Thyroid transcriptome analysis reveals different adaptive responses to cold environmental conditions between two chicken breeds

Abstract

Selection for cold tolerance in chickens is important for improving production performance and animal welfare. The identification of chicken breeds with higher cold tolerance and production performance will help to target candidates for the selection. The thyroid gland plays important roles in thermal adaptation, and its function is influenced by breed differences and transcriptional plasticity, both of which remain largely unknown in the chicken thyroid transcriptome. In this study, we subjected Bashang Long-tail (BS) and Rhode Island Red (RIR) chickens to either cold or warm environments for 21 weeks and investigated egg production performance, body weight changes, serum thyroid hormone concentrations, and thyroid gland transcriptome profiles. RIR chickens had higher egg production than BS chickens under warm conditions, but BS chickens produced more eggs than RIRs under cold conditions. Furthermore, BS chickens showed stable body weight gain under cold conditions while RIRs did not. These results suggested that BS breed is a preferable candidate for cold-tolerance selection and that the cold adaptability of RIRs should be improved in the future. BS chickens had higher serum thyroid hormone concentrations than RIRs under both environments. RNA-Seq generated 344.3 million paired-end reads from 16 sequencing libraries, and about 90% of the processed reads were concordantly mapped to the chicken reference genome. Differential expression analysis identified 46–1,211 genes in the respective comparisons. With regard to breed differences in the thyroid transcriptome, BS chickens showed higher cell replication and development, and immune response-related activity, while RIR chickens showed higher carbohydrate and protein metabolism activity. The cold environment reduced breed differences in the thyroid transcriptome compared with the warm environment. Transcriptional plasticity analysis revealed different adaptive responses in BS and RIR chickens to cope with the cold, and showed higher responsiveness in BS compared with RIR chickens, suggesting greater adaptability of the thyroid in BS chickens. Moreover, 10,053 differential splicing events were revealed among the groups, with RNA splicing and processing, gene expression, transport, and metabolism being the main affected biological processes, identifying a valuable alternative splicing repertoire for the chicken thyroid. A short isoform of TPO (encoding thyroid peroxidase) containing multiple open reading frames was generated in both breeds by skipping exons 4 and 5 in the cold environment. These findings provide novel clues for future studies of the molecular mechanisms underlying cold adaptation and/or acclimation in chickens.

Genetic and phenotypic responses to genomic selection for timing of breeding in a wild songbird

“…One of the most significant genes, the adipokine angiopoietin 1 ( ANGPT1, Table S3), is an important gene in angiogenesis (Koh, ) and has been shown to be part of follicular development in rats (Rudolph et al, ), pregnancy complications in humans (Andraweera et al, ) and may have a possible role in avian reproduction (Bornelöv et al, ). Another highly significant gene, glycerol‐3‐phosphate dehydrogenase 1‐like ( GPD1L, Table S3), has been shown to be linked to adaptive responses to temperature in chicken thyroids (Xie et al, ). Also, zona pellucida glycoprotein 4 ( ZP4 ) differentiated significantly between the selection lines.…”

Are Dual-Purpose Chickens Twice as Good? Measuring Performance and Animal Welfare throughout the Fattening Period

“…Present challenges in poultry production also include the increasing public interest in overall animal welfare, including physiology and animal behavior. Chickens of native breeds are believed to show a better adaptation to local housing conditions, which is a desirable breeding goal in poultry [14] and has also been reported for cattle in terms of climate adaptation [15,16]. This adaptation to the production environment is, with physical health, the key factor for welfare of farm animals, including poultry [17].…”

Endocrinology of thermoregulation in birds in a changing climate

“…However, there is some evidence on heritability of the mean levels of T3 in eggs (Ruuskanen et al, 2016b), suggesting scope for microevolutionary responses of THs to climate change. Interestingly, endocrine responses to thermal stress have been shown to vary among poultry breeds, potentially suggestive of genetic variation in temperature tolerance (Xie et al, 2018). Moreover, there is rather good evidence that individuals consistently differ in their CORT responses to standard stressor (Cockrem, 2013) as well as food stress (Lendvai et al, 2014), while CORT shows also moderate heritability (Stedman et al, 2017;Taff et al, 2018).…”