Ovarian transcriptome profile from pre-laying period to broody period of Xupu goose

Xupu goose, a breed from Hunan province, produces high quality and quantity of meat and liver. However, its egg production rate is low, with poor reproductive traits but strong broody performance. These characteristics decrease the economic value of Xupu goose significantly. Here, RNA-seq was used to analyze the transcriptome changes of ovaries of Xupu goose at different stages to explore the molecular mechanism of reproduction from the pre-laying period to the broody period. A total of 258 genes were differentially expressed in the 3 stages. These genes are associated with inflammation, reproduction, mutual recognition and adhesion between cells, and cytoskeleton formation, and so on. In particular, we report, for the first time, the expression patterns of MRP126, serglycin, TXNIP, and FZD2 during the pre-laying, egg-laying, and broody periods of goose ovaries. Functional analysis by GO annotation revealed that GO terms were mainly involved in actin, cell signal transduction and regulation, and cellular components. Three pathways, including focal adhesion (gga04510), ECM-receptor interaction (gga04512), and N-Glycan biosynthesis (gga00510), were significantly enriched in the three groups. These findings provide a basis for further exploration of profiles of goose ovaries to improve egg production of Xupu goose.

Cloning and expression analysis of PRL and PRLR genes in black Muscovy duck

1. Prolactin hormone (governed by the PRL gene) is secreted by the anterior pituitary of animals, which combines with its receptor (prolactin receptor, PRLR) to act on target cells. Both PRL and PRLR are mainly associated with reproductive performance. The genetic mechanism of nesting in poultry is not yet clear, and so the aim of the current study was to determine expression patterns of PRL and PRLR at different times across the breeding stages of black Muscovy ducks.2. In this study, the CDS regions of PRL and PRLR were determined by RACE sequencing. The expression levels of PRL and PRLR in the pituitary, ovary and uterus from the black Muscovy duck were compared and analysed during the pre-laying, laying and nesting periods.3. The results showed that PRL and PRLR are highly homologous in a variety of poultry species. The expression of the PRL gene in the pituitary was the highest, which was significantly higher than seen in the ovary and uterus. This trend ran through the entire prenatal period, i.e. the laying period and the nesting period. The expression level of the PRLR gene in the pituitary and ovary was generally low, and expression in the uterus was the highest. There was no significant difference in expression of the PRLR gene between pituitary and ovary during different periods, but the expression level of the PRLR gene in the uterus reached its highest level during the nesting stage, which was significantly higher than seen in the early laying period.

Earlier colony arrival but no trend in hatching timing in two congeneric seabirds (Uria spp.) across the North Atlantic

A global analysis recently showed that seabird breeding phenology (as the timing of egg-laying and hatching) does not, on average, respond to temperature changes or advance with time (Keogan et al. 2018 Nat. Clim. Change 8, 313-318). This group, the most threatened of all birds, is therefore prone to spatio-temporal mismatches with their food resources. Yet, other aspects of the breeding phenology may also have a marked influence on breeding success, such as the arrival date of adults at the breeding site following winter migration. Here, we used a large tracking dataset of two congeneric seabirds breeding in 14 colonies across 18° latitudes, to show that arrival date at the colony was highly variable between colonies and species (ranging 80 days) and advanced 1.4 days/year while timing of egg-laying remained unchanged, resulting in an increasing pre-laying duration between 2009 and 2018. Thus, we demonstrate that potentially not all components of seabird breeding phenology are insensitive to changing environmental conditions.