chicks once they hatch. Mesotocin, and the related nonapeptide vasotocin, are synthesized in specific regions of the avian brain including those areas of the neural social network such as the paraventricular nucleus of the hypothalamus (PVN) and the bed nucleus of the stria terminalis (BnST). In this study we used in situ hybridisation (ISH) to quantify changes in mesotocin mRNA in the PVN and BnST from egg laying to chick rearing in the domestic chicken (silkie x leghorn cross). Brains were collected from laying hens, hens that had been incubating for 3 days or 2 weeks and hens which had hatched chicks and had been displaying maternal care for 24 hours (n=5-8 per group). All brains were immediately frozen on dry ice and sectioned on a cryostat at 15µm. Every fourth section was used for quantitative radioactive ISH. Hens rearing chicks showed higher mesotocin mRNA expression in the medial PVN compared to laying hens (P<0.05). There was no difference between other groups. During incubation mesotocin mRNA expression decreased in the lateral BnST compared to laying and chick rearing (P<0.05). Our research confirms a role for mesotocin in avian maternal behaviour, but further studies are required to investigate why levels of mesotocin decrease during incubation. Reasons for the observed changes in mesotocin mRNA expression from egg laying to chick rearing include stress response modulation and/or the reduction in social behaviour during incubation.
|Conference||Eleventh International Symposium on Avian Endocrinology|
|Period||11/10/16 → 14/10/16|